Cancelling Out CPU Fan Noise

I should have patented it... by zeux · 2004-03-15 13:34 · Score: 3, Interesting

I though about it a long time ago because I know we are using the same kind of technology in the airports.

Near the landing strips you can sometimes find some "sound reflectors" which just reflect the sound wave they receive from the planes. The sound is then cancelled by itself.

I saw it once in an airport in France and it works really well and costs next to nothing. AFAIK there's no sound wave modification in that system but I'm not sure (maybe the surface of the reflectors is made in a certain shape to change the sound wave a little).

But in this case it's different because the "box" must produce the counter sound wave. It's not just reflection, there is sound generation here. It means that the microphone and the speakers must be very precise or you just end up with more sound.

But if this guy can do it with 20 bucks it means that it's much easier than I though.

--
Iraq: war to save the U

Re:I should have patented it... by Anonymous Coward · 2004-03-15 13:37 · Score: 5, Informative

What you describe is not that same thing which is mentioned in that article. You describe passive cancellation (i.e. simply reflecting and hoping it will cancel the original noise), whereas the article describes active cancellation (i.e. recording the noise, computing the negating and sending it off) of noise.
Re:I should have patented it... by Anonymous Coward · 2004-03-15 13:39 · Score: 1, Funny

But if this guy can do it with 20 bucks it means that it's much easier than I though.
Either that or he's much smarter than you. Which I would imagine is the case if he's a professor at Boston...
Re:I should have patented it... by falconed · 2004-03-15 13:40 · Score: 2

I've always hated the noise, but never wanted to do water cooling because of the cost (and the water). The article says this will "add only about $20 to the cost of a personal computer." IMHO that would be $20 well spent to cancel out my noisyass thermaltake fan.

--
USE='clever' emerge -u sig
Re:I should have patented it... by Anonymous Coward · 2004-03-15 13:41 · Score: 2, Informative

Read my post carefully, I actually talk about both technology.
Re:I should have patented it... by Martin+Blank · 2004-03-15 13:43 · Score: 4, Interesting

I have a question about active cancellation, as I've heard of it being used in other places. Does the cancellation of a noise of a given frequency have any potentially harmful effects that become less obvious through cancellation? For example, does a high-pitch tone that could cause hearing loss over time become more dangerous now that there are two high-pitch tones (albeit directly off-phase) now sounding, or is the cancellation that complete?

--
You can never go home again... but I guess you can shop there.
Re:I should have patented it... by zeux · 2004-03-15 13:43 · Score: 5, Funny

Of course he is much smarter than I am, otherwise I wouldn't be posting on slashdot.

And I'm French, remember ;)

--
Iraq: war to save the U
Re:I should have patented it... by fireweaver · 2004-03-15 13:53 · Score: 5, Informative

Not to worry, the cancellation -can be- that complete. In practice, there will be some residual noise, but it will be very quiet.
Re:I should have patented it... by Reverberant · 2004-03-15 13:54 · Score: 4, Informative

Near the landing strips you can sometimes find some "sound reflectors" which just reflect the sound wave they receive from the planes. The sound is then canceled by itself.
I think you're referring to a "blast fence." Those have nothing to do with active sound cancellation, they're strictly passive noise control devices that block the path between the noise source and the receiver (just like highway noise barriers). See here or here for examples (the latter is a run-up enclosure, but it's the same principle).
Re:I should have patented it... by bcrowell · 2004-03-15 13:59 · Score: 5, Informative

If you can't hear it, it's not hurting you (assuming that it's a frequency that you could normally hear). Typically what will happen with a scheme like this is that the cancellation will only work in one direction. In other directions, it will reinforce rather than cancelling. For instance, you can buy noise-cancelling headphones, but the cancellation only works for your own ears, which gets the sound in just right right phase; to the people around you, there will be a perceptible noise coming from your headphones! Conservation of energy says you can't just destroy the energy of those sound waves. Most likely you're just sending extra-strength sounds waves somewhere else. Theoretically the extra energy could be converted into heat, or electrical energy, but I doubt that's really practical.

--
Find free books.
Re:I should have patented it... by Anonymous Coward · 2004-03-15 14:13 · Score: 1, Insightful

A noise canceller that makes the original noise worse? Errr....that's just a broken noise canceller, not a potentially damaging side effect. Even the most rudimentary testing of it would reveal any accidental reinforcement, and it probably wouldn't wind up being a very popular product.
Re:I should have patented it... by Cosmic_Hippo · 2004-03-15 14:27 · Score: 5, Interesting

For instance, you can buy noise-cancelling headphones, but the cancellation only works for your own ears, which gets the sound in just right right phase; to the people around you, there will be a perceptible noise coming from your headphones! Conservation of energy says you can't just destroy the energy of those sound waves. Most likely you're just sending extra-strength sounds waves somewhere else.

I own a set of noise cancelling headphones and there is no perceptible noise being emmitted from them to the outside world. The noise cancellation circuitry takes the incoming signal and inverts it to cancel out the original incoming sound wave. Conservation of energy doesn't really apply. You aren't really destroying the energy of the sound waves, just cancelling it. Energy is spent on both the positive and negative signal. Although I just minored in acoustics so I'm probably missing something. Any professional opinion is appreciated.
Re:I should have patented it... by bcrowell · 2004-03-15 14:37 · Score: 5, Interesting

Any professional opinion is appreciated.
Well, I do have a PhD in physics, but I should bow to your actual experience with the device :-)
My guess is that the sound coming into your ears is only a tiny amount of power, so reradiating that power in all directions doesn't make any amount of sound that would be perceptible to someone a significant distance away. Your eardrums only have a surface area of a few square mm, the the amount of energy impinging on them is normally only a gazillionth of a watt. Your ears are amazingly sensitive devices.
Conservation of energy doesn't really apply.
I was obviously wrong in my prediction about an audible noise for people not wearing the headphones, but I'll bet both my testicles that it's not because conservation of energy is violated. You'd get the Nobel Prize if you found a violation of conservation of energy.

--
Find free books.
Re:I should have patented it... by layingMantis · 2004-03-15 14:46 · Score: 1

I used to do this with my infinity RS-325 speakers (well just one of 'em actually) to cancel out my roommates annoying fscking snores. They were on the floor next to my bed and I just pointed them at his bed, heh. Course you had to be able to put up with very low music playing while trying to sleep, but...low bassy stuff worked bestIIRC.

~mantis
Re:I should have patented it... by ColMustard · 2004-03-15 14:54 · Score: 2, Informative

he's a professor at Boston...

Boston? BYU is Brigham Young University, a private school located in Provo, Utah. It is a somewhat prestigious university in its own right, but it certainly isn't any school in Boston.

--
Moof.
Re:I should have patented it... by Cosmic_Hippo · 2004-03-15 15:05 · Score: 4, Interesting

Heh, I hope I wasn't implying that conservation of energy was being violated. I just though that destruction of energy and cancellation of the signal were different in this case. I think I worded it wrong. No testicles need to be wagered :-)
The experience I've had with the equipment in class showed that the noise cancellation circuitry recorded the original sound wave, inverted it and fed it back into the speaker. The combination of positive and negative voltage basically told the speaker to output zero signal for that particular frequency. Nothing is destroyed, it's more like an electronic tug-of-war. It makes listening to music a lot more enjoyable, however it works.
Thanks for the reply.
Re:I should have patented it... by Ian+Wolf · 2004-03-15 15:06 · Score: 1

I couldn't agree more. I've actually invested a lot of money in making my systems quieter. On both of my workstations, I replaced the loud sleeve bearing fans with quieter ball bearing fans from Vantec. I then bought "Silent" (aka Quieter, but still pretty loud) Power Supplies, and a great little CPU cooler from Zalman that really is extremely quiet. To take it a step further, I made a simple fan speed controller so I could turn them down when I wasn't working the machines very hard. It was a lot of work, but its significantly quieter in my home office.

Next on my list of things to fix is my network switch, which sounds like a propjet on takeoff. The thing has three really loud fans that I can hear clearly from the next room.

I really hope this guys idea takes off.

--
"The words of the prophets are written on the Slashdot walls."
Re:I should have patented it... by Anonymous Coward · 2004-03-15 15:08 · Score: 0

Do you thin you wil ever lear to spel 'though' correctl?
Re:I should have patented it... by Jim+Starx · 2004-03-15 15:15 · Score: 1

Playing low music to cover up another sound isn't what we're talking about, we're talking about essentially deleting sound waves from the air.

--
The darkness... controls the music. The music... controls the soul.
Re:I should have patented it... by Cosmic_Hippo · 2004-03-15 15:24 · Score: 2, Informative

Oops, I re-read my post and realized I screwed up on one point. The speaker output isn't zero. The combination of the ambient sound and speaker output at the ambient sound frequency should be zero.
Re:I should have patented it... by layingMantis · 2004-03-15 15:25 · Score: 1

that's what it was doing...hence my use of the word "cancel", not "drown out".

~mantis
Re:I should have patented it... by bcrowell · 2004-03-15 15:27 · Score: 2, Funny

The experience I've had with the equipment in class showed that the noise cancellation circuitry recorded the original sound wave, inverted it and fed it back into the speaker. The combination of positive and negative voltage basically told the speaker to output zero signal for that particular frequency. Nothing is destroyed, it's more like an electronic tug-of-war. It makes listening to music a lot more enjoyable, however it works.
I think what you're saying would be a good approximation if the distance between the two speaker diaphragms was much smaller than a wavelength of sound. In reality, the wavelength of audible sound is on the order of 10 cm, and although the distance between them may be somewhat less than that, it's still probably at least a cm or so. So here's the situation. The original speaker spews out sound in all directions, that sound has energy, and only some of that energy impinges on the second speaker. For the energy that impinges on the second speaker, it is at least theoretically possible for it all to be absorbed as mechanical work, and converted into heat and electrical energy. But the rest of the sound was radiated in other directions, and has existed for a millisecond or something now. If you cancel that sound, you're doing it "in flight," so there's no physical mechanism for expending it as mechanical work; it has to come off as radiated sound in other directions.
Then again, I could be totally wrong, like I was in my reply to your first post.
No testicles need to be wagered :-)
Oh good -- I'll put away the exacto knife, then :-)

--
Find free books.
Re:I should have patented it... by sjames · 2004-03-15 15:36 · Score: 3, Informative

I was obviously wrong in my prediction about an audible noise for people not wearing the headphones, but I'll bet both my testicles that it's not because conservation of energy is violated. You'd get the Nobel Prize if you found a violation of conservation of energy.

Your bloodline is safe :-) I'm guessing the energy is dissipated as heat in the speakers and voicecoils themselves. The cone will travel further than normal since it will be 'flowing with' the incoming pressure waves rather than working against the air as normal.

As you say, there's only a small amount of power in the small zone where the sound is deadened, so not all that much extra heat in the speakers.
Re:I should have patented it... by Cecil · 2004-03-15 15:39 · Score: 2

BYU is prestigious? It looks to me like a religious school tightly associated with the Church of Latter Day Saints, and I would personally consider any research that comes out of it a little bit suspect. But maybe that's just me. Do they have a good history of acclaimed scientific pursuits?

--
Random and weird software I've written.
Re:I should have patented it... by slimak · 2004-03-15 15:45 · Score: 1

That sounds more like a noise mask than a noise cancelation (unless you had recorded and inverted his snores, and he snoked exactly the same all the time).
Re:I should have patented it... by Jim+Starx · 2004-03-15 15:55 · Score: 1

Music can't cancel snoring. It can drown it out and maybe your mistaking that for cancelling, but it's not the same thing, trust me.

--
The darkness... controls the music. The music... controls the soul.
Re:I should have patented it... by Anonymous Coward · 2004-03-15 16:13 · Score: 0

with the Church of Latter Day Saints

never heard of that church before... you probably meant The Church of Jesus Christ of Latter-Day Saints.

I would personally consider any research that comes out of it a little bit suspect

a little bit suspect eh?.... that's interesting...
Re:I should have patented it... by FallLine · 2004-03-15 16:26 · Score: 3, Interesting

Well I'm no PhD in physics, but I (did stay at the holiday inn express last night^H^H^H^H^H^H^H^H^H) do own a QuietComfort2 headphone set. I would agree that there is no discernible noise coming from outside the earphones. I suspect the explanation though is relatively very simple (or perhaps I'm just naive). The earphone cup is already quite muffled. The noise cancelling circuity only needs to "cancel out" a tiny amount of noise, that which would reach your ear by leaking through the insulation. Whatever noise is created by the cancellation speaker is quiet relative to outside background noise and will be further muffled by the headset before someone sitting next to you can hear it. In other words, whatever background noise you'd hear without the headphones is almost certainly (in real world applications) going to be orders of magnitude louder to a neighbooring passenger than the noise coming through your earphones.
Re:I should have patented it... by rnelsonee · 2004-03-15 16:28 · Score: 1

Sorry to butt in, as it looks like you've guys got this problem figured out. But I've got a similar question. The active noice-cancellation that's used in the device this article mentions involves sending a sound wave into the sound coming out of the fan, right? Since energy is being conserved and "equal and opposite reaction" stuff, wouldn't the speaker that creates the cancellation waves have so send compression waves in the opposite direction (now travelling the same direction the sound waves from the fan would've made)? If air is being pushed forward, there must be some force pushing backward (either that, or the device will accelerate). Since it's probably secured to the PC frame, does the sound energy go there? I'm just thinking that the energy goes into the case, but for whatever reason (density changes possibly) the sound changes frequency. It's got to change frquency, or else we'd still hear it. Or can that energy be transferred into the floor/desk somehow? Just trying to figure out where this energy is going....
Re:I should have patented it... by AssProphet · 2004-03-15 16:53 · Score: 0

man I wish that wasn't the first thing people thought of when they had a good idea. How about instead of "I should have patented it, you say, I should have produced it. It annoys me so much the way people think "patent camp" is a perfectly acceptable practice justified under capitalism.

Patents stunt progress, it's too bad people are often more interested in their own wellfare than that of others. This applies both to those who patent things, and those who steal ideas and take the credit.
Re:I should have patented it... by Cuthalion · 2004-03-15 17:46 · Score: 1

Conservation of energy says you can't just destroy the energy of those sound waves

No, but you can definitely turn it into heat.

--
Trees can't go dancing
So do them a big favor
Pretend dancing stinks!
Re:I should have patented it... by cgenman · 2004-03-15 18:11 · Score: 1

Is the effect of noise cancelling headphones more pronounced than, say, the effect of wearing a traditional pair of big muffley things?

I'm thinking about getting one for my girlfriend's subway commute, but I haven't tried a pair since the very, very early (read, bad) days.

--
The ______ Agenda
Re:I should have patented it... by hemholtz · 2004-03-15 18:17 · Score: 1

too late. i already own a device like this. nelson pass came up with the phantom acousics shadow decades ago to cancel standing waves in high end audio systems. it too has a mic amps and speakers to cancel out bass modes on room boundries. i think nelson has some patents on it but not sure how specific. the basic priciple is the same just a little different application.
Re:I should have patented it... by xtal · 2004-03-15 19:44 · Score: 3, Interesting

You'd get the Nobel Prize if you found a violation of conservation of energy.

Not mine, but.. compelling.

Casimir Effect

--
..don't panic
Re:I should have patented it... by It'sYerMam · 2004-03-15 20:03 · Score: 1

This was, in fact, thought up by daedalus and was detailed in his book, The Inventions of Daedalus. It was his plan to fit it to jet engines to cancel the noise from them.

--
im in ur .sig, writin ur memes.
Re:I should have patented it... by shadowmas · 2004-03-15 21:00 · Score: 1

i remember seeing this kind of technology on discovery channel several years (around 99 i think). they fixed speakers to a car exhaust pipe and and played a inverted form of the noise that they captured using a microphone. it also showed the same technology used to reduce vibration. from what i remember the equipment used were just basic speakers and stuff the only difficult part is predicting what the noise will be like in the next moment using past data.
Re:I should have patented it... by rokzy · 2004-03-15 21:18 · Score: 1

the Casimir effect is based on the uncertainty principle, which doesn't violate conservation of energy - it just gives the universe an overdraft in case it's been spending a bit too much.
Re:I should have patented it... by rishistar · 2004-03-15 23:08 · Score: 1

Well the other thing to take into account is that the sound forms a field. So the level of cancellation can vary depending on where you are relative to the sound source and the noise cancelling speaker.

--
Professor Karmadillo Songs of Science
Re:I should have patented it... by Lumpy · 2004-03-15 23:44 · Score: 1

recording the noise, computing the negating and sending it off) of noise.

it's not nearly that hard. it's called an inverting amplifier and a delay line.

you need the delay line to match things up so that you are creating the anti-sound at the right time. if you made t he whole thing small enough and mounted the speaker on top of the fan a $0.05 741 op amp would do the trick without any special or custom anything.

Been there, did it in college EE class you can cancel most of the noise without specalized gobblety gook.

--
Do not look at laser with remaining good eye.
Re:I should have patented it... by handorf · 2004-03-16 02:45 · Score: 1

IANAP, but the two signals are directly off phase so the net result should simply be a pressure increase. Since the body deals with pressure increases all the time, it just ignores it.

Unrelated... a very common place to find Active Noise Cancellation is in aviation headsets used in small airplanes like these.

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-- IANAEG - I am not an elder god.
Re:I should have patented it... by Mr.+Competence · 2004-03-16 03:14 · Score: 1

Actually, it is consistantly ranked one of the top universities in the nation. It's Law and Managment schools in particular are internationally ranked. Here is some data from the Mariott School of Management:
U N D E R G R A D U A T E

RANK
PROGRAM
SOURCE

3rd
Accounting
Public Accounting Report, 2003

36th
General Management
U.S. News & World Report, 2003

G R A D U A T E

RANK
PROGRAM
SOURCE

1st
MBA (payback)
Business Week, 2002

17th
MBA
Forbes, 2003

World 26th
MBA
The Wall Street Journal, 2003

29th
MBA
U.S. News & World Report, 2003

World 75th
MBA
Financial Times, 2004

3rd
MAcc
Public Accounting Report, 2003

57th
MPA
U.S. News & World Report, 2001

33rd
Entrepreneur
Success, 2001

--
Those who open their minds too far often let their brains fall out.
Re:I should have patented it... by thefinite · 2004-03-16 03:27 · Score: 1

I am a BYU student and while we are no MIT, our science programs certainly aren't slouches. My brother is a Chem E PhD candidate here working on nano-sized batteries. He isn't the only person in the world doing it, nor is he making earth-shattering advancements, but he is contributing to the field. Like most LDS people, he has a career in which he wants to do good things. Wikipedia says some higher education mag ranked it as the best place to turn research dollars into inventions.

Two other questions: Why would a religious affiliation make you think BYU's achievements are suspect? That seems a bit presumptuous to me, I guess. Secondly (not that you aren't a generally insightful person), but why in the world did you get an "Underrated" mod? (I guess that is a rhetorical question.)

--
Boom Shanka
Re:I should have patented it... by Anonymous Coward · 2004-03-16 03:41 · Score: 0

While I only have a mere bs in physics I thought I might point out that statements about conservation of energy are only valid in closed systems. If the system is open and energy flows into or out of the system then relative to the system energy has been "created" or "destroyed".

Active noise cacellation by definition involves introducing energy. The added wave is carefully modulated so that the energy input is "negative". (negative energy? How can that be?! The negative term is only meaningful in relation to the sound wave summation. 'Zero' sound is still positive air pressure. If you're concerned consider spending energy to start air molecules moving then spending more energy to grab them and hold them still again.)

In fact, in this open system, entropy is negative - a number of waves with a random magnitude (given arbitrary noise) have their magnitudes re-set to zero. Uh - except I'm not sure weather to talk about particles with velocities or waves with magnitude. Anyway, this sort of thing is possible in a system that is not closed. Negative entropy happens in open systems all the time. That's why it takes so much energy for me to clean my apartment.

Anyway this is starting to ramble, but I wanted to question the validity of making energy conservation statements, since the batteries in the noise cancelling headphones are acting on the system.

Adam T
Re:I should have patented it... by Anonymous Coward · 2004-03-16 03:57 · Score: 0

I read a book about the case of the forger who ended up murdering half a dozen people, to cover up his forgeries.
The author quoted one of the detectives who worked on the case, who said something like, "Utah is the fraud capital of the USA". Why? The author said that if an elder was on the Board of Directors other LDS types would, suspend their critical faculties, and fall for it.
This young LDS man made a hobby of buying and selling old documents. He started to specialize in old documents that would be of interest to his co-religionists. And he started to fill this niche through forgery.
He used his knowledge of rumors of embarrassing documents to forge documents with contents so embarrassing that devout Mormons wanted to buy them up, and seal them away, and would not submit them to outside document experts, to verify their authenticity. The contents were too embarrassing.
Re:I should have patented it... by Cecil · 2004-03-16 04:04 · Score: 1

I am a BYU student and while we are no MIT, our science programs certainly aren't slouches.

Well that's good to hear. Personally I don't really think MIT is all that leading these days anyway. They've been spending way too much time pandering for government and industry grants.

Why would a religious affiliation make you think BYU's achievements are suspect?

Well I admit my initial impressions were incorrect. I wouldn't have asked for replies if I didn't want to get the real story though.

Besides, it's not so much that the religious affiliation itself makes things suspect. I just found it curious that an institution which intentionally limited itself to a relatively small subset of people could also be a leading research university. But it's not really that strange now that I think about it. A more specific charter will attract people from all across the country/world who believe in it, whereas most universities are inherently limited geographically or by field.

Your well-reasoned response has opened my mind a bit, thanks.

P.S. why in the world did you get an "Underrated" mod?

I have no idea. Ah, Slashdot moderations. One of the few things that's even more arguable than religion. :)

--
Random and weird software I've written.
Re:I should have patented it... by Anonymous Coward · 2004-03-16 04:23 · Score: 0

I just found it curious that an institution which intentionally limited itself to a relatively small subset of people could also be a leading research university.
It's actually easier to get into BYU if you're not a member of the LDS church. You still have to agree to abide by their standards for grooming, chastity, etc, but you're pretty much a shoo-in if your grades are okay. They try to get as much diversity as possible, and since not many people apply that aren't LDS, those that do have a good shot.
Re:I should have patented it... by CProgrammer98 · 2004-03-16 04:31 · Score: 2, Interesting

I remember many many years ago (> 20) reading a sci-fi story about a noise cancellation device that work in exactly the way current real devices do. The plot of the story was based around "where does the energy go?" The author concluded that it would be stored in the powersource of the noise cancellation device. As I recall correctly, the fictional inventors of the device discovered this at the conclusion of the story when the device exploded - the battery ended up storing all the energy until, as Scotty would have said "She canna take any more cap'n" and the whole thing blew up spectacularly.

If anyone can remember the name of the story or even the Author, I'd be very grateful...

--
And the people shall be oppressed, every one by another, and every one by his neighbour Isaiah 3:5
Re:I should have patented it... by smithmc · 2004-03-16 04:48 · Score: 1

Conservation of energy says you can't just destroy the energy of those sound waves. Most likely you're just sending extra-strength sounds waves somewhere else. Theoretically the extra energy could be converted into heat, or electrical energy, but I doubt that's really practical.

The extra energy is being converted into heat energy, as it strikes and is absorbed by the backs of the ear pieces, the ear padding, etc. Bear in mind that we're talking about a really small amount of energy, here.

--
Downmodding is the refuge of the weak. Don't downmod, make a better argument!
Re:I should have patented it... by mwood · 2004-03-16 05:09 · Score: 1

Um, I wonder if Tom Swift, Jr. already has a patent on active noise cancellation. OTOH it's probably expired by now...that was an awfully long time ago.
Re:I should have patented it... by Eraser_ · 2004-03-16 06:10 · Score: 1

Well, I do have a PhD in physics

normally only a gazillionth of a watt

Which SI unit is a "gaz" again? :) I must have missed that in my introductory physics course.
Re:I should have patented it... by mdielmann · 2004-03-16 06:20 · Score: 1

Yep, noise cancellation headphones are like playing environmental sounds, but right near your ear. If you equate it to regular headphones, if you can barely hear conversations around you, they can barely hear what your headphones are playing. When the environmental noise is louder, the headphones play louder too, but it's still hard to notice due to all the environmental noise. From an outsider's perspective, they would be very quiet.

--
Sure I'm paranoid, but am I paranoid enough?
Re:I should have patented it... by tiger99 · 2004-03-16 06:23 · Score: 3, Interesting

No, the cancellation can only be partial and in certain positions. The problem is simply a matter of time delay, the speed of sound is not very high so for practical dimensions there is substantial phase shift. By using a lot of speakers and very complicated processing, you can make it better, but it is still in the form of an interference pattern, and will always show peaks in certain places. You would need to make the summation of the speakers look like the original source, but in antiphase, to everyone around, to get cancellation. The wavelength of sound at 1KHz is about a foot, if you use one speaker you need to get the difference in disatnce between everyone and the speaker very much less than 1 foot so they all see cancellation. The idea is to put the maxima where they do least harm. These systems only work on regular frequencies, you can't predict random noise, and so can't cancel it unless maybe the speakers are all very much nearer people than the original source so there is time to do the computation.
A very greatly hyped and over-rated technology, which in some specific circumstances will provide a useful reduction (10dB?) in low-frequency noise, for example in the Dash8-Q400 aircraft, where propeller blade fundamental frequency noise is at 85Hz in the cruise (6 blades at 850 rpm, which is lower than most), and where people tend to sit in predictable places, it does quite well, although a fair part of the reduction is by trimming the relative phases of the two propellers (which should run in synchronism in steady flight, although this is not a safety-related function and might not always work, as it is not provided with any backup system), how that compares to the contribution from the speakers I don't know. The active noise suppression system can command the propeller controls to adjust the phasing, and indeed select which blades to synchronise, as they might be slightly unequal, of course it has only extremely limited control authority to avoid it becoming safety-critical, so it can only trim the relative angles very slowly. That is basically adjusting two noise sources so they make the least overall noise, inside the aircraft. I always had the suspicion that at certain precise positions outside (as presumaly happens with all twin-engined aircraft), the noise would be doubled, but it passed certification so it must have been acceptable. Probably much quieter than the average jet, Avro 146 excluded, anyway.
At 85Hz, the wavelength is about 12 feet, so the problem is somewhat simpler, but still very complex....
I am not a noise expert, but I can clain very intimate knowledge of the propeller sync system, called "syncrophase" in this case, being one of its main hardware designers. The propellers are synchronised at the desired angle, within about quarter of a degree, which is not bad considering there is no mechanical connection, the engine power is several thousand horsepower, and only a little pulse as each blade passes a sensor gets sent from the master controller to the slave. Oh! sorry, I forgot, can't use these words any more..... Back to the drawing board. Ground the aircraft in the interests of political correctness. Now, did it have any IDE drives on board?
On a jet, by comparison, the fundamental frequency is much greater, and the engines can't be synchronised anyway, so these systems are not worth bothering with.
Re:I should have patented it... by HeyLaughingBoy · 2004-03-16 06:51 · Score: 1

Wow!! I'm not the only one to remember this story. OK, so I remember the things he was trying to silence were called "screaming meemies", but what was the name of the book. IIRC it was the first Tom Swift book I read, age 11 or so...
Re:I should have patented it... by majestyk2000 · 2004-03-16 07:01 · Score: 1

"If anyone can remember the name of the story or even the Author, I'd be very grateful..."

How about "Tales from the White Hart" by Arthur C. Clarke? First story therein is titled "Silence, Please!"

Google rules, booyah!
Re:I should have patented it... by mwood · 2004-03-16 07:15 · Score: 1

Looks like #26 -- _Tom Swift and his Sonic Boom Trap_, according to http://users.arczip.com/fwdixon/tomswift/

First MIT is building soldier suits to do vision what Tom's "invisible" sub did to sonar, now this. All we need is a working repelatron and some Space Friends and we're there.

For the rest of you: one of a series of novels published back when knowing stuff was still cool and kids wanted to become famous scientists rather than strung-out rock stars. (See also Danny Dunn, _There's Adventure in $nameyourfavoritescience_, and countless others.)
Re:I should have patented it... by kmac9704 · 2004-03-16 10:48 · Score: 1

the amount of energy impinging on them is normally only a gazillionth of a watt

Did your PhD dissertation show that the unit for energy was not in fact the JOULE, but was instead the watt? I'm sure you could get a gazillion Nobel Prizes for that proof.

P.S. If I said your testicles didn't apply to the conversation, would you accuse me of violating them? I sure hope not...
Re:I should have patented it... by Anonymous Coward · 2004-03-16 13:38 · Score: 0

pshh, duh!
Re:I should have patented it... by lkeagle · 2004-03-16 21:27 · Score: 1

I'll ride my B.S. in physics in on the coat-tails of the PhD.

It is true that the energy levels we are dealing with are miniscule. However, if they can be heard by your ear, they can be heard by others. There are several ways that sound waves lose intensity -- not energy. The most obvious is dispersion. Sound follows the distance-squared law just like any point-source radiation (we'll ignore that a speaker has area, and is therefore not a point-source. If you really wanna see scary math, I'll show you some area or volume-source sound fields). So if you want the sound to be less intense, easy... Just get further away from it.

The next method of sound reduction is absorption. This is when the sound energy causes something to vibrate, transferring energy into heat. Normally, as in those foam coverings we see on studio walls (or around your headphone earpiece), the sound energy is trapped inside the small pockets of air that make up the foam or fiberglass sound insulation, and simply bounce around inside until the energy eventually gets dispersed into the solid material of the foam itself.

The next method of sound reduction is reflection. Of course, this does nothing to actually get rid of the energy, but rather channels it away in another direction. Remember though, there is no such thing as a perfect reflector. Every reflector will absorb a tiny bit of energy from the source wave.

So the reason you don't hear the output of the headphones if you're not wearing them is because almost all of the sound energy is trapped between the ear and the speaker and simply bounces around in there until it is all either absorbed by the headphone casing or your own flesh. Of course, if you got right up next to the headphones, I'm certain you could hear plenty of sound being generated by the vibration of the headphone casing itself.

What we should all realize about this particular application is that the sound source is almost purely periodic. The only part of the fan noise that can't be predicted is the chaotic sound created by the turbulence of the air at the tips of the fan blades. This means that through some 'simple' correlation techniques, the fan noise can be sampled and an exact cancellation source can be calculated -- for a given listening location. This is unlike the headphones application, which has to deal with computing a large variety of random audible noises. You'll probably notice that the ability of these devices to cancel sound is limited to a certain bandwidth of the middle range of human hearing, and even then only by about 10-15 dB at best. It will work fairly well on the lower frequencies, but will rely almost completely on the mass of the headphone casing itself to block the higher frequencies from reaching your ear.

The most interesting part of this problem from a physicists point of view will be how to get around the doppler effects of sampling and reproducing a waveform in a moving airstream. Also, fans don't produce a steady stream of air -- rather, they produce a pulsing stream of air that varies depending on your location in front of the fan. Any musician that's tried to practice in a room with a ceiling fan will understand that frustration. I suppose that whatever software you use to calculate a cancelling waveform can be used to perform those calculations as well.
Re:I should have patented it... by layingMantis · 2004-03-17 15:01 · Score: 1

Music can't cancel snoring......in other words:

Sound can't cancel sound?

But actually, that's what this article is about: sound waves cancelling other sound waves. Is the concept of a music speaker doing this hard for you to fathom? By pointing my speaker in the right direction (at his head, roughly), the low frequency waves it emitted were able to cancel (not mask, not drown out) his snoring to such an extent they were hardly audible at all. When said speaker was not pointed in the right direction, the snores immediately became fully audible again despite the low music.
Re:I should have patented it... by Jim+Starx · 2004-03-17 16:23 · Score: 1

I didn't say sound can't cancel sound, I said music can't cancel snoring, because they're not the same sound. Your not grasping the physics behind this. For sound to be able to cancel sound you have be playing an exact copy of the original sound with the phase inverted.
Look at like this. Think of sound as a number, your roomates snoring is a 3, your music is a 400. When you add them together you get 403, your brain is just rounding to 400, which is why you hear the music and the snoring doesn't bother you. What this article is talking about is playing a -3 over the 3, so you get 0. That's probably not the best way to explain it but I'm not sure how to simplify it more.
Reread the article, this is why they mention small microphones. The sound has to be captured so an inverted copy can be fed to the speakers. If what your saying worked them technically if you point a speaker and play music at my head it will cancel out my voice, this just isn't true, people talk over music all the time, just think about it.

--
The darkness... controls the music. The music... controls the soul.
Re:I should have patented it... by layingMantis · 2004-03-17 17:09 · Score: 1

"cancelling" a sound is just a matter of interfering destructively with the sound waves that comprise it. When this happens, the amplitude (the loudness) of the resulting waves is reduced - even if the speaker waves aren't *exact opposites of the snore waves. The speaker is emitting soundwaves at *many frequencies/phases, and some of those waves are at such a frequency/phase as to interfere with the snore waves emitted by the roommate. It is not necessary for the speaker waves to be exact copies for some interference/cancellation to occur. Your number analogy only confuses things: is that number a frequency or a loudness?? You use it as a frequency by saying that 3 + -3 = cancellation. But then you also claim that "3" is less noticeable than "400" - which isn't logical if these are frequencies. This music was very low volume, in any case. And if I am wrong, and no cancellation is occurring, then how would you explain the increase in noise level if the speaker wasn't pointed at the snore source (an abrupt, noticeable increase) ?
Re:I should have patented it... by Jim+Starx · 2004-03-18 05:04 · Score: 1

how would you explain the increase in noise level if the speaker wasn't pointed at the snore source (an abrupt, noticeable increase) ?
If you point the speaker at him then you are hearing reflections coming directly from his head. Your brain can diffrerentiate sounds based on their locations, it's called the cocktail party effect; if the music and snoring are coming from the same location then your brain has a harder time seperating them making it easyer for one to overshadow the other. As for it being an "abrupt, noticible" diffrence, I'm inclined to believe that your brain is tricking you into hearing something you want to hear.
I meant the number to represent amplitude with a negative number being the inverse phase of that amplitude. Like I said, it's not the best way of explaining things, I'm aware of that, but I'm not sure how else to explain this to you. You are right in that music is many diffrent frequencies at many diffrent phase coherencies with respect to the snoring. But cancellation only occurs if the phase is 180 degree's out of sync and the amplitudes are equal, the more you deviate from that the less it cancels at an exponentially increasing rate. You have to be so close your effectively equal for the sound to be audibly canelled. Otherwise your only cancelling part of the sound and your brain can add in the missing pieces, it'll just sound a little phasy, it won't be audibly lower. Your right in that some cancellation is probably occoring because of the music, but it's purely random, statistically rare, and practically speaking cannot be enough to cause an audible difference.
I can't press on you enough that the sounds have to be as close to an exact inverse as possible. Just think about it man, if sounds didn't have to be so close we couldn't have music because the instruments would all be cancelling each other out, we couldn't talk to people in a room because more then one voice at a time would cancel out. Your brain automatically weeds out alot of what your hear, you need to seperate that type of psychological cancellation, that takes place inside your head, from the physical cancellation that can occur with the sound waves. This article is talking about the latter, your technique employs the former. I can understand how it can appear to be the same, but it's not.

--
The darkness... controls the music. The music... controls the soul.

Wow by michaelhood · 2004-03-15 13:34 · Score: 3, Interesting

Active Noise Cancellation stuff is a really cool technology. I wonder if this could be applied to cars and other "larger louder" things in the future.

Re:Wow by crackshoe · 2004-03-15 13:37 · Score: 5, Informative

Its actually used on some heavy earthmovers and tractors simply because its actually cheaper than making a decent muffler.

--
Don't worry - its just stigmata. Pass me a napkin and don't you dare tell my mother.
Re:Wow by Martin+Blank · 2004-03-15 13:37 · Score: 4, Funny

Maybe on the inside. On the outside, they're already quiet enough that I miss when they're coming up behind me.

Damned cars always trying to stalk and eat me.

--
You can never go home again... but I guess you can shop there.
Re:Wow by SEWilco · 2004-03-15 13:38 · Score: 3, Funny

Excuse me, what did you say?
Re:Wow by krosk · 2004-03-15 13:55 · Score: 5, Interesting

Most car noise these days is not from the engine running. Technology these days allows new cars to run incredibly quiet. Probably 99% of the noise you hear while traveling down the highway is road noise. Noise produced from your rubber tires against pavement. I saw a news flash a couple years ago about a new type of pavement that dramatically reduces that noise, but it's too expensive to be widely used.
Re:Wow by afidel · 2004-03-15 14:08 · Score: 2, Interesting

But in this case it's absolutly retarded. For only $17 MSRP you can get the Arctic Cooling Silencer64 which is designed to handle any AMD Opteron/Athlon64 currently shipped and produces only 20dB of noise (essentially silent). It achieves this through a large, slow fan which also has the advantage of being more reliable =)

--
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Re:Wow by Cornelius+the+Great · 2004-03-15 14:18 · Score: 3, Interesting

"Active Noise Cancellation stuff is a really cool technology. I wonder if this could be applied to cars and other "larger louder" things in the future."

The 2003 Dodge Viper SRT/10 has side exhaust with active noise cancellation. It can be switched on/off to allow for "stealth mode" or a throaty sound- though I can't imagine why... I love the sound of a V-10.

--
Sigs are for losers
Re:Wow by Anonymous Coward · 2004-03-15 14:26 · Score: 0

So that way, when your engine is doing something bad, you cant even hear it! It seems like a great idea on the surface, but if it can cancel out all engine sound, I bet you wouldn't notice half as many problems with your car until its too late.
Re:Wow by Genda · 2004-03-15 14:39 · Score: 4, Insightful

Actually it has been used in a variety of applications for some time. Back in the 70s a huge diesel generator had mikes place on it, then further out was surrounded by large speakers. The mikes picked up the motors full spectrum and the speakers played it back at the motor. There were two marked effect;
1. The generation room went from deafening to almost whisper quiet...
2. The motor efficiency jump markedly. It seems that one of the significant causes of mechanical inefficiency, is the increased friction due to vibration (both resonant and nonresonant) in the motor. By canceling out that vibration, the motor operated more smoothly, wore out more slowly, ran cooler, and used less fuel.

Of course, at the time, this only made economic sense with huge motors who's cost of maintenance, operation, and replacement justified spending megabucks in improving performance and endurance.

With the new technologies available to produce sound, or damp it in a given space... this technology could be used to improve efficiency and eliminate noise pollution from automotive engines, turbines, and a whole host of noisy machines including the fans in our computers.

I mean, if Bose can do it with your headphones, why shouldn't we do it with our environment...

Genda

- Why are there so few Zen performers? Because it's no fun making a curtain call to the sound of so many people clapping with one hand.
Re:Wow by Tony+Hoyle · 2004-03-15 14:52 · Score: 1

Someone did a neat extension of this where they played with the phasing of the signal to make a speaker which was audible on a dance floor, but completely silent around the sides... no matter how loud they played the music you couldn't hear it at all outside the target zone.

I've never seen it in commercial use, though, so it's possible the technology isn't *that* good.. the TV just made it look like it.
Re:Wow by swordboy · 2004-03-15 15:16 · Score: 1

I wonder if this could be applied to cars and other "larger louder" things in the future.

This was actually on the board for the Dodge Viper. Because of the vehicles 10-cylinder engine, the exhaust note is more like a UPS truck than that of a sports car. The idea was that they were going to cancel the UPS truck noises and add (or simple allow) a more sports car-like sound. I was able to see/hear one of these test cars and it sounded remarkable.

--

Life is the leading cause of death in America.
Re:Wow by RabidOverYou · 2004-03-15 16:37 · Score: 5, Funny

If you reverse the wires, it sounds like a V20.
Re:Wow by michaelhood · 2004-03-15 18:08 · Score: 2, Informative

I live in Orange County. In City of Orange, the 22 at the 55 is *silent*, it's about a half mile of a different type of pavement. When you're driving with the windows down, it goes from a roar to next to complete silence. The parent comment is correct.
Re:Wow by Anonymous Coward · 2004-03-15 19:17 · Score: 2, Informative

Would that be vulcanized asphalt, a concoction of regular asphalt and ground up rubber from used tires? This is something that solves several problems at once. It prolongs road life, because the rubber allows the asphalt to contract and expand easier when temperatures and humidity fluctuates. Even cooler, it repurposes used tires which are piling up around the country.

Naturally, federal and especially state DoTs want nothing to do with this stuff as it has the potential to significantly slash their budgets for road development and maintenence. Yay for politics!
Re:Wow by the+grace+of+R'hllor · 2004-03-15 22:42 · Score: 1

So you're saying he should reverse the phase polarity of aural dampeners, causing the aft exhaust port to emit a higher-powered audio blast at full spread?

Cool.
--
"If you're at a party on the starship Enterprise,
And the karaoke player just plain old up and dies,
Set up a neutrino field inside a can of peas,
Hold onto Geordi's visor and sing into Data's knees!"
Re:Wow by rishistar · 2004-03-15 23:21 · Score: 1

In fact this system is used a lot in turboprop aircraft as well, but going one step further.
The source of the noise is the turboprop fans which then push the sides of the aircraft in/out causing noise (acting as a speaker). So instead of just cancelling the noise you can cause walls to vibrate out of sync to stop the noise being transmitted inside the cabin and as a by products lengthens the life of the wall.

This is the system that uses this technique of cabin quietening systems.

It is different to what is discussed above as the sound field is just being quietened inside the cabin - an enclosed space

--
Professor Karmadillo Songs of Science
Re:Wow by Anonymous Coward · 2004-03-16 00:44 · Score: 0

And what happens if it rains? Depending on the type of asphalt, the water either stays on the surface (leading to high risk of aquaplanning), or is absorbed. Usually, the sound-absorbing asphalt varieties are not rain-absorbing, and vice-versa.
Re:Wow by Anonymous Coward · 2004-03-16 02:07 · Score: 0

[TINFOILHAT]
from the site:

"Microphones

Microphones hidden throughout the cabin continuously monitor cabin noise levels, enabling the system to adapt to changes in flight condition, passenger movement and other transient effects." ...bets on whether their box has an "audio out" port?
[/TINFOILHAT]
Re:Wow by ziondreams · 2004-03-16 02:51 · Score: 0

I wonder if this could be applied to cars...

This has already been done. I read an article once stating that VW would release a car with a system that would record engine/exhaust noise and output the negative waves of that noise through a speaker mounted underneath the vehicle...although now it seems they've chosen an easier, cheaper approach!! :-)

--
01000001 01011001 01000010 01000001 01000010 01010100 01010101
Re:Wow by EddWo · 2004-03-16 02:57 · Score: 1, Funny

Why are you driving on the pavement anyway? Are you trying to run people over? You should drive on the road like everyone else and leave the pavement clear for pedestrians.

--
"Taligent is still pure vapor. Maybe they'll be the last who jumps up on Openstep... "
Re:Wow by Anonymous Coward · 2004-03-16 03:35 · Score: 0

I saw a news flash a couple years ago about a new type of pavement that dramatically reduces that noise, but it's too expensive to be widely used.

We have it all over the Netherlands. It also dramatically increases visibility in rain, adding to safety.
Re:Wow by Anonymous Coward · 2004-03-16 03:40 · Score: 0

Like a Brittney Spears concert. Get rid of that terrible noise, just leaving the jiggling behind (pun most certainly intended.)
Re:Wow by Anonymous Coward · 2004-03-16 03:47 · Score: 0

Wind noise is a large factor as well.
Re:Wow by sameyeam · 2004-03-16 05:22 · Score: 1

They've layed this in a few places here in the UK and it really is quite amazing stuff. It's kinda spooky when you roll onto it off the "normal" road and suddenly there's silence. Well, not silence...but there is a very big difference in the amount of noise.
Re:Wow by krosk · 2004-03-16 09:42 · Score: 1

Interesting that this asphalt is much more expensive, which you would think would lead to a bigger budget for state DoTs at first and as the new rubber asphalt roads become more prevalent, their budgets would slowly diminish. Bureaucracy at its best right? Bureaucrats only looking out for themselves at the cost of billions to the average Joe.
What ever happened to the great nation that I read about in my history books?
Re:Wow by TheLink · 2004-03-19 20:50 · Score: 1

Yah, imagine the amount of noise while they drive on the pavement...
--
- Too many replies beneath your current threshold

Negating Sound? Its like new cars.... by RobertTaylor · 2004-03-15 13:34 · Score: 5, Informative

I have heard of something like that for cars ages ago, basically replays the engine sound over the car sound to negate it.

There were various addons with such a system so you could add a roar of a 911 or rattle of a clapped out sad wanker boy racer in the car.

Jonty! Neil! Work!!

Re:Negating Sound? Its like new cars.... by electrichamster · 2004-03-15 13:45 · Score: 5, Funny

"I have heard of something like that for cars ages ago, basically replays the engine sound over the car sound to negate it."

Alternatively instead of wasting all that money on a sound cancelling system you could just install hugeass speakers, sub and an enormous exhaust pipe, that way no-one will be able to even *hear* the engine noise over all that deafening dance music you'll be playing.
If you feel like it add undercar neons and go-faster stripes for extra style - they're guaranteed to bring the hot chicks from miles around.
Re:Negating Sound? Its like new cars.... by falconed · 2004-03-15 13:47 · Score: 1

There's a guy that lives next door to us with a "clapped out sad wanker boy racer" car. It's the most annoying thing ever to be woken up at 2am by this moron letting his car run for five minutes after he's already parked so he can listen to it. I'd love to install one of these noise cancelling systems without his knowledge so he could hear the engine from inside the car, but we couldn't hear it outside, and see how long it takes him to notice.

--
USE='clever' emerge -u sig
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 14:00 · Score: 0

No, I don't drive a modified 'riced' car, but am tired of hearing dipshits like you
If they didn't run their cars at 2 AM, maybe it wouldn't happen, asshat.
Re:Negating Sound? Its like new cars.... by Skater · 2004-03-15 14:15 · Score: 2, Interesting

For what it's worth - in both of my cars (a Chevy Impala and a Mercury Cougar, both late-model), there's an "auto-volume adjustment". It works off your speed - the faster you go, the louder the radio gets. They are adjustable (one has 3 levels, the other has 7), or the feature can be turned off entirely.

It's a great feature - I find myself messing with the volume control a LOT less. It also doesn't require the technology and expense of sound-cancellation. :)

--RJ
Re:Negating Sound? Its like new cars.... by MayonakaHa · 2004-03-15 14:35 · Score: 2, Funny

Sadly in a lot of places that's true... Of course it doesn't work if you like your hot chicks with at least the intelligence of a pile of rocks.
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 14:39 · Score: 0

I'd love to install one of these noise cancelling systems without his knowledge so he could hear the engine from inside the car, but we couldn't hear it outside, and see how long it takes him to notice.
If he notices he'd probably just swap the wires making it twice as loud. Be thankfull you don't have my problem. The rice boy nice to me had engine problems. His car wouldn't idle smooth. It would rev up and down every seconds. Sometimes he'd leave it running for 10 minutes. Vroom-Vroom-Vroom-Vroom.
Re:Negating Sound? Its like new cars.... by Lord+Kano · 2004-03-15 14:49 · Score: 1

or rattle of a clapped out sad wanker boy racer in the car.

Could you explain this to me. I'm an American.

--
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
Re:Negating Sound? Its like new cars.... by Bombcar · 2004-03-15 15:00 · Score: 1

I believe he refers to the people known as "ricers" or "tuners" who don't even bother improving their Honda Civic's performance, but spend $1000 or more on the fart can and the spoiler.

See here for more info.....

--
Fellowship 9/11
Re:Negating Sound? Its like new cars.... by RedWizzard · 2004-03-15 15:06 · Score: 1

He is probably using a turbo timer.
Re:Negating Sound? Its like new cars.... by jargoone · 2004-03-15 15:26 · Score: 1

I had that feature in a rented car. It was the most annoying "feature" I've ever experienced. Even with the adjustment at its lowest "level", the volume adjustment was not fine enough. It went up in noticable steps rather than gradually.
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 15:50 · Score: 0

Doesn't happen where I live, dipshit.

Maybe if you worked a little harder, you wouldn't have to live in the slums.

Fuck off and die.
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 15:51 · Score: 0

Dance music? Get your priorities straight! These days it's all about gansta rap. Dance music is so mid-to-late 2002.
Re:Negating Sound? Its like new cars.... by debrain · 2004-03-15 15:55 · Score: 1

I have heard of something like that for cars ages ago, basically replays the engine sound over the car sound to negate it.

They had something like this on an Infiniti, I seem to recall, for tire+road noise, so the car was effectively silent as it drove. I think they cancelled the project because they hit more kids playing in the streets who were acoustically (and otherwise) unaware of the approaching vehicle.
Re:Negating Sound? Its like new cars.... by AnalogDiehard · 2004-03-15 16:11 · Score: 1

I have heard of something like that for cars ages ago, basically replays the engine sound over the car sound to negate it.
They tried it on Harley Davidsons and it was a poor seller. Can't imagine why...

--
Eternity: will that be smoking, or non-smoking? I Corinthians 6:9-10
Re:Negating Sound? Its like new cars.... by rpj1288 · 2004-03-15 16:16 · Score: 2, Funny

Wait, how do you know that the chicks will come? DO you have.. experience? You don't belong here! WE do not know of these chicks...

--
Marvin knew: "Think of a number, any number..."
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 17:47 · Score: 0

What year is your Mustang?
Re:Negating Sound? Its like new cars.... by Lord+Kano · 2004-03-15 19:00 · Score: 1

Ok, that trans-atlantic tranlation loses me every time.

I have a project car that is not roadworthy yet, but in addition to some of the things that ricers do (like neon, and maybe ground effect), I'm also going to be putting in a hefty V8 and high performance ignition. Don't worry I think spoilers look stupid, so I'm not going there.

I used to work with a guy who used to tell all kinds of wild stories about him racing (and beating) Vipers and Corvettes with his Saturn Station Wagon. I don't know which was worse, that he told these stories or that he really thought people believed them.

I can't wait leave one of those guys and his four banger sucking my exhaust.

LK

--
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
Re:Negating Sound? Its like new cars.... by paganizer · 2004-03-15 20:57 · Score: 1

Never underestimate the power of the force.

As long as going around corners is not an issue, ANY car can be hopped up.
Example: setting, Centralia, IL 1978. Car: 1974 vega wagon.
Engine: Ford 289ci, Weber750
I helped work on this car, it's whole purpose in life was to be a street racer and seperate idiots from their money. had nice little twists like purposefully mismatched glaspak mufflers and manual spark advance to make it sound like it was barely running.
Until the "frame" twisted, it was pretty much unbeatable.

--
Why, yes, I AM a Pagan Libertarian.
Re:Negating Sound? Its like new cars.... by Anonymous Coward · 2004-03-15 21:02 · Score: 0

you forgot the r-type sticker.
Re:Negating Sound? Its like new cars.... by tgd · 2004-03-16 01:50 · Score: 1

Clearly you've never heard my 911. I just got an 800w amp just to get the stereo loud enough IN the car that I can hear it over the engine, since I have to wear ear plugs while I'm driving.

Its so loud, the kids in the ghetto boomin civics next to me wouldn't hear there stereos over it!
Re:Negating Sound? Its like new cars.... by NeMon'ess · 2004-03-16 03:49 · Score: 1

imagine how many pedestrians will die when fuel-cell cars become popular. hopefully peds will stop just listening for cars and keep their eyes open. they shouldn't be in the street anyway.
Re:Negating Sound? Its like new cars.... by debrain · 2004-03-16 09:48 · Score: 1

The sound being cancelled was, in addition to engine noise, road noise resulting from the interaction between the tires and the ashphault. Fuel cell cars will still have tire noise.

However, I hear they lose the rising pitch we associate with acceleration, so drivers don't have the same queues to their speed.
Re:Negating Sound? Its like new cars.... by Skater · 2004-03-16 13:09 · Score: 1

Really? In both cars I have, it works great. The only time I can hear any variation is if I slam on the brakes - the volume drops noticeably quickly.

--RJ

now for the hard drives by xobes · 2004-03-15 13:35 · Score: 4, Insightful

The noisest part of all my computers i the hard drive, not the CPU fan.

--
- AZ

Re:now for the hard drives by wed128 · 2004-03-15 13:36 · Score: 1, Insightful

i'm sure in theory the technology could be adapted...
Re:now for the hard drives by Anonymous Coward · 2004-03-15 13:38 · Score: 0

I got a new samsung ultra quiet hard drive. It is a lot quieter than my older maxtor drive. By typing

hdparm -Y /dev/hda

the difference is amazing! But doing

hdparm -Y /dev/hdb

And I cant hear any difference. I will soon be getting rid of my old maxtor drive!
Re:now for the hard drives by Anonymous Coward · 2004-03-15 13:39 · Score: 0

Get a Samsung SpinPoint. They're really really quiet and they run cool too. Ok, they're not the fastest - but you'll have to make a compromise.
Re:now for the hard drives by Martin+Blank · 2004-03-15 13:40 · Score: 4, Informative

Pick up some of the new fluid-drive-bearing units most companies are producing these days. I can hear my 60GB drives when they access, but the 250GB drive is completely without any detectable noise.

Of course, I do need one of the prof's nifty new toys for other parts of my system...

--
You can never go home again... but I guess you can shop there.
Re:now for the hard drives by WaterTroll · 2004-03-15 13:42 · Score: 2, Interesting

My western digital hard drive is completely silent unless you put your ear nearby. However, I recall that I could hear a distinct difference in volume when I was using linux or windows 98. it was much audible from a couple feet away while running linux, but completely silent under windows 98. in fact, the first time i ever actually could hear my hard drive clearly (this is all reading/writing data, not the spinning platters) was when i first installed mandrake and used the disk partitioner.
Re:now for the hard drives by IsosAvrio · 2004-03-15 13:53 · Score: 1

hdparm -Y juste puts it in sleep mode. However your post made me RTFM and I really have to thank you. By typing hdparm -M128 /dev/hda the difference is amazing and the performance is the same. However as the FM says, THIS FEATURE IS EXPERIMENTAL AND NOT WELL TESTED. USE AT YOUR OWN RISK Btw, I have a Maxtor. Thanks again
Re:now for the hard drives by Endive4Ever · 2004-03-15 14:17 · Score: 1

In my new PC Server 704 (quad Pentium Pro, redundant power, etc. etc.) the various system fans are so loud that you can barely hear the noisier-than-usual array of 6 Seagate hard drives spin up. I'm still figuring out where that box (size of a two drawer filing cabinet) is gonna fit into the noise equation here.

(It came from the auction (fifteen bucks) with a Red Hat sticker on the front, but I upgraded it to Slackware.)

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Re:now for the hard drives by no+longer+myself · 2004-03-15 14:17 · Score: 1

I did the exact same thing (RTFM) after reading the grandparent... Note to the other curious people, hdparm requires root, so USE WITH EXTREME CAUTION! Other than that, it's fun to learn new tools from slashdot context!
Re:now for the hard drives by nomadic · 2004-03-15 14:29 · Score: 1

The noisiest part of MY computer is the speakers.
Re:now for the hard drives by darkwiz · 2004-03-15 14:36 · Score: 4, Informative

The noisest part of all my computers i the hard drive, not the CPU fan.

How to reduce drive noise:
1. Take your hard drive off the mounts.
2. Find a 3.5" drive mounting kit and a piece of foam (styrofoam, or packing foam).
3. Mount drive on mounting kit, place on top of foam in the bottom of your case.
4. For completeness, ground the mounting kit to your case.

This will knock out a very large portion of your drive noise that is getting transmitted to the body of your case. It is a little Rube Goldberg, but it is very effective.
Re:now for the hard drives by dfj225 · 2004-03-15 14:45 · Score: 2, Interesting

" The noisest part of all my computers i the hard drive, not the CPU fan."

I have one of the new design Alienware towers, and by far the most noise comes from the case fans. I have 2 seagate hard drives, and I can hear them somewhat, but the case fans are much louder. Although the fans themselves don't make that much noise, but the amount of air that they throw around does. If it is quite in the room, the whoosing sound can be quite loud.

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SIGFAULT
Re:now for the hard drives by Trejkaz · 2004-03-15 14:49 · Score: 2, Interesting

The graphics fan is the noisiest component in my case. Those Gigacube Radeon 9600 XT Extremes are damn loud.

I also have a 30-35dBA fan which doesn't help with the noise. To help, I have an Sonata case, and when the case is on, the only thing I can hear is the clicks from the hard drive, and only when it's being used (during loading. Get more RAM if you are using swap!)

Normal operation is silent, or at least silent with respect to the other, louder computers that are not in Sonata cases. :-)

And of course right now the damn thing is quieter than it's ever been while parts are back for repairs. :-(

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Karma: It's all a bunch of tree-huggin' hippy crap!
Re:now for the hard drives by mrm677 · 2004-03-15 15:10 · Score: 1

Interesting you say that your hard drive is louder in Linux and silent with Win98. Could that mean that Windows is doing a better job of eliminating noisy seeks (head movement)?
Re:now for the hard drives by Anonymous Coward · 2004-03-15 15:13 · Score: 0

"new" and "Pentium Pro" do not belong in the same sentence together :-)
Re:now for the hard drives by Endive4Ever · 2004-03-15 15:39 · Score: 2, Interesting

They do in my collection of aging monster hardware.

You can't touch anything else with the reliability and stability of that system without spending four figures today.

And Pentium Pro systems are cool. A good PPro server is like a diesel truck. I can't afford to collect diesel trucks but I can afford to keep around some nice hardware, and even use it.

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Re:now for the hard drives by Kris_J · 2004-03-15 15:49 · Score: 2, Interesting

Get a slower hard drive. 5400rpm drives are nearly silent, draw less power and are much cooler (thus you can turn down other fans). If you're concerned that this will affect your system's performance, you can compensate to some extent with lots of RAM.
Re:now for the hard drives by MichaelGCD · 2004-03-15 16:25 · Score: 1

No no no! It means linux is doing a better job of accessing the hard drive to it's full potential! Microsoft products are inferior on all counts compared to Linux, NO EXCEPTIONS!.

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hate titty pee colon slash slash
Re:now for the hard drives by Anonymous Coward · 2004-03-15 16:29 · Score: 0

The noise is coming from the movement of parts INSIDE the hard drive itself. Mounting it on foam will do nothing.

Invest in a fluid bearing drive if you want something that's quiet. I used to have one of those and it was virtually silent (until I "upgraded" to an older, louder drive).
Re:now for the hard drives by Fweeky · 2004-03-15 16:30 · Score: 1

Look at a Seagate Barracuda 7200.7 or so; they's practically silent (I have 4 of them; an 80G, 2 160G's and a 200G. My ball bearing 80G Maxtor is probably louder than all of them put together. Other new drives are similarly quiet, of course, but Seagate are still regarded as being the quietest. Check Storage Review :)
Re:now for the hard drives by armando_wall · 2004-03-15 16:31 · Score: 1

Interesting you say that your hard drive is louder in Linux and silent with Win98. Could that mean that Windows is doing a better job of eliminating noisy seeks (head movement)?
Windows could be doing a better job not because it is better designed, but because it has more cache assigned. You could decrement Windows cache and thus making the hard disk noisier, and viceversa. This applies to Linux as well (and I guess to every OS with a hard disk cache).
I have two partitions... one with Windows, and the other with Linux. The hard disk is quieter when it is accessing the Windows partition... but this happens no matter what OS is running. For instance, if I access the Windows partition from Linux, the sound is as quiet as when I'm accessing the same partition from Windows.
I guess it has more to do with the distribution of the partition data inside the hard disk. Maybe the disk heads have to move more in one partition than in the other.
Re:now for the hard drives by CyberSlugGump · 2004-03-15 17:34 · Score: 1

Yeah, my IBM 75GXP drive is quite loud with the clicking noise an all. I'd buy a new one, but it would be too much hassel to transfer my mission-critical data to some other drive ;)
Re:now for the hard drives by mabinogi · 2004-03-15 18:09 · Score: 1

I think the point was that the case was acting as a sound board for the noise inside the drive...

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Advanced users are users too!
Re:now for the hard drives by jrockway · 2004-03-15 18:56 · Score: 1

The styrofoam is also a great insulator and should cook your hard drive to death in about 25 to 40 minutes :)

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My other car is first.
Re:now for the hard drives by Anonymous Coward · 2004-03-16 00:41 · Score: 0

I have one question about this. Was this only true with journaling filesystems that have to at least *try* to give some sort of guarantee to metadata or data. Or did it occur regardless of that?
Re:now for the hard drives by ceeam · 2004-03-16 00:52 · Score: 1

Wow. Me: Samsung sv1203n, 5400rpm, set to mid-level AAM, you can hear it only deep in the night. 50 MB/sec still. Next time you think 7200, 10000, 15000 rpm drives are groovy and 5400 are obsolete, think again.
Re:now for the hard drives by Yehtmae · 2004-03-16 01:28 · Score: 0

Really? Maybe for a desktop. But if you've ever heard the noise that a rack of dual xeon servers CPU fans make when they've had to ramp up because your server rooms aircon has failed and the room temp is well over 100 degrees (farenheight), you'd think again! Been there, done that, yesterday in Bangkok!
Re:now for the hard drives by WaterTroll · 2004-03-16 02:34 · Score: 1

Hmm, not sure. I first installed linux with Mandrake 7.1. I believe it had journaling then.
Re:now for the hard drives by Aceticon · 2004-03-16 02:49 · Score: 1

5. When moving your computer remember there's a 3.5" drive mounting kit with a hard drive loose on the bottom of the case - DO NOT TURN THE CASE UPSIDE-DOWN.
Re:now for the hard drives by juhaz · 2004-03-16 03:28 · Score: 1

The graphics fan is the noisiest component in my case. Those Gigacube Radeon 9600 XT Extremes are damn loud.

There are Radeon 9600 XT (well, even up to 9800XT actually) cards with passive cooling, probably bit more expensive than their regular counterparts with small whiny loud as hell fans, though.
Re:now for the hard drives by poot_rootbeer · 2004-03-16 04:05 · Score: 1

Terrible advice. Spinning hard drives can generate a lot of heat, which could easily scorch or set fire to an inappropriate type of foam.
Re:now for the hard drives by mrm677 · 2004-03-16 05:24 · Score: 1

I think you have a good point. I'm guessing that a FAT32 file system has less seeks because the FAT table is cached. Ext2 on the other hand has to traverse Inodes.
Re:now for the hard drives by straponego · 2004-03-16 09:54 · Score: 1

Another data point: I recently bought a Ahanix Silenx 400W PSU from Ahanix. Fabulous PSU, very nearly silent (they claim 14db). I already had a decent CPU fan from Zalman, so after installing the PSU the loudest part of the system turned out to be the Western Digital 120GB drive. It was far louder than I'd suspected; so loud and high-pitched that I think it must have been getting gradually louder over time, which is a little scary. I'd just installed a 200GB Seagate, so I copied my data over and unplugged the WD. The system is very tolerable now. To the point that I won't mess with it anymore until I can get a completely passively cooled CPU/video SFF system. So I highly recommend the SilenX PSUs and the Seagate 200G drives.
Re:now for the hard drives by Christ-on-a-bike · 2004-03-16 12:44 · Score: 1

I doubt that! It was kernel 2.2 back then, no ext3 support (and I don't think Mandrake compiled any other experimental FSs either).
Re:now for the hard drives by WaterTroll · 2004-03-17 07:12 · Score: 1

if yah say so :)
Re:now for the hard drives by darkwiz · 2004-03-21 13:56 · Score: 1

Replying here since there are multiple replies with the same mistake.

To the nay-sayers talking about heat dissipation and styrofoam:

1. What do you think the mounting kit is for? It is for getting the drive off the foam. I (like most people) have a fan in the front of my case. conveniently located directly in front of where my two hard drives are (stacked on top of each other in an old 3.5 inch drive rack). They run significantly cooler, ON TOP OF THE FOAM than when they stood attached to the case directly with no active cooling in front of them.

2. Styrofoam burns at hundreds of degrees. I don't think that your hard drive will ever generate that amount of heat. You'd have to short your powersupply with a thick copper wire and disable the safety mechanisms to generate enough power to burn styrofoam.

Why go through all this trouble? by Zakabog · 2004-03-15 13:35 · Score: 2, Insightful

Why? Can't you just get a really quiet fan? My CPU fan is noisy but I don't care, if I wanted to I could build some sort of box to enclose the noise so I don't hear it. Or I could use water cooling which is much quieter. Or I could put my computer further away from where I am (like in a closet or something, like the box idea.) This just seems like a complicated solution to fix such an easy problem.

Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 13:41 · Score: 2, Insightful

Because we're at slashdot. We don't need working and simple solution - we need cool gadgets, strange hacks and non-working geekythings.
Re:Why go through all this trouble? by Quasar1999 · 2004-03-15 13:50 · Score: 1

Tell that to my employer... There are some of us that are forced to sit beside a bloody loud computer at ear height, and we can't move it anywhere. I might be the minority here, but I'd kill for a quieter PC (and I don't have an employer that would pay the insane price for watercooling my PC just for a little peace and quiet...)

If it's such an easy problem to fix, Why the hell haven't manufacturers fixed it? If it costs sooo little, why wouldn't manufacturers do it, just so they can put an extra marketing bullet on their boxes?

--

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Programming is like sex... Make one mistake and support it the rest of your life.
Re:Why go through all this trouble? by irokitt · 2004-03-15 13:50 · Score: 4, Funny

I have honestly seen computers put in freezers. Keeps it cool and eliminates noise at the same time. Leaves less room for the ice cream though.

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If my answers frighten you, stop asking scary questions.
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 13:52 · Score: 0

Can't you just get a really quiet fan?

Ever seen one that works, for a reasonable price? I haven't.

if I wanted to I could build some sort of box to enclose the noise so I don't hear it.

That'd do wonders for ventilation/heat dissipation, which is the point of having the fan in the first place.

Or I could use water cooling which is much quieter
...and about 10 times as expensive.

Or I could put my computer further away from where I am (like in a closet or something, like the box idea.)

OK, fair enough, but that makes it harder to access the drives and you might have trouble with cables reaching.
Re:Why go through all this trouble? by dalamarian · 2004-03-15 13:58 · Score: 1

Well, considering that the amount of wattage processors now have to disipate to obtain higher clockspeeds, we either have to use higher rpm fans that will only increase in noise or we have to go water cooling. And I am pretty sure that most aren't willing to make that jump, not too mention you still need some fans producing noticeable noise.
Re:Why go through all this trouble? by SillyNickName4me · 2004-03-15 14:00 · Score: 1

Tell that to my dual pIII machine... the whine from that thing is horrible.
Re:Why go through all this trouble? by LinuxHam · 2004-03-15 14:09 · Score: 1

There are some of us that are forced to sit beside a bloody loud computer at ear height, and we can't move it anywhere.

Dude, you, more than anyone need to get a new job. My Dad's cousin worked with a PC next to his head for just 10 years and he's completely deaf on that side of his head. It is extremely damaging to have that kind of noise right next to your head like that. Move. Now. Nothing is worth that.

--
Intelligent Life on Earth
Re:Why go through all this trouble? by soft_guy · 2004-03-15 14:09 · Score: 1

And also you have the noise of the freezer to contend with.

--
Avoid Missing Ball for High Score
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 14:14 · Score: 0

"LinuxHam"? You must be responsible for this thread.

Please refrain from this in the future. Thank you.
Re:Why go through all this trouble? by Endive4Ever · 2004-03-15 14:19 · Score: 1

Put it in an ice chest and hire some lackey to bring in new ice and drain it every few hours.

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Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 14:23 · Score: 0

if I wanted to I could build some sort of box to enclose the noise so I don't hear it. ... like in a closet or something, like the box idea.)

Let's not forget that fans are there to disperse heat; boxing your fan, or your case, might help the noise -- and it will help even more when it quits working after overheating.
Re:Why go through all this trouble? by gilesjuk · 2004-03-15 14:27 · Score: 1

Yeah that's an option in a mid sized case, but in a laptop there isn't always space for a large fan. Smaller fans spin faster to move the same amount of air as a larger fan and that results in high pitched whine. So this would be a useful technology for laptops.
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 14:28 · Score: 0

Your employer won't let you move the computer but they'll let you change the fan? Well why don't you just get quieter fan?
Re:Why go through all this trouble? by kundor · 2004-03-15 14:34 · Score: 2, Informative

A quiet heatsink like this one, perhaps?

While that would be fine, it actually costs more, and it weighs a TON (or at least a thousandth of one, which is nearly as bad.) If this noise cancellation can quiet a system just as much, for the same price, without the potential of ripping a hole in your motherboard, I'd call it a win.
Re:Why go through all this trouble? by Zakabog · 2004-03-15 14:35 · Score: 1

How was this modded down as troll? I am really serious about building a box or using water cooling, or keeping a PC in a closet or using a quiet fan. There are so many things you can do out their that would be far easier than a speaker microphone setup. And what happens when the speaker or microphone fail? Or what if they're not in the right positions (don't they have to be setup perfectly to cancel out the noise?) At least if get a box or put the computer in a closet it's not going to fail, there's nothing to fail heh.
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 14:42 · Score: 0

This reminds me of a friend I know who when 800mhz was the top of the line, he had one and instead of a fan he had a refridgeration unit in his garage, and he ran a pipe from it through the ceiling of his garage through the bottom of his computer an it wrapped around the CPU. It kept it cool and you couldn't here, only downside was you couldn't move it.
Re:Why go through all this trouble? by ckswift · 2004-03-15 14:44 · Score: 1

Get a G5. I'm serious. It is dead quiet.
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-15 14:44 · Score: 0

h aha ha haha !

yes, put your fan in a soundproof box.

how does the air get in and out? hmmmm? bet
that makes a lot of noise going through the vents
to get in there and cool off all the stuff.

what? no vents? have to have some large holes
then -- but that would let the sound out of your
soundproof box.

maybe this is a tricky question, and your answers are just out of your butt?
Re:Why go through all this trouble? by Trejkaz · 2004-03-15 14:52 · Score: 1

The Thermaltake quiet series aren't overly expensive, especially when compared to other companies marketing supposedly quiet fans like Zalman.

Also you can get cases which solve the noise problem to some extent by adding things like filters on the fan grates, rubber gromets on the drive bays to cut vibration, and of course larger case fans (larger fans mean more air displacement with lower fan speed, and high fan speed is generally what causes the noise.)

--
Karma: It's all a bunch of tree-huggin' hippy crap!
Re:Why go through all this trouble? by NecoX · 2004-03-15 15:14 · Score: 1

Bullshit, a regular household freezer CAN NOT handle the heat a computer generates, it would last an hour tops, then break.
Re:Why go through all this trouble? by nahorniak · 2004-03-15 15:18 · Score: 1

Wouldn't the condensation fry the hardware?

--
P.S. This is what part of the alphabet would look like if Q and R were eliminated.
Re:Why go through all this trouble? by Zakabog · 2004-03-15 16:12 · Score: 1

No it wouldn't, you'd need space for the extra speakers and microphones and they'd have to have room so they could be positioned correctly, this is for desktop PCs, besides all the laptops I've used have been quiet enough.
Re:Why go through all this trouble? by gbjbaanb · 2004-03-16 01:41 · Score: 1

who cares about the freezer - I wonder what will happen to the computer as the heat melts the ice around it.... drip.. drip.. drip.. fizz... bang.

So the OP was probably telling the truth - but he didn't mention whether the computer was working anymore :)
Re:Why go through all this trouble? by red_gnom · 2004-03-16 03:06 · Score: 1

"Wouldn't the condensation fry the hardware [in a fridge] ?"

Hot objects inside a fridge should not be covered with condansation. When you bring a cold objects from a fridge to the outside, then they will be covered with condensation water. You can try it with an icepack.
Re:Why go through all this trouble? by Anonymous Coward · 2004-03-16 11:24 · Score: 0

Why the hell haven't manufacturers fixed it?

For the same reason that Commodore didn't put $0.50 head sensors in the 1541 disk drive, or $0.87 UARTs in the C64: because they're cheap

If it costs sooo little, why wouldn't manufacturers do it, just so they can put an extra marketing bullet on their boxes?

Because they believe people care more about the $0.60 the better part would cost than they care about the little marketing bullet.

If you want a quiet PC, buy an HP Deskpro. If you want a cheap POS, buy a whitebox.

Noise and Heat by pholower · 2004-03-15 13:36 · Score: 1, Insightful

It would seem that putting more electronics in the device would only create more heat. Then you would have to increase the fan speed, and then increase the amount of sound cancelation in turn, increasing the fan speed again. An endless cycle. Why not just go with a case that acts as the heatsink?

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-- johntracy.com, because everybody else is wrong.

Re:Noise and Heat by thebes · 2004-03-15 13:39 · Score: 3, Insightful

The amount of heat that a small microphone and speaker generate would be small enough that it would likely be transmitted through whatever the mounting system was made of, into the heatsink itself, and thereby take care of itselt. The heat increase would be negligible.
Re:Noise and Heat by crackshoe · 2004-03-15 13:39 · Score: 1

the speaker, at least, produces next to know heat. A small amplifier wouldn't produce a signifigant amount of heat, but the wattage needed to drive a speaker as loud as the fan (which, as far as i know, is essentially whats going on -- inverting the sound wave and playing it back at the same volume), is almost negligable (i don't feel like doing the math).

--
Don't worry - its just stigmata. Pass me a napkin and don't you dare tell my mother.
Re:Noise and Heat by crackshoe · 2004-03-15 13:42 · Score: 0, Offtopic

next to no. fucking engrish paper eating my brain. this is a bad sign.

--
Don't worry - its just stigmata. Pass me a napkin and don't you dare tell my mother.
Re:Noise and Heat by appleprophet · 2004-03-15 13:49 · Score: 1

The heat generated by the tiny microchip the professor is using can't even be compared to the heat generated by the CPU, graphics card, etc. It is negligible.
Re:Noise and Heat by Anonymous Coward · 2004-03-15 13:49 · Score: 0

An endless cycle
Yay! a perpetual motion machine.
Re:Noise and Heat by Anonymous Coward · 2004-03-15 13:51 · Score: 2, Insightful

Amazing how this simplistic thinking gets modded +5 Insightful. At least explain why you group together a 1 Watt speaker with a 60W CPU. God forbid you actually think the microphone 'electronics' produces more heat since it - well it's more electronics after all.
Re:Noise and Heat by ManxStef · 2004-03-15 14:07 · Score: 1

Why not just go with a case that acts as the heatsink?
What, like the Zalman TNN 500A? Looks very nice but very expensive, though I'm sure it'd find favour in recording studios and the like (when teamed up with a Seagate Barracuda 7200.7 low noise HDD, for instance).

Another link (but be warned, it references Tom's....[new page]...Hardware)
Re:Noise and Heat by Anonymous Coward · 2004-03-15 14:08 · Score: 0

But every time I turn on my Air Conditioner it heats up the house instead of cooling it! Stop the endless cycle of electron on electron violence, which is the main cause of heat!!!!

Same tech as noise reducing headphones by CormacJ · 2004-03-15 13:36 · Score: 4, Informative

I think this is how noise cancelling headphone do it - they just feed the external noise back into the earpieces after inverting it.

Re:Same tech as noise reducing headphones by SpacePunk · 2004-03-15 14:17 · Score: 1

Yeah, used em, very nice. That's what I first thought of after reading the article.

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Steve's Computer Service, Hobbs, NM
Re:Same tech as noise reducing headphones by RedWizzard · 2004-03-15 15:04 · Score: 1

I think this is how noise cancelling headphone do it - they just feed the external noise back into the earpieces after inverting it.
What's new here is that the microphone is very close to the speakers. Normally that would make the system ineffective because as the system cancels the noise, the microphone would detect less noise and stop the cancelling. In the case of headphones (and car noise reduction systems) the microphone is separated from the speakers by a relatively soundproof barrier and so is not itself affected by the output of the noise reduction system.
Probably what is happening here is that the system records the noise of the fan before cancellation, calculates the inverse and then plays that inverse constantly without ever recalibrating. This works because the noise of a fan is a pretty regular waveform. This would explain some of the things the article doesn't, like why air noise isn't cancelled, and why a microprocessor is necessary (rather than a simple inverter circuit).

This would be a lot more useful... by Trolling4Dollars · 2004-03-15 13:37 · Score: 3, Funny

...if it were applied to noise reduction of one's ass after a good bean based dinner. ;p

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Un-news

Re:This would be a lot more useful... by cptgrudge · 2004-03-15 13:53 · Score: 1

Your noise cancellation comes in pill form.
Behold.
Beano.

--
Qualitas edurus commercium, nullus penitus net rimor, nullus deus beneficium
Re:This would be a lot more useful... by Anonymous Coward · 2004-03-15 14:08 · Score: 0

Personally I'd rather have smell muffling...
Re:This would be a lot more useful... by Anonymous Coward · 2004-03-15 15:00 · Score: 0

Does that stuff actually work?

Huh. by dupper · 2004-03-15 13:37 · Score: 5, Funny

When my CPU fan starts to make noise, I just whack my case until it stops.

Re:Huh. by WaterTroll · 2004-03-15 13:47 · Score: 1

it's that damn power supply fan. a nice tap to the top of the case shuts it up. i do it all the time to my friends computers and they yell at me.
Re:Huh. by disntrstd · 2004-03-15 13:59 · Score: 0

You'd be surprised as to how well this method works with women.
Re:Huh. by Anonymous Coward · 2004-03-15 14:13 · Score: 0

I find a bit of superglue in the bearings makes my CPU fan a LOT quieter!
Re:Huh. by rpj1288 · 2004-03-15 14:25 · Score: 1

Heh, try having a ball of cat fur wrapped in the fan. I was wacking that thing all the time. Started to hurt my hand. Thank god that computer's in the basement, where it stays 60F or less, and its such a low end celeron it makes barely any heat.

--
Marvin knew: "Think of a number, any number..."
Re:Huh. by Anonymous Coward · 2004-03-15 14:25 · Score: 0

disntrstd (705189): You'd be surprised as to how well this method works with women.
i dont think that the average /. poster has the arms to manage that, good thing to...
Re:Huh. by austad · 2004-03-15 14:53 · Score: 1

Heh, try having a ball of cat fur wrapped in the fan. I was wacking that thing all the time.

Poor kitty.

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Need Free Juniper/NetScreen Support? JuniperForum
Re:Huh. by Anonymous Coward · 2004-03-15 14:57 · Score: 0

>disntrstd (705189): You'd be surprised as to >how well this method works with women.

>>i dont think that the average /. poster has >>the arms to manage that, good thing to...

I dont thing the average /. poster has a woman either
Re:Huh. by peeping_Thomist · 2004-03-15 15:47 · Score: 1

Why is this moderated as "funny". I do it all the time, and IT WORKS.

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Anything worth doing is worth doing badly -- G.K. Chesterton
Re:Huh. by Anonymous Coward · 2004-03-15 16:00 · Score: 0

When my CPU fan starts to make noise, I just whack my case until it stops.
Excellent! We've got a position for you in our IT department.
Re:Huh. by Anonymous Coward · 2004-03-15 16:53 · Score: 0

Usually it is the case fan or the power supply fan that makes the growling noise. Don't whack your case too hard! I killed a hard drive once by doing that.

Like the noise cancelling headphones? by dealsites · 2004-03-15 13:37 · Score: 1

I thought the noise cancelling headphones worked because they were right against your ears. I wonder how this fan mod works since the speaker is so far away rom your ears. I would suspect that you could be in the position that the fan noise and echo cancelling waves would combine phase and cause even more noise.

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Real-time updates from multiple sources

Re:Like the noise cancelling headphones? by dancedance · 2004-03-15 13:48 · Score: 1

AFAIK you are correct. I am not a physicist, but it seems that any large scale application of active noise cancellation is not feasible because depending on where the listener was there would be no noise, or there would be more noise.
Re:Like the noise cancelling headphones? by Anonymous Coward · 2004-03-15 13:53 · Score: 0

Nope, once the waves cancle they are gone. Headphones cancel all noise because they are next to your ears. This would cancel just the fan noise. You can try this out yourself. Make a mono recording and use a wave editor to invert it. Now point two speakers at each other. First play back with only 1 channel. Then play back with both channels. You will notice it is much quieter with both channels. You still hear something beacuse the phase is imperfect and you get sound leaching from the walls of your speakers. If you were to dampen the sides of your speakers with pillows or something it would be even quieter.
Re:Like the noise cancelling headphones? by Reverberant · 2004-03-15 14:18 · Score: 4, Interesting

I thought the noise cancelling headphones worked because they were right against your ears.
Well yes and no. Noise cancelling headsets are particularly effective because the ANC speaker and microphone are right next to your ears. This helps insure that the signal that arrives at your year can be sampled and inverted so that the sum cancels at the ear. It would be much harder to accomplish this with speakers and/or mics located away from the ear.

However, remote mics/speakers may work if the noise source is highly directional, like a waveguide (I suspect that's happening here). If you can effectively cancel the sound at the orifice, you'll probably achieve a significant reduction in transmitted sound, no matter the location of the receiver.
Re:Like the noise cancelling headphones? by Mysteray · 2004-03-15 14:19 · Score: 1

With a sealed box behind the speaker you could mostly cancel out longer wavelengths from all directions. Longer, that is, than the dimensions of the fan/speaker combo.
It's interesting that he said he could cancel the whine. High frequencies are going to require good alignment of the fan, microphone, speaker, and ear to cancel well. But hey, the guy's a jet engine expert, maybe he knows what he's doing.
Re:Like the noise cancelling headphones? by xs650 · 2004-03-15 14:25 · Score: 1

The wavelength of sound waves at the frequncies of interest is on the order of one foot. The noise emitting part of a CPU fan sort of approaches being a point source compared to that So, it should be possible to place the noise canceling speakers at the fan and do a decent job.
Re:Like the noise cancelling headphones? by Reverberant · 2004-03-15 14:35 · Score: 1

The noise emitting part of a CPU fan sort of approaches being a point source compared to that So, it should be possible to place the noise canceling speakers at the fan and do a decent job.
Well that's only true is the ANC speaker also acts as a point source, and I doubt there's a speaker driver anywhere that's truly omnidirectional. But if you can funnel the noise in one direction, the task becomes considerably easier
.
Re:Like the noise cancelling headphones? by shadowbearer · 2004-03-15 15:10 · Score: 1

If you can effectively cancel the sound at the orifice, you'll probably achieve a significant reduction in transmitted sound, no matter the location of the receiver.

The hell with computers, this would find a huge market among some married people (of both genders *blat*) :)

Sorry, I couldn't resist

*runs*

SB

--
It's old. The more humans I meet, the more I like my cats. At least they are honest.

Bose by Bl33d4merican · 2004-03-15 13:38 · Score: 1

Sounds a lot like those noise cancelling headphones that Bose originated (http://www.bose.com/). Sounds like going to an extreme for a very slight problem...but i certainly give him some Geek points for the project. Then again, I've got very fast drives and they don't make all that much noise...a decent case instead of one of those plastic crappy ones by Dell and Gateway usually helps, too.

--

Every windows user is a sadomasochist.

Re:Bose by automatix · 2004-03-15 13:43 · Score: 2, Informative

Noise cancelling headphones have been around for ages in various forms. Helicopter pilots use them for communication...
The headsets also have 2 microphones in series and out of phase - 1 picks up the voice+noise and the other only the noise, so the noise cancels and you get left with the voice. This stuff is used on comms systems for concerts, etc as well.
Rob :)
Re:Bose by Free_Lard · 2004-03-15 14:07 · Score: 1

at the theatre i work at, an earplug under the headphone of the intercom works wonderfully. people leave their mics on, and about 3 people pick up whats going on onstage at varying volumes, creating a bunch of background noise. the earplugs cancel it out, and you can hear the person speaking.

--
--daniel

pushing is the answer.
pushing will protect you from the terrible secret of space.

Me too! by slifox · 2004-03-15 13:39 · Score: 2, Insightful

I thought of this too, a while back.

The problem is that the fan noise isn't a constant noise and theres no way to create an inverse wave exactly when the sound happens--there will be a delay.

Good to see this concept working though.

Re:Me too! by cybermace5 · 2004-03-15 13:49 · Score: 1

Use feedback. You can use the microphone to determine the major frequencies and then begin shifting the phase experimentally, and measure the change in amplitude. This way the delay is automatically compensated out.

As he said, it works for reducing the whine, which is primarily going to be one frequency. The whoosh is a whole different story because it's basically noise. With headphones, you can deal with it because you know where the sound is going and can do the cancellation processing in the time it takes the sound to pass the microphone and reach the ear. Doing active cancellation at the site of the noise generation is much more difficult, unless you have a ducted sound path like a car exhaust does. Then you know where the sound is going and can place your microphone up the duct to predict what's coming down the pipe, literally.

--
...
Re:Me too! by gosh_d · 2004-03-15 15:21 · Score: 3, Interesting

You're forgetting that sound, being simply a pressure wave, travels a _lot_ slower than an electrical signal (6 orders of magnitude). If the mic is placed closer to the fan than the speakers, the speakers can have plenty of time to invert the signal and replay it. The distance is precisely chosen such that the speakers produce their noise simultaneously with the passing noise of the fan, even though it originated farther away. Delay's not a problem--no predicting needed.

I had an interesting idea based on this (I don't know if it's actually used). Fixing the distance and delay may not be accurate enough to match the signals completely, so you could have a second mic which listens _after_ the cancellation for beats. Superposition of the two similar waves produces the "beats" that musicians use to tune an instrument. By observing the frequency of the beats, the microprocessor could adjust the delay to more perfectly cancel the noise.
Re:Me too! by martensitic · 2004-03-15 17:08 · Score: 2, Interesting

It's true -- most active noise cancellation schema have both a source transducer and a feedback transducer. For instance, most active systems for reducing ductborne HVAC noise (a prime candidate, since in-duct fan noise is transmitted via a controlled, conduit, and the noise comprises fairly constant, discrete frequency characteristics) include a mic downstream of the cancellation "speaker". Feedback from this mic is used along with the source signal to improve the performance of the system as a whole.

--
Ut Tensio, Sic Vis

Re:No need to worry. by hampton · 2004-03-15 13:41 · Score: 5, Interesting

Installing a Zalman HSF is exactly what I did. Highly recommended. Or (and), you can just buy a fan controller for the money (or both) to really quiet down your system.

Where this would be really useful is for the whine of hard drives. It would be far better than the current system of enclosing it in some casing thus making it run even hotter.

How about cancelling out the noise from Lindon? by cheesedog · 2004-03-15 13:41 · Score: 1, Funny

I'd like to place Scott Sommerfeldt next to Darl McBride.

Hey Scott, please take a stroll northword toward Lindon, find the SCO campus, and do your magic.

Real Life Example by fembots · 2004-03-15 13:41 · Score: 0, Troll

Does this method really work?

In real life, if your other half is yelling at you, you then yell back equally loudly, does it cancel the yelling altogether? :)

Having said that, this cancelling method is quite widely used in ancient China (not sure about the modern one). For instance, if you are bitten by a scorpion, just find something equally poisonous, or more, to bite at the same spot, and voila!

--
Rock that crushes, Paper & Scissors that don't matter.

Re:Real Life Example by Martin+Blank · 2004-03-15 13:46 · Score: 1

...

I have failed. Teh Stupid has arrived.

--
You can never go home again... but I guess you can shop there.
Re:Real Life Example by Anonymous Coward · 2004-03-15 13:48 · Score: 0

My next door neighbours used to play their stereo really loud. I'd used my PC microphone and speakers and play the sound back to them (with a 1/2 second delay).
Re:Real Life Example by soft_guy · 2004-03-15 14:12 · Score: 1

I wouldn't be that worried if the scorpian bit me. Instead I'd be worried if a scorpian stung me.

--
Avoid Missing Ball for High Score
Re:Real Life Example by Anonymous Coward · 2004-03-15 14:16 · Score: 0

Yeah, and how many ancient Chinese do you see waslking around these days mr smartypants!
Re:Real Life Example by Professor+D · 2004-03-15 15:15 · Score: 1

I wouldn't worry unless it had been a scorpion.
If you're going to flame for semantics, run a spell checker before you hit "Submit."
Re:Real Life Example by denks · 2004-03-15 17:44 · Score: 1

In real life, if your other half is yelling at you, you then yell back equally loudly, does it cancel the yelling altogether?

Well, if the amplitude is identical, the frequency is the same and the waves are exactly 180 degrees out of phase, then yes they would.

So, the moral of the story:
When your other half starts yelling, start yelling back at the same volume straight afterwards and you may possibly be lucky enough to hear total silence :)

--

I am Monkey, the Great Sage, equal of heaven!

Keep everything quiet by nmoog · 2004-03-15 13:42 · Score: 4, Funny

Thats really cool. Its like those amazing bose noise cancelling headphones.

I have wondered if it was possible to do this in my house. Where I live there is a lot of people who like to scream at each other alot, and it rather gets on the nerves. It would be cool if you could record your neighbourhood noises, and instantly replay them out of phase into your living room. Presto. The beautiful sounds of silence.

Re:Keep everything quiet by electrichamster · 2004-03-15 13:52 · Score: 5, Funny

I wonder what would happen if you placed some huge speakers in a room connected to mic's and some noise cancelling gubbins....would everything just fall silent no matter how loud you shouted?

Could be a useful mute tool for the girlfriend when she goes on too long:

GOD, you're so inconsiderate, you never take my feelings into acco
*click*..........
Re:Keep everything quiet by Anonymous Coward · 2004-03-15 13:54 · Score: 0

You could do that, but you would have to wear a tracker, which would keep track of where you were in your room at all times. Then you would need microphones all over the place, then a few speakers to cancel out the soundwaves as they reached your ears. you would need more than one speaker to take care of the reflections from the walls. It would be damn near impossible to quiet up your whole room at once, since the sound is coming from all over the place.
Re:Keep everything quiet by Anonymous Coward · 2004-03-15 13:59 · Score: 0

Yep, I imagine this would degenerate into one fucking insane mess of feedback, and probably eventually hit the brown noise...
Re:Keep everything quiet by gregmac · 2004-03-15 14:00 · Score: 1

Its like those amazing bose noise cancelling headphones.

Or the same sort of thing, except requires no batteries.

Or with no headgear.

In 1st year university in res, a friend of mine used to sleep with the ear muffs on all the time, they make things amazingly quiet. The plugs are almost as good, but more comfortable to wear.

You can also get special plugs made up by audiologists, that are custom-molded to your ears, and only let certain frequencies through. Musicians use them a lot, for example, bass players standing next to the drums: they get them to filter out all the high frequencies from the cymbals.

--
Speak before you think
Re:Keep everything quiet by nmoog · 2004-03-15 14:06 · Score: 2, Interesting

Dont get me wrong, I love earplugs - I live in a warehouse filled with dudes who love noise music. But Ive tried those bose headphones, and they are amazing. Earplugs DECREASE the noise, the headphones ERASE the noise. That makes a world of difference, especially on airplanes and the like (or offices with heaps of computers) where machine noise can drive you mad.

When you first put those headphones on it freaks you out a bit, because its like being in an anechoic chamber - the noises you use to judge distances (the rooms natural reverb) are cancelled. Its wierd.
Re:Keep everything quiet by afidel · 2004-03-15 14:22 · Score: 4, Informative

Bose noise cancelling headphones suck, they aren't even the best active noise cancelling headphones available. Sennheiser has better models for around the same price. Far better than either though is the Etymotic ER-4P, these in ear canal headphone provide over 24dB of isolation, with some nice jazz playing you won't hear anything outside, headphone.com has them for only $219, about the same as the Bose units.

--
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Re:Keep everything quiet by Jack+Schitt · 2004-03-15 14:38 · Score: 1

It's my understanding that the waves have to be in phase, not out of phase. The polarity of the wave has to be inversed.

--
This message brought to you by Jack Schitt's Previously Shat Shit
Re:Keep everything quiet by Cosmic_Hippo · 2004-03-15 14:38 · Score: 1

I always wished I could get ahold of a set of the Bose to test out. I've got a set of the Sony MDR-NC20 and I love them. I've heard the Bose are much better, but for the money I can live with mine for now. Too bad I can't wear them at work.
Re:Keep everything quiet by shadowbearer · 2004-03-15 14:54 · Score: 1

I tried out a pair of the Bose headphones once, and they are amazing. A little out of my price range, considering I don't really need them, but on my wish list nonetheless.

Now I need a pair that cancels out the muzak at work but still allows me to hear most everything else. Oh, and they have to be stealth headphones, maybe looking a lot like more modern hearing aids.

/boss "Hearing problems"?

/me "Well...yes. Mostly psychotic, erm, I mean aging, yeah, that's it."

SB

--
It's old. The more humans I meet, the more I like my cats. At least they are honest.
Re:Keep everything quiet by extra+the+woos · 2004-03-15 14:59 · Score: 2, Interesting

Heh mentioning sennheiser in the same sentence as bose is like a sin, the two aren't even remotely comparable... bose is just like re-branded cheap paper speakers with a nice looking package etc heh...

--
replacing it with NEW Folger's Crystals! (lets see if they notice the difference)
Re:Keep everything quiet by wik · 2004-03-15 15:24 · Score: 2, Informative

I have both the MDR-NC20 and the older Bose model. If you get the Bose, make sure you pay the extra money for the newer model, otherwise you're better off with the NC20's. The older model has an annoying dongle that takes two AAA batteries. It also requires the batteries to be operating to play any sound. It also seems to amplify the bass a bit more than I like, but some people might thing that's a good thing.

The newer bose model has a battery up on one of the ear pieces (I believe a single AAA), no dongle, and passes sound without being turned on, iirc. It also has a single cord going to one earpiece, instead of the Y split. Both bose models have quite a bit more padding than the NC20's and are closed earphones.

My biggest problem with the NC20's was that I kept stressing the weird mini-plug thing on the bottom of the cord and it finally broke. Fortunately, I'm handy with a soldering iron. Other than that, I think they are a great pair of headphones.

I believe Bose has a 30-day "test it out" period with their headphones, so you could give them a try.

--
/ \
\ / ASCII ribbon campaign for peace
x
/ \
Re:Keep everything quiet by Reverberant · 2004-03-15 15:30 · Score: 1

Bose noise cancelling headphones suck
I know Bose bashing is always fashionable, but in my experience, the Bose headsets work pretty well. They may or may not be best-in-class, but they most certainly do not "suck."
Re:Keep everything quiet by AnalogDiehard · 2004-03-15 15:57 · Score: 1

Could be a useful mute tool for the girlfriend when she goes on too long:
I'm hearing impaired and I wear a hearing aid.
"Sorry honey, my battery must have gone dead while you were talking."
My solution is easy :)

--
Eternity: will that be smoking, or non-smoking? I Corinthians 6:9-10
Re:Keep everything quiet by Thagg · 2004-03-15 16:22 · Score: 1

I wear my Bose QuietComfort II headphones at least 12 hours a day -- they make my noisy office a quiet contemplative place. Once you wear them for a while, you just can't take them off -- they're that good.

I had the previous model as well, and while they were great at noise cancelling, they had the brains in a separate box with a inconveniently short cable. I rigged up a power-supply to them, so I didn't have to keep changing the batteries.

The new ones have the battery and the brains in the headset. As I don't care to listen to music (just silence) they are self-contained and still pretty light.

I have to say that they are not particularly durable, however. The plastic pieces of both sides of the hoop have broken, and are currently held together with gaffer's tape. You'd think that something that cost $300 would be a little more sturdy.

Still, I love them. If they were stolen I'd buy a new pair tomorrow without thinking about it. Probably the gaffer's tape makes them less attractive to thieves :)

Thad

--
I love Mondays. On a Monday, anything is possible.
Re:Keep everything quiet by makapuf · 2004-03-15 20:51 · Score: 2, Funny

Note that it can be non realtime, too. If you record your neighbours when they make some noise, then, say, one hour later, play it back VERY loud, and you repeat each time they make noise, you'll see some noise cancellation effect quite soon.
Re:Keep everything quiet by Anonymous Coward · 2004-03-15 21:16 · Score: 0

You have no problems if your girlfriend calls you "GOD".
Re:Keep everything quiet by bablefisk · 2004-03-16 00:00 · Score: 1

Unless you are in an environment where close to nothing of the soundwaves get reflected from walls/ceiling etc, you'd have trouble getting this working. The speakers would never be able to cancel out all the different reflections, and would just cause more noise. :)
Re:Keep everything quiet by jsebrech · 2004-03-16 03:10 · Score: 1

The etymotics are in-ear. Most people don't want to wear in-ear for hours upon hours (I get ear infections if I do that).

I sleep with my bose quietcomforts. All night long. I have to. My neighbour loves playing loud techno music late at night (it ironically helps him sleep). Without the headphones I'd have to call the cops before I could get some sleep.

The original quietcomforts were indeed becoming outdated. The competition had caught up to them and improved upon them. Which is why bose released a new generation. Better audio quality, no more background hiss (this never annoyed me, but it did with some people), lighter weight, no more separate audio processing box.

I agree bose makes a lot of crappy products, but the quietcomfort headphones are not among those. As an owner of them I can attest to them being a quality product. And one you can no longer miss when you own it. It's surprising how much annoying noise there is once you get used to being able to shut it out on command.
Re:Keep everything quiet by polyp2000 · 2004-03-16 04:18 · Score: 1

whoah those are expensive..

I bought a nice pair of Sony ones for 60dollars in best-buy while i was in the states this christmas. There was a cheaper pair of "obscure make" ones for 40dollars which I had to take back as they were crap. These Sony ones are beauties though!

--
Electronic Music Made Using Linux http://soundcloud.com/polyp
Re:Keep everything quiet by Anonymous Coward · 2004-03-16 06:43 · Score: 0

Move neighborhood to orbit.
In space, no one can hear you scream...
Re:Keep everything quiet by afidel · 2004-03-16 07:05 · Score: 1

I wasn't aware that they had a new generation of product out. Guess I will have to look into them. If they can keep out airplane noise then I might consider them because as you said wearing the Epy's for extended periods can be annoying.

--
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Re:Keep everything quiet by apdim · 2004-03-16 07:25 · Score: 1

Check out also the Sennheiser PXC250 headphones. They use the same technology used to reduce noise in airplane cockpits and they are very small and ver portable also. Quite amazing effect especially when you use it in an airplane! At last you can sleep i these long trans-atlantic flights.

Why'd it take so long? by tec27 · 2004-03-15 13:42 · Score: 0

I can't see why someone hadn't put this into action sooner. Its basically a white noise generator with a more precise frequency range, and this type of thing has been used in other industries for years.

Take out the fan, problem solved. by Anonymous Coward · 2004-03-15 13:42 · Score: 0, Funny

CPUs don't get as hot as they used to; the bits move much faster through today's processors as a result of lower overhead friction. Lower friction means less heat, less heat means no need for noisy fans. The fan blade and bearing industry would have you believe that your off-the-shelf PC needs several fans to keep cool but this is simply to prop up the illusion that your system is so powerful that it needs to sound like a jet engine (pun NOT intended) to demonstrate the raw power needed to cool such a strong processor.

- eT

Mods... by c0dedude · 2004-03-15 13:42 · Score: 2, Interesting

Mod points to a poster who can point me to a download site for this or something like it, want to try it myself, will put a little speaker by the fan. Or is this not the way it works? Would a computer be too slow to pull something like this off sucessfully?

--
Since when has this country used intellectual elite as a pejorative term?

Re:Mods... by Anonymous Coward · 2004-03-15 13:44 · Score: 1, Funny

Mod poinst? But, um, you just posted....
Re:Mods... by GregChant · 2004-03-15 13:46 · Score: 1

It's a piece of hardware, not software. It replaces (or attaches to?) your normal CPU fan.
Re:Mods... by c0dedude · 2004-03-15 13:47 · Score: 1

Yeah, but to provide incentives I go back and up previous posts of a poster who answers my questions. Call it mod tyranny, but it gets questions answered.

--
Since when has this country used intellectual elite as a pejorative term?
Re:Mods... by WaterTroll · 2004-03-15 14:00 · Score: 2, Informative

how it works it also has more informative links.
Re:Mods... by cr0sh · 2004-03-15 14:18 · Score: 2, Informative

Something like this should be fairly easy to construct - whether it would work well or not, that is another thing.
First, get yourself a copy of Forrest M. Mims III's "Engineer's Mini-Notebook - Op Amp IC Circuits" (RS 276-5011) - probably not very easy to find (I believe it may be out of print - go to ratshack and ask). Alternatively, grab a copy of "The Forrest Mims Engineer's Notebook" (ISBN 1-878707-03-5).
Ok, now - if you have the mini-notebook, look on page 12 - if you have the other book, look on page 93. Basically, what you are looking for is the "Inverting Amplifier" (both circuits are nearly identical - though the original booklet shows a resistor R3 hanging off pin 3 of the 741).
So, anyhow, you run your mic input (exercise left for the reader) into the Vin to pin 2 of the 741, and an inverted waveform will show on pin 6. Run that output through an amplifier, then the output of the amp into a speaker - and there is your basic sound cancellation system.
By taking the input sound waveform, inverting it through the 741, amplifying it, then outputing it through a speaker - the valleys and crests of the two waveforms should nearly match each other (with the exception of a slight delay introduced by the circuit/amps).
Want to take it a step further? Tie an A/D and a D/A on each end - and inbetween set up a really fast DSP or microcontroller, and perform on each sample of the waveform a form of amplitude forecasting - so that you can maybe cancel out the effects of the delay in the circuit by adjusting for them dynamically. Probably would be difficult to do homebrew, but if you grok what I am talking about, you can see how it would help, and why it would be fun to try.
Hope this inspires someone - good luck!!!

--
Reason is the Path to God - Anon
Re:Mods... by eliphas_levy · 2004-03-15 14:25 · Score: 1

Look at this project.

Build your own noise-cancelling headphone and save your bucks.

Don't know if the circuitry would be the same for the fan, tough.

--
eliphas
Re:Mods... by Sycraft-fu · 2004-03-15 14:26 · Score: 1

Oh your computer can easily do it, it's a matter of having the right software and successfully calibrating it. The tirck is that not only must the speaker produce the inverse sound wave, it needs to do it at the right time so it collides with the orignal wave and cancels. I mean if you want to try it simply, just get a mic and speaker, and invert the positive and negative somewhere. That'll get you an inverse wave. Probably won't get it to do a good job canceling, though you can try fiddling with the positioning to try and make it work better.
Re:Mods... by drinkypoo · 2004-03-15 14:44 · Score: 1

Nah the computer can do it just fine, in fact if your voltages are pretty steady it shouldn't even take too much CPU time. It's a job best handled by a DSP but that's what MMX and 3DNow and such are for, DSP-like functionality in your general purpose CPU. Basically you have to have to be able to hear what you've accomplished, and then your system can be self-tuning, or have very very tight control over the environment (such as the inside of a pair of headphones) and have sensors to pick up incoming noise, whose characteristics you know very well.
It is not out of line to expect the computer of the future (DUN DUN DUN) to be able to listen to itself (even the i-Opener has a microphone, but it's so close to silent already as makes no difference to most people, I can only barely hear the backlight) and adjust its fan speeds, then apply antinoise sound processing to mute the remainder of its noises. The only thing I can see wrong with this is that done poorly it will set you on edge all night if you're sensitive to that sort of thing, so this is still no substitute for a system so efficient it needs only passive cooling in most environments.

--
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Re:Mods... by 216pi · 2004-03-15 21:10 · Score: 1

You can't mod in a story you posted before...

now, I'll go and mod you down. oh wait... damn.
Re:Mods... by Mindcry · 2004-03-16 06:30 · Score: 1

easiest way: find a home stereo with an aux input, plug in a mic, plug the red speaker wires into the black ports, and the black wires into the red ones...

simple inversion ;) no need to build your own amp.
Re:Mods... by John_Schmidt · 2004-03-16 15:18 · Score: 1

Even easier - take the red wire and twist it with the black one - instantly (other then the initial 'woof') - no noise.

Yes, avoid performance cost of muffler! by enosys · 2004-03-15 13:42 · Score: 1

I've seen this idea someplace quite a while ago. They were talking about using noise cancellation instead of mufflers. That way you'd reduce noise without any of the flow restriction from a muffler.

Re:Yes, avoid performance cost of muffler! by Woody77 · 2004-03-15 17:00 · Score: 1

You actually want mufflers on cars. The resonance of having mufflers actually helps the engines to run. It's been empirically proven in some circles that removing the muffler (and catalytic converter) degrade the performance of the engine.

two things.. by glenkim · 2004-03-15 13:43 · Score: 1

first of all, where are the sound clips?

second of all, this would be interesting to mix with a car exhaust, if you can find components that wouldn't die in the heat. imagine straight-pipe exhausts that are quieter than today's systems with mufflers!

Re:two things.. by laugau · 2004-03-15 14:26 · Score: 1

A potato is a good sound cancelling device for your car. Just stick a potato in your exhaust pipe and your car will not make any more noise.

Of course, it takes a short time for the sound waves calibrate... you have to let the car run for a few seconds before the potato builds up a good harmonic. Just be patient until you get the desired result.
Re:two things.. by xs650 · 2004-03-15 14:31 · Score: 1

If it really worked there could be no sound clip. Which reminds me.... Shortly after the F-117 stealth fighter became public knowledge, a Brit reporter at an Airshow asked the USAF Major PR officer at the air show why the Stealth Fighter wasn't at the air show. The Major replied "How do you know it isn't."

Alternatives to Noice Cancellation by breakinbearx · 2004-03-15 13:43 · Score: 4, Informative

Although, it would be very very cool to get this technology to work on big loud things, and is very cost effective, for quite pc's, the Voodoo F:50 does a very good job at keeping noise at a minimum, using no fans, only convective heat pipes, and using the entire case as a heatsink. Voodoo claims that their system operates at below 20 dBs, and cannot be measured in a room with regular ambient noise.

--
Skill is successfully walking a tightrope over Niagara Falls. Intelligence is not trying. -- Anonymous

Re:Alternatives to Noice Cancellation by irokitt · 2004-03-15 13:45 · Score: 1

I have salivated over a Voodoo system for ages. Ditto for the equally soundproofed and outrageous Falcon Northwest systems. But you can't get around the fact that they are very expensive. Well beyond my means at least. So my computer sounds like a 747 taking off.

--
If my answers frighten you, stop asking scary questions.
Re:Alternatives to Noice Cancellation by Tin+Foil+Hat · 2004-03-15 14:41 · Score: 1

That's a pretty slick PC, but for 3,500 bucks, I think I'll just use a decent fan cooler. There are plenty on the market that deliver good cooling at low noise and energy levels. Combine that with a few similar fans for the case, and almost any PC can run at barely perceptible noise levels for a very modest cost.

On the other hand, if I ever win the lottery, I'll be first in line over at Voodoo.

--
No matter how many of my rights are taken away, somehow I still don't feel safe. -Frigid Monkey

It never ends though by irokitt · 2004-03-15 13:43 · Score: 5, Funny

Once you silence my CPU, you'll hear my hard drive. After you silence my hard drive, contend with my video card cooler. Quiet my video card cooler, and hear all 4 of my case fans instead. Quiet those, and hear the active cooler on my northbridge. Shut that up, and I'll go mad with all the silence...

--
If my answers frighten you, stop asking scary questions.

Re:It never ends though by dlevitan · 2004-03-15 14:11 · Score: 3, Funny

No, that's not how it ends. I actually did this. I bought a very quiet hard drive (Seagate Barracuda IV), and a quiet power supply (Antec Trupower 330). But then the video card fan made too much noise, so I bought a replacement. But then the power supply was two loud, so out went the standard "loud" fan and in went a super-quiet pc power & cooling fan. Then the CPU fan and the case fans became too loud, so I replaced them all with the same fans as the power supply. But then the PS fan was still too loud, so I put in rubber spacers and undervolted the thing. But then the case fans were too loud and I undervolted them. But then the PS fan was too loud, and I undervolted it. Except that then my PS started overheating from the heat rising from my CPU. So I built a duct from the CPU directly to the outside of the case (which works fairly well). It's still too loud, and I don't really know what else to do except possibly undervolting the fan on my cpu. But if I start with that again, I'll probably never stop.
Re:It never ends though by shadowbearer · 2004-03-15 15:00 · Score: 3, Interesting

Damn funny post, irokitt.

One day a fan on your computer fails, and you never noticed, because you couldn't hear the squealing of the tortured bearings...

The interesting thing is with modern mobos (which control fan speed based on how hard the cpu is working/generating heat) you can actually tell to a point what's going on. I can set a compile going, go sit on the couch and read a book, and tell when it finishes (the cpu fan noise goes down and the hard drive noise goes up briefly - I run Gentoo where it writes the files at the end of the compile/emerge).

SB

--
It's old. The more humans I meet, the more I like my cats. At least they are honest.
Re:It never ends though by Patik · 2004-03-15 16:23 · Score: 2, Funny

I run Gentoo where it writes the files at the end of the compile/emerge.
You complied something in Gentoo and it finished!?
Re:It never ends though by irokitt · 2004-03-15 19:08 · Score: 1

I run Gentoo on an older machine, and I noticed the same thing. But I'm usually asleep when it finishes compiling something.

--
If my answers frighten you, stop asking scary questions.
Re:It never ends though by The+Famous+Brett+Wat · 2004-03-15 20:03 · Score: 2, Interesting

I have (and am posting this using) a VIA EPIA-M motherboard with passive heatsinking, no hard drive, an external fanless power supply, and no case fans. (It acts as an X terminal for another system.) There are no moving parts in the system at all. Believe it or not, however, I can hear a small electrically-generated squelching sound when there is ethernet activity (when all else is quiet in the dead of night). I could try WiFi, I suppose.

--
proof, n. A demonstration that a conclusion is implied by certain premises and axioms.
Re:It never ends though by TwistedGreen · 2004-03-16 01:16 · Score: 1

Where does one get an external fanless power supply? Did you adapt it from another system or can you buy them individually?

This would be a very welcome idea in computer design, I think. I know Apple's done this before, but it would work wonders in helping quiet my PCs.
Re:It never ends though by The+Famous+Brett+Wat · 2004-03-16 03:12 · Score: 1

The external fanless power supply I am using is just a brick that provides 12VDC at 4+A -- the kind of power supply you might find on a laptop. Inside the computer case is a DC-DC converter, which is then attached to the standard ATX power connector on the motherboard.

--
proof, n. A demonstration that a conclusion is implied by certain premises and axioms.
Re:It never ends though by NeMon'ess · 2004-03-16 04:00 · Score: 1

i know you're being funny, but you should know those pc power & cooling fans are only 20db and not audible from more than 2 feet away. so if you've got your computer on your desk next to your monitor that's part of your problem. keep the box on the floor a few feet away.

I could use this by crass751 · 2004-03-15 13:45 · Score: 3, Interesting

My laptop is so loud that if the fan(s) isn't/aren't running my roommate asks me if I turned it off. This thing generally has two fans running at times, and when it's really working hard, a third kicks in. My four year old desktop machine is much quieter than this thing.

Stupid HP. Had to go sticking a desktop chip in a laptop. Oh well, it still runs circles around my roommate's silent Centrino-based machine.

Re:I could use this by wscott · 2004-03-15 14:28 · Score: 1

Yes, and I would take your roommate's computer every time.
Re:I could use this by LordSah · 2004-03-15 14:44 · Score: 1

Did you know that it was a desktop chip before you bought the laptop? Seems that you'd have to know a little about what you were jumping in to...
Re:I could use this by crass751 · 2004-03-15 14:56 · Score: 1

I got it as a gift. I knew it had a desktop chip, but had no idea it would be as loud as it was. Hindsight is 20/20. Oh well.
Re:I could use this by LordSah · 2004-03-17 07:44 · Score: 1

Not much you could've done about it then :)

Finally... by Seoulstriker · 2004-03-15 13:45 · Score: 2, Funny

Finally I can run that 120mm x 38mm Tornado fan at full speed without going deaf! I wonder if the same device could be used to silence my computer's other 10 fans.

--
I am defenseless. Use your button. Mod me down with all of your hatred.

Maybe not for fans by Daikiki · 2004-03-15 13:46 · Score: 2, Funny

This noise reduction technology only cuts out whining, you say? Can I order one medium sized one for my wife, 3 smalls for the kids and an extra large for my mother-in-law? I'll pay extra for overnight delivery!

--
I want the fire back.

Absorbing technique instead by fembots · 2004-03-15 13:47 · Score: 5, Interesting

In most offices, they don't use noise generators (ie Gossip Support Group) to cancel out talking noises, instead they put in a lot of plants, cubicles, which act to absorb most of the noises.

If the noise is pointing at your directly, then you probably need a cancelling method. If it is a general-direction noise, it should be absorbed rather than trying to cancel it (where you need to find it in the first place).

--
Rock that crushes, Paper & Scissors that don't matter.

Re:Absorbing technique instead by Reverberant · 2004-03-15 14:08 · Score: 1

You're talking about masking, which is the practice of "covering" softer sounds with louder sounds. It's one of the acoustic principles that are exploited for perceptual audio codecs.
Re:Absorbing technique instead by flappinbooger · 2004-03-15 14:23 · Score: 1

A certain level of ambient noise is needed for privacy, along with the plants, acoustical tile ceilings, etc.

I was speaking with a guy who works for an A/C industry company who gets all scientific with delivering cool air and stuff, and a big problem with buildings is being TOO quiet.

There's a certain dB level of white noise that's needed in a space, otherwise you hear everything around you in the cube farm. The ambient noise makes it so you don't really notice when the guy next to you is on the phone.

--
Flappinbooger isn't my real name
Re:Absorbing technique instead by drinkypoo · 2004-03-15 14:50 · Score: 1

The problem with using absorption as your primary method is that the whole building has to be designed around it, in terms of shape and materials. Otherwise a room tends to have spots which are more reflective than others. Many buildings I have been in have had a very strange feeling to them at least in part due to the acoustics, likewise certain times when I have been underground, and I feel very strange when walking next to the wall in a movie theater without that aural sense providing useful information on one side of my head. (Oddly enough being in a little tunnel underground in the utter darkness is better than that feeling, and I usually have issues with close spaces. But at least you can hear what's going on around you.) Right now I'm sitting in front of a large open vent which is the house swamp cooler, a downdraft model which we have fitted with a vent. It's blowing across some sheet steel and right over (but not through, at least not straight through) my monitor. It feels really damned weird. So suffice to say, this shit is more complicated than just plopping a bunch of partitions and plastic plants around the office, though such things can help. Filling it with a bunch of meaty sacks of water can only help as well, without even getting into the plethora of ambient noise they will generate to mask whatever it was you were trying not to hear - unless it's them, anyway.

--
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Re:Absorbing technique instead by reidbold · 2004-03-15 14:59 · Score: 4, Funny

Yeah man, damn plants and cubicles never shut the hell up.

--
-Reid
Re:Absorbing technique instead by utlemming · 2004-03-15 15:34 · Score: 2, Informative

I noticed that my University employs the use of masking. While taking a test in the religion department at my University, I noticed that the air conditioner was a little loud. Looking around, I noticed that there were four speakers placed near the doors of the religion professors. I figured this was to provide privacy for the professors when counseling people, and so passer-bys would not hear any of the comments. Anyhow, since then, I noticed that in the new building that was just completed, there are a lot of these air-condition sounding speakers. It is a lot cheaper to implement a system where you just have a speaker replaying the sound of an air conditioner, than by going out and getting a system that creates white-noise.

--
The views expressed are mine own and do not express the views of my employer.
Re:Absorbing technique instead by Anonymous Coward · 2004-03-15 16:29 · Score: 0

some one shut the person in this cubicle up.
corporate accounts payable, meena speaking... justa moment
corporate accounts payable, meena speaking... just a moment

-----
Hey Peter... whaaats happening

Comment removed by account_deleted · 2004-03-15 13:48 · Score: 3, Funny

Comment removed based on user account deletion

Sign me up for the beta! by Anonymous Coward · 2004-03-15 13:50 · Score: 0

I want one. No two. No, 20. Imagine a Beowulf cluster running with these. Are your servers on? Yup.

Those danged mormons... by Anonymous Coward · 2004-03-15 13:51 · Score: 0

First they make electricity in fruit jars, now they done figured out how to make sound waves disappear. What will they think of next. Been thinking about joining their church just so they would let me attend BYU..... Dang..

Re:Those danged mormons... by LBArrettAnderson · 2004-03-15 15:23 · Score: 1

1.) the cold fusion people were from utah state (or another public university, not byu) 2.) you don't have to be mormon to go to byu. 3.) this isn't the first time someone has made sound waves disappear. i know that's probably redundant, but just in case you're 12 or something.

Wind tunnels... by SmackCrackandPot · 2004-03-15 13:51 · Score: 2, Funny

We have a industrial PC that sits in a wind-tunnel. To us that's the largest cooling fan anyone would ever want.

two things inRe:#2 thing.. by mynameis+(mother+... · 2004-03-15 13:52 · Score: 1

second of all, this would be interesting to mix with a car exhaust, if you can find components that wouldn't die in the heat. imagine straight-pipe exhausts that are quieter than today's systems with mufflers!

First, someone was doing this years back. Can't for the life of me say who, but I saw it on TV, so ;) Seriously, someone had a prototype sonic interference type muffler system.

Secondly, someone posted about this above, adding the fun idea of additionally altering the emotional qualities of your exhaust...

Your solutions are crap by Chuck+Chunder · 2004-03-15 13:52 · Score: 3, Insightful

Quiet fans tend to get noiser with age.

A box is not going to be good for heat dissipation or size constraints.

Water cooling is certainly not going to be cheaper or less complex.

If an active sound nullifier that will automatically adapt to the changing noisyness of a fan as it ages can be made for as little as $20 it is surely a more credible solution than your suggestions...

--
Boffoonery - downloadable Comedy Benefit for Bletchley Park

Re:Your solutions are crap by Zakabog · 2004-03-15 14:26 · Score: 2, Insightful

The fan will change noises as it gets older and somehow the microphone and speaker will remain perfect forever? If either the microphone or the speakers are damaged they'll end up creating more noise then they cancel out. What happens if the microphone starts picking up feed back then your computer's creating more noise than it started off with?
Re:Your solutions are crap by Anonymous Coward · 2004-03-15 14:49 · Score: 0

The fan will change noises as it gets older and somehow the microphone and speaker will remain perfect forever? If either the microphone or the speakers are damaged they'll end up creating more noise then they cancel out.

Are you being sarcastic? That is absurd. A microphone or speaker exposed to such a little amount of use (with barely any change in input/output) would last a hundred years. Of course it'll fuck up if they become damaged in some other way, but every other soltion you presented has that same caveat. (with added dangers, in the case of water cooling components becoming damaged)

What happens if the microphone starts picking up feed back then your computer's creating more noise than it started off with?

If the system were designed by a complete moron, then this might happen. The obvious solution here is to design it properly in the first place.
Re:Your solutions are crap by Anonymous Coward · 2004-03-15 15:07 · Score: 0

Ummm you're ignoring the box and closet ideas. I know of desks that were built with doors in front of where the computer goes, with the door closed you can't hear the computer at all. These people didn't buy the desks for that reason either they just liked the desk and it just happened to cancel out the noise. There are so many other ways that won't fail trying to reduce the noise, a desk isn't $20 but if you need a desk anyway why not buy one that can keep your PC quiet?
Re:Your solutions are crap by Chuck+Chunder · 2004-03-15 15:15 · Score: 1

The fan will change noises as it gets older and somehow the microphone and speaker will remain perfect forever
Compared to something spinning round at several thousand rpm for it's entire working life, most certainly.

--
Boffoonery - downloadable Comedy Benefit for Bletchley Park
Re:Your solutions are crap by Anonymous Coward · 2004-03-15 16:17 · Score: 0

There are so many other ways that won't fail trying to reduce the noise, a desk isn't $20 but if you need a desk anyway why not buy one that can keep your PC quiet?

Most people already have desks, many people (myself included) don't like having drawers/cupboards included in their desks. The cupboard/desk idea doesn't take heat issues into account (unless they are ventilated spaces, which is more expensive and comes with its own fan-noise problems).

Personally, I like having my PC on/under my desk where I can get at it easily. A $20 component like this would make my workspace a lot more pleasant, but just as functional.
Re:Your solutions are crap by RzUpAnmsCwrds · 2004-03-15 18:05 · Score: 1

"Quiet fans tend to get noiser with age."

My Panaflos are still running quiet after two and a half years. If they do get noisy, I can replace them - for about $8 each.

"If an active sound nullifier that will automatically adapt to the changing noisyness of a fan as it ages can be made for as little as $20 it is surely a more credible solution than your suggestions..."

The active sound nullifier cannot remove all airflow noises. The real solution is better designed airflow systems (like in most commercial PCs - note how quiet most recent HP or Dell systems are), thermally managed fans, and cooler CPUs.
Re:Your solutions are crap by ZigMonty · 2004-03-15 18:16 · Score: 1

What happens if the microphone starts picking up feed back then your computer's creating more noise than it started off with?
Think about it. The speaker will always be emitting the opposite of the sound it receives. How can that feed back? Sure, it may cancel less effectively with time, but I doubt it could make things worse.
Re:Your solutions are crap by Anonymous Coward · 2004-03-16 01:17 · Score: 0

I have 12dB Japanese CPU fan (from http://www.sne-web.co.jp/) cooling my number crunching box. It has survided two-month computations and outlived one HD and one power supply. And I haven't noticed (=heard) any aging effect in it. Anybody in need of Coolermaster "Silent Draco" 26dB DP5-6131C-J1 can pick it up for free from me (http://www.iki.fi/petterik/mail.php). Original Intel CPU on the sale (dBs unknown).
Re:Your solutions are crap by Kiryat+Malachi · 2004-03-16 02:37 · Score: 1

Its called negative feedback, and there are quite a few ways where a negative feedback system can go into oscillation and start emitting sound.

Its possible. On the other hand, it remains unlikely.

However, having done something very similar, I'm skeptical about this. Generally you can only cancel for one point in space, which works fine for headphones, but isn't so useful for someone who moves around their cubicle or office all day.

--

---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)

psht. by MC_Cancer_Pants · 2004-03-15 13:54 · Score: 1

I want one of these for some of my anatomy lectures. What? leukocytosis? *flip* can't hear you, sorry. *flip*

Re:psht. by glenalec · 2004-03-15 20:20 · Score: 1

I want this in my classes too.

(I'm the teacher.)

--
The man with no surname and a silly hat

On the universe: It's bunk.

Not universal by irokitt · 2004-03-15 13:54 · Score: 1

Unfortunately, there would have to be a different frequency of noise cancellation for every different CPU fan out there. Most people run "stock" CPU fans, but even the stock fan approach gets negated because there are several different models that have been distributed over time. So it isn't just a simple download.

--
If my answers frighten you, stop asking scary questions.

Re:Not universal by mog007 · 2004-03-15 15:28 · Score: 1

I'm sure there's software out there that would allow you to input your particular fan's noise via a microphone, then the software could phase shift it to create the negation effect, then produce that sound out a speaker. I'm no sound engineer or audiologist, but it shouldn't be too difficult.

--
Learn something new.

Prior art? 'rev' by janbjurstrom · 2004-03-15 13:55 · Score: 3, Funny

$ echo 'I CANT HEAR YOU' | rev
UOY RAEH TNAC I

Ah, the silence :)

--
668.5

Re:Prior art? 'rev' by MichaelGCD · 2004-03-15 16:17 · Score: 1

In soviet russia, you can't hear I!

--
hate titty pee colon slash slash
Re:Prior art? 'rev' by Anonymous Coward · 2004-03-15 18:45 · Score: 0

Psh. Not the Gay Nigger's Association of America?

Re:No need to worry. by Anonymous Coward · 2004-03-15 13:56 · Score: 1, Interesting

It gets harder and harder the higher in frequency you go because of the decrease in wavelength. Seagate drives are pretty quiet. Also, use 5400RPM drives for data storage, 7200 to run your system. 5400 drives are cooler and fail less often.

Wrong direction by Anonymous Coward · 2004-03-15 13:57 · Score: 5, Insightful

All this does is allow PC makers to get away with making hotter and noisier systems. We should be pressuring the industry to be cooler and more efficient.

Re:Wrong direction by reidbold · 2004-03-15 14:55 · Score: 2

Nah, I want faster. The money I spend on powering my computer is well spent, and would gladly spend more for more computing power.

If you want cooler and quieter, get a laptop I guess.

--
-Reid
Re:Wrong direction by Hans+Lehmann · 2004-03-15 15:48 · Score: 1

Do you only buy computers that have no fans in them whatsoever? After all, adding fans just encourages manufacturers to make hotter and noisier systems. And let's not forget about heat sinks. Any manufacturer that needs to use heat sinks is just being lazy.

--
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

What incorrect unit is 150W/sec ? by Anonymous Coward · 2004-03-15 13:57 · Score: 0

1W = 1J/sec

So 150 W/sec = 1 J/sec^2

What the heck is that ? Some kind of acceleration ?

Wow, imagine... by serutan · 2004-03-15 14:00 · Score: 4, Funny

A Beowulf cluster of those, attached to Rush Limbaugh.

Re:Wow, imagine... by shadowbearer · 2004-03-15 15:03 · Score: 1

Preferably permanently.

SB

--
It's old. The more humans I meet, the more I like my cats. At least they are honest.
Re:Wow, imagine... by Anonymous Coward · 2004-03-15 15:41 · Score: 0

I don't post as an AC
awwww whats the fun in that? its like having your cake and eating it too. you can act like a goofball and go on a huge rant for no other reason that someone cut you off in traffic today.
Re:Wow, imagine... by Felinoid · 2004-03-15 20:50 · Score: 1

I'll get back to the "random slam" in a moment. First let me explain why this dosen't work.

Noise cancling won't work on the human voice or any irregulare noise (like your brother blasting music).
It repeates an inverse wave of noise to cancle it. The inverse wave has to be a match to the current noise. This means the person has to be repeating himself over and over in a predictable patern to work.
This may work for lay politicians but any talk show host he is predictable enough to be noise cancled would be cancled by the network and replaced.

Now as for the obigitory Limbaugh slam.

Most people who slame the Macintosh don't know anything about the Mac and just repeate what they heard.
Most people who slam Linux do so based on other peoples clames.
This also happends to be true of Mr Limbaugh.

You'll find every person who slames Limbaugh dose so as a lame attempt to slam the republican party.
Mr Limbaugh dosen't run for office he just states his opinion and the people who lissen do so becouse they agree with him.

In this day and age if you can not rip appart clames by the Republican leadership and need to rely instead on vage attacks on conservitive talk show hoasts you really need to give up.

I mean come on people. Even I know Bush screwed up on WoMD. Who cares about some talk show host when you've got gems like that?

--
I don't actually exist.
Re:Wow, imagine... by Anonymous Coward · 2004-03-16 02:22 · Score: 0

Should be Darl.
Re:Wow, imagine... by cardshark2001 · 2004-03-16 05:24 · Score: 1

I have a feeling most Limbaugh defenders spell just as atrociously as you do. Let's see:
dosen't, cancling, irregulare, repeates, cancle, patern, cancled, cancled, obigitory, clames, slame, repeate, happends, slames, dose, lissen, becouse, appart, clames, vage, conservitive, hoasts
I'm not even going to start on your grammar. How can you expect for people to take your opinions on an intellectual topic seriously unless you learn to spell, or at the very least learn to use a spell checker?

--
WWJD? JWRTFA!

Analog Devices app note for this four years ago by dlleigh · 2004-03-15 14:01 · Score: 4, Informative

Analog Devices published an app note for this exact application four years ago.

"Adaptively Cancelling Server Fan Noise" can be found here. They were able to lower the whine by 30dB and the broadband noise by 20dB.

Re:Analog Devices app note for this four years ago by Anonymous Coward · 2004-03-15 17:56 · Score: 0

They were able to lower the whine by 30dB and the broadband noise by 20dB.

I need that, the noise on my phone line kills my download speed, I only get about 0.8Mbps down even though I signed up for the 1.5 package.

24 volt fans by cyber_rigger · 2004-03-15 14:02 · Score: 2, Insightful

If you don't need a massive airflow try a 24 volt fan. They still provide air circulation and are very quiet running on 12 volts.

Re:24 volt fans by Anonymous Coward · 2004-03-15 14:14 · Score: 0

.. or put a voltage divider on the 12v line, to power it with 6v. That's what I do.
Re:24 volt fans by Frogbert · 2004-03-15 14:53 · Score: 1

Or connect both the +5v and the +12v line to the fan which gives you a smooth +7v.
Re:24 volt fans by neurojab · 2004-03-16 03:36 · Score: 1

Or you can buy a cheap varaible resistor (such as those made by Zallman) and use your existing fan.

Power Supply by jmichaelg · 2004-03-15 14:05 · Score: 3, Insightful

I installed an 80 mm Panaflow on top of a $30 all-copper heatsink to cut the noise from my computer but it didn't do much. As soon as the cpu fan noise was gone, the power supply noise was that much more noticeable. I ended up installing a new power supply. It was the best $80 I ever spent. The combination of a quiet cpu fan and quiet power supply result in a reasonably quiet computer. Not dead silent but at least it's no longer objectionable.

Re:Power Supply by StArSkY · 2004-03-15 14:53 · Score: 1

You have absolutely nailed it with this answer.

A good copper heatsink (eg Thermalrigh SLK800U) and a cool silent Panaflo L1A 80mm fan is almost completely silent.

I started with a good case, then the heatsink fan just like you, and then I had to replace my motherboard for one with less voltage toredude the heat a bot, to slow the fan down more... then the PSU ... and then my Northbridge Fan with a big heatsink.... and then my video card

Antec Sonata :My Experience

SLK800U & Panaflo : My Experience

Silenx 400w PSU : My Experience

Abit NF7-S v2.0 + Northbridge Heatsink : My Experience

Iceq Radeon 9800 Pro (No experience documented yet)

--
lounge around on the blue couch
Re:Power Supply by Mjlner · 2004-03-15 21:00 · Score: 1

When reading this article I started to get annoyed at the sound of my PC. Darn it, I thought, wasted 150 euro on a silent case+power and another 35 euro on a silent CPU cooling solution and now the graphics card is driving me NUTS! PLEASE make it STOP! AAARGGH!
Then I went to the shower and when I came back the PC was dead quiet... Why? My girlfriend had put the radio on...
...but my GOD how that music is terrible. I can't STAND it! Make it GO AWAY!!!

--
Lemon curry???

diy? by frankmu · 2004-03-15 14:07 · Score: 3, Interesting

can you take apart the cheap "noise cancelling" headsets and do it yourself? i would imagine all the parts and circuitry are there. lets see if my wife will miss her airplane headset....

--
Supreme executive power derives from a mandate from the masses, not from some farcical aquatic ceremony.

Re:diy? by Bagels · 2004-03-15 14:28 · Score: 1

He said he could do it for $20... the cheapest headphones that I saw when I ran a search on Froogle were about $26, and the *good* ones (Bose QuietComfort) were $300. DIY if you want, but it's probably even cheaper to do it with off-the-shelf parts rather than with headphones.

--
--- Bwah?
Re:diy? by PoisonousPhat · 2004-03-15 16:55 · Score: 1

Bose... good... really? Take a look at this, 'The Bose FAQ', then decide for yourself... but don't just repeat the hype. From personal experience, I prefer the Sennheiser line of noise-cancellation headphones for their sound quality, not to mention the far more attractive price point. Most expensive does not always indicate highest quality.
Sorry, I get worked up when people equate "Bose" with "good"... maybe you had good experiences with Bose equipment.

--
Losers choose to abuse the use of "loose".
Re:diy? by Anonymous Coward · 2004-03-16 02:41 · Score: 0

no need to take them appart and start messing with your pc. I find it a lot easier to just put mine over my ears...

I must be retarded by macemoneta · 2004-03-15 14:07 · Score: 3, Funny

I probably should have built a noise canceling tower or some similar nonsense, so I could get published.

Instead of all the research and electronics, I put a drop of oil on the axle and removed the dust from the blades with a q-tip. It's been silent ever since.

Silly me.

--

Can You Say Linux? I Knew That You Could.

Re:I must be retarded by boltfromtheblue · 2004-03-17 03:44 · Score: 1

May be the parent shd be modded insightful.I have done the same and had a HUGE difference in the noise. This should be tried before all the other fancy things.

Specific noise cancellation.. bad. by Anubis333 · 2004-03-15 14:07 · Score: 1, Interesting

I would much rather purchase something that can cancel out noise from any source than from just a cpu. It would be a lot better to mount something between me and my computer. After all the CPU isnt the only noisy thing, I have noisy case fans, noisy 10K HDs, and noisy RAID array's. Not to mention, the "anti-noise gun's" on the market are mobile, meaning at any given time I can turn it to face my girlfriend.

Or, instead by lingqi · 2004-03-15 14:10 · Score: 4, Insightful

Design quieter cooling technologies.

I mean it's not like it's not possible.

Case in point #1: NEC (in japan) has a water cooled computer now on sale to the teeming millions. water runs over the CPU and goes into a radiator to the back of the case. the radiator sits just outside of the power supply fan, which turns at an incredibly low speed (kinda like the apple G5 fans). Damn quiet.

Case in point #2: Mitsubishi, after not building any planes since WWII (zero fighter was by them, after all), entered the business-jet arena. The first thing they did was to design a new shape of turbine intake blades using computer simulation that cuts something like 10dB off the engine noise compared to traditioal strait blade intakes.

So, instead of brute forcing one's way around the noise problem, there are more elegant ways!

--

My life in the land of the rising sun.

Re:Or, instead by Monkelectric · 2004-03-15 14:29 · Score: 1

Case in point #1: NEC (in japan) has a water cooled computer now on sale to the teeming millions. water runs over the CPU and goes into a radiator to the back of the case. the radiator sits just outside of the power supply fan, which turns at an incredibly low speed (kinda like the apple G5 fans). Damn quiet.
Um, I've had a watercooled PC for 3 years, and let me tell you something: its a terrible idea. Mine failed twice, once dumping coolant into the (running) computer. It kept the computer very cool, and the case was very quiet, but computers and water are simply not meant to be.

--
Religion is a gateway psychosis. -- Dave Foley
Re:Or, instead by Anonymous Coward · 2004-03-15 15:01 · Score: 0

Um, I've had a watercooled PC for 3 years, and let me tell you something: its a terrible idea. Mine failed twice, once dumping coolant into the (running) computer.

The NEC product is obviously commercial-grade, which I imagine wouldn't suffer the same issues as your shoddy homebrew setup. (and if anything like that did occur, they'd be bound by warranty to fix it)
Re:Or, instead by rpj1288 · 2004-03-15 16:20 · Score: 1

I happened to see an article in PCGamer about the Voodoo Rage F-50. The whole friggin case is a heatsink. Not a single fan. Make customizing hard, but hey, its silent.

--
Marvin knew: "Think of a number, any number..."

Whinny noise? by 6Yankee · 2004-03-15 14:11 · Score: 4, Funny

Sommerfeldt set about to find a way to drown out the whinny noise from built-in fans that cool computers and other electronic devices.

Did he try a fan with less horsepower?

Cheese by Anonymous Coward · 2004-03-15 14:12 · Score: 0

I just stick cheese in my ears.

What? What?

Edit by Anonymous Coward · 2004-03-15 14:13 · Score: 0

We need proof editors. I somehow doubt the professor starting working on this after realizing how noisy your machine was.

I've got more sounds... by lpangelrob2 · 2004-03-15 14:14 · Score: 5, Funny

it only nixes the whine, not the whoosh

That's good and all, but what about my "braaagh"? I've also got a "whizzz!" and a "fhwhhhh" that still need to be dealt with...

--
-Rob
Marriage doesn't have to suck!

Re:I've got more sounds... by The+Munger · 2004-03-15 14:57 · Score: 2, Funny

A "braaagh" eh? Sounds like you need to stop touching the blades as they spin around. And for the "fhwhhhh", I can recommend realigning the PC into a different magnetic field. Try turning it 30 degrees clockwise.

Or maybe just give it a good hard whack.

--
Refuse to make a statement in your sig!
Re:I've got more sounds... by Anonymous Coward · 2004-03-15 16:40 · Score: 0

I tried that and some blue smoke started coming out the back of my case. And then my screen went blank. And then I saw Elvis!
Re:I've got more sounds... by Anonymous Coward · 2004-03-15 19:26 · Score: 0

That's nothing! Same thing happend to me... but Elvis taught me how to stuff the blue smoke back in the chips!

just get a cpu that doesn't need a fan by Anonymous Coward · 2004-03-15 14:15 · Score: 0

like via's eden chip. it even uses a lot less power too. and if you get a case with an external power supply brick, you don't need any fan at all! ahhhh....

Not a good use of energy by vandan · 2004-03-15 14:16 · Score: 2, Insightful

Cancelling sound with sound sounds cool, but it's a waste of energy. Surely there are cheaper, more environmentally friendly ways of protecting our sensitive ears from the nasty CPU fan noise.

Every little bit counts. Just imagine if we didn't have to invade Iraq for their oil because we could properly manage our energy usage and R&D into renewable energy sources.

Re:Not a good use of energy by Vellmont · 2004-03-15 15:01 · Score: 2, Insightful

Whaa? Less than a watt of energy used to power speakers is a "waste of energy"? Your post is a waste of energy. Every little bit does NOT count. I'm really sick and tired of this nonsense of adding up miniscule "savings" and making them into big sounding numbers to the ignorant masses.

There's this attitude that's developed among the eco-freaks in this country that they can save the world by reducing their own personal consumption by .01%, because "every little bit counts. Not flushing your toilet to "save water" is idiotic. If you want to "save water" don't water your lawn, or stop lettings farmers irrigate farm land. Worrying about a watt of energy to do noise cancellation is equally idiotic. If you want to use less oil stop driving the goddamn gas guzzling SUVs.

--
AccountKiller
Re:Not a good use of energy by reidbold · 2004-03-15 15:02 · Score: 1

Or just use fission, a fairly well proven which happens to be pretty clean. If only everyone didn't run around like chicken little when the topic comes up.

--
-Reid
Re:Not a good use of energy by AVGVSTVS · 2004-03-15 15:14 · Score: 2, Insightful

I think you miss the point, its not about saving the world, its about totalitarianism. "It is a waste of energy" is not an objective, rational, scienfitic statement of efficiency, is a value assesment. 'Your personal comfort and way of life is unacceptable if you do not conform to my political idealogy and support my causes'. That is why they often border on the rediculous, the mindset is so entrenched that anything not deemed valueable in thier world view is automatically declared wasteful under a catch-all excuse of energy conservation and "saving the world".
Re:Not a good use of energy by vandan · 2004-03-15 18:50 · Score: 1

Yeah. Like a chicken with 3 legs.
Didn't you read the article on Chernobyl?
With a half life of hundreds of thousands of years, we simply don't have a safe solution for the waste. And Uraniam, while being relatively abundant now, is not a renewable source of energy. We'd be better off investing in a renewable source and avoiding the risk of more radioactive contaminations.
Re:Not a good use of energy by Anonymous Coward · 2004-03-15 19:09 · Score: 0

Hypocrite.
The SUV's aren't gas guzzlers. Most Petroleum goes into other industries eg. Plastic. SUVs are another one of those "save every little bit" things. Besides, none of the energy we harness is being 'wasted' as eco freaks may have you believe. If that were the case matter would be forming due to E=MC^2. The only reason to stop using petrol is because we use it much faster than it gets remade. In summary, I say we invent fission and use it.
Re:Not a good use of energy by RoLi · 2004-03-16 00:51 · Score: 1

While the additional speaker might indeed be neglectible, the whole matter of running overpowered, hot CPUs running idle while waiting for the harddrive is not. This truely is idiotic.
You can get a fanless CPU from VIA which runs at up to 1GHz (plenty for most uses) and uses AFAIK about 20 Watts. And it isn't expensive either (I payed 140 Euros for both motherboard and CPU)
Of course less moving parts also mean more reliability.

Nope by Sycraft-fu · 2004-03-15 14:19 · Score: 4, Insightful

Sound is a wave, specifically a compression wave. It is fluctations of air pressure, which your ear interprets. You can see this in how speakers work. They vibrate back and forth to produce compression and expansion waves. Well, as with all wave dynamics, if you hit a wave with it's opposite, it cancels. Quite simple to think of why with sound. You have a high pressure peak and an equal low pressure peak that collide. The net effect is zero pressure (in relation to ambient atmospheric pressure).

Now if you screw it up and don't time it right, yes, you could increase the sound. However provided your system is indeed doing it's job and producing opposite waves in correct time alignment, it cancels out.

Try it yourself some time. Take two identicle speakers and feed them both the same sound (as in one mono sound to both channels, not a single stereo source). Reverse the polairty on one speaker (plug the black plug into the red and vice versa). If you have them setup normally and listen to the sound far away, it'll simply sound defocused, as though it has no apparent centre or source. This is a good way to focus your speakers, the more defocused an out of phase sound is, the more in focus an in phase sound is. However now take them, get them right next to each other, and point them at eachother. You'll hear almost nothing. PRetty much all you hear is the sound that radiates from the cabinets.

I use this trick when I'm burning in speakers. New speakers come from the factory with everything a little tight, as everything does new. Over the first month of playing they slightly change their sound as they get to their normal "burned in" point. It reach it quicker, you can just pump some white noise through your speakers. Well loud white noise is likely to piss off the neighbours, so I invert one speaker and have them face each other. Reduces it to a pretty minimal level and gives the speakers the desired workout.

Re:Nope by Reverberant · 2004-03-15 14:28 · Score: 0

New speakers come from the factory with everything a little tight, as everything does new. Over the first month of playing they slightly change their sound as they get to their normal "burned in" point.
You know the whole "speaker burn-in" thing is pretty much a myth, right? (unless you literally burn out your speaker!)
Re:Nope by Sycraft-fu · 2004-03-15 14:39 · Score: 1, Offtopic

No, they mesurably change sound slightly (at least the ones I like). I've checked with actualy measuring equipment. It's not much, I'm not sure I could pick it out in a blind A/B test, but it's real. I figure why not? Doesn't hurt anything, and ensures that the sound isn't going to change on me. I use my speakers quite a bit for mixing and mastering, so I need the sound to be consistent.

You'll also notice that your articles are talking about CABLE break in. Yes, that is a crock of shit, as are high end cables. I use normal braided copper wire in nice sheaths. Speakers are a different matter. They are actual moving parts. As such there is a slight difference in stiffness at manufacture than after some work.

I'm not going to run around claiming that all those who have never burned in their speakers are missing out on some awesome experience. Speakers burn them selves in with normal use. It's simply to give them the equivalant of a bit of use to normalize the sound and get past any slight changes that are going to happen.
Re:Nope by Anonymous Coward · 2004-03-15 14:43 · Score: 2, Insightful

Even more amusing than the supposed audiophiles who believe their speakers should be burned in are those who believe that solid-state electronics and even cables should be burned in. They buy (or download via BitTorrent nowadays) CDs from scam artists that supposedly contain "precisely computed noise" that stresses their equipment just so. It's really quite hilarious, if pathetic.

I have disgustingly acute hearing, perfect pitch, and have listened to a hell of a lot of music of all kinds, and I still find all of these sorts of audiophile claims to be hokum. It's an entire industry founded on lies and bullshit elitism. So frankly, let them waste their money - they deserve it.
Re:Nope by Reverberant · 2004-03-15 14:51 · Score: 0, Offtopic

You'll also notice that your articles are talking about CABLE break in.
Well some of the articles talk about cable break-in, but the search brings up several speaker-specific articles (for exmaple, the topic "Speaker burn-in question"). Dick Pierce's comments are particularly insightful.
No, they mesurably change sound slightly (at least the ones I like). I've checked with actualy measuring equipment.
By how much? (and measured with what?) Enough that the difference can't be attributed to humidty, temperature and ambient pressure differences? Speaker drivers are generally "burned-in" for several hours at the factory as part of the Q/A checks. Any more is redundant.
Re:Nope by Sycraft-fu · 2004-03-15 15:23 · Score: 2, Informative

1-2dB at certian frequencies (yes, at the limit of what you can hear different) and with a studio dB metre/spectrum anaylizer (don't remember the brand). It was in a studio, under ground, climate controlled, in the desert in the summer, so fairly consistent conditions.

Also, it eliminates the smell. New B&W speakers produce an odd smell when you shake the air up in them (ie whenever there is any significant amount of bass). Do it enough and for long enough, it goes away.

This solves that and will break in the speakers, assuming they need it.

Look I won't say for certian that the changes were a result of breaking in the speakers. However, I believe it to be the case. Either way, it costs nothing and deals with another problem.

Voodoo shit like buying $1000 speaker cables or spending lots of money on sand pads for my amp that are contrary to what I know about science, I'm NOT going to do without reliable emperical evidence to suggest it does something. However something simple like speaker burn in which is free (other than minimal electric costs), I have some empricial proof (though not conclusive), and DOES appeal to what I know about science, I'll continue to do until I see solid emprical proof that it doesn't do any good.
Re:Nope by r_jensen11 · 2004-03-15 15:25 · Score: 1

Meh, I still like my turntable. I just wish that the records didn't cost an arm and a leg.... That reminds me, I've got to pick up some speakers some time. I'm thinking of a set of Klipsche (around $300 each...), so they're expensive for me (a student,) but not over-the-top-can't-hear-the-difference-between-$10 00-and-$1500-speakers.

Oh, and why would anyone that thinks mp3's and the like think they're an audiophile? Honestly, if you're a true one, you'll stick with vinyl, not with 320kb/s MP3's, or worse yet, saying that 128kb/s MP3's are truely CD-Quality, and thinking that, even though they don't know that first statement is false, that CD's are better than vinyl in good condition....
Re:Nope by opec · 2004-03-15 15:28 · Score: 2, Interesting

This is a really neat aspect of sound waves. I saw an experiment once where two speakers were playing at each other, they tuned it until each completely negated each other and there was silence, though each was pumping out the tone. It applies to musicianship as well. Good marching bands with great intonation control can play really loud and sound good, while not so good bands will be limited in their maximum volume.
Re:Nope by Wehesheit · 2004-03-15 15:32 · Score: 0

so every pair of speakers is run for a few hours at the factory before being packaged and sent out? not bloody likely.

--
This P.I.G. will walk on the water, This P.I.G. will walk on the sea, This P.I.G. will walk whereever he wants.
Re:Nope by BlueJay465 · 2004-03-15 18:09 · Score: 2, Interesting

Listening to the differences in the different types of speakers and monitors working at a Guitar Center over the holidays, I was blown away by the sound quality of some of the studio monitors in their Pro-Audio department, and then comparing them to the high-end home-theater gear at the Magnolia Hi-fi just down the street.

You will get a lot more bang for your buck with a good set of monitors while only taking fraction of the space. Check out the Event TR series or M-Audio's line. Most decent music equipment stores like Guitar Center should have some demos.
Re:Nope by canowhoopass.com · 2004-03-15 18:20 · Score: 2, Interesting

Try it yourself some time. Take two identicle speakers and feed them both the same sound (as in one mono sound to both channels, not a single stereo source). Reverse the polairty on one speaker (plug the black plug into the red and vice versa). If you have them setup normally and listen to the sound far away, it'll simply sound defocused, as though it has no apparent centre or source. This is a good way to focus your speakers, the more defocused an out of phase sound is, the more in focus an in phase sound is. However now take them, get them right next to each other, and point them at eachother. You'll hear almost nothing. PRetty much all you hear is the sound that radiates from the cabinets.

This is one reason why I love Slashdot... you pick up all sorts of neat science project ideas for the kids. Thanks!

Rod!
Re:Nope by Ralph+Wiggam · 2004-03-15 19:38 · Score: 3, Interesting

Seperating audiophiles and thier money is like shooting fish in a barrel. I think there is a lot of placebo effect in high end audio. You just paid 800 bucks for a few meters of cable. It was a multi-thousand dollar system before the new cables. Do you think it could sound bad now?

I'm lucky. I have very good hearing, but I'm pretty tone deaf. The medium priced stuff at Best Buy sounds just as good to me as the high end stuff at the specialty stores. There's no point for me to shell out the cash.

-B
Re:Nope by sweede · 2004-03-16 00:41 · Score: 2, Informative

I beleive Alpine and I know MB Quart does this, two of the highest quality car audio speaker manufacturers.

--
I follow the SDK and GDN principles.. Spelling Dont Kount, Grammer Dont Neither
Re:Nope by hackstraw · 2004-03-16 04:11 · Score: 1

Seperating audiophiles and thier money is like shooting fish in a barrel. I think there is a lot of placebo effect in high end audio. You just paid 800 bucks for a few meters of cable...

In defense of audiophiles (I'm a recovering audiophile :), I would believe that 800 bucks for a cable is an exaggation, but there are many audiophiles that when they put together a system, they do it by percentages of what they are willing to spend. Typically, its 50% of the budget for speakers, 40% on electronics (amps, cdplayers, etc), and 10% on interconnects and cables. 10% is not an excessive amount for a large purchase, and it would be stupid to spend 5, 10, or 20 grand on an audio system and be too cheap to spend a couple extra dollars for better cables. With the above percentage of 10% on cables and the above budgets this would be $500, $1,000, and $2,000 for cables.
Re:Nope by Martin+Blank · 2004-03-16 06:08 · Score: 1

Well, as with all wave dynamics, if you hit a wave with it's opposite, it cancels. Quite simple to think of why with sound. You have a high pressure peak and an equal low pressure peak that collide. The net effect is zero pressure (in relation to ambient atmospheric pressure).

OK, now that you explain it that way, it makes much more sense as I visualize it. I had always thought of it in terms of sine waves, where adding an opposite to a display merely doubles the amount of light coming from the screen, rather than in physical terms of what the molecules were doing.

I guess I need to spend less time looking at screens and more time standing in the wind. :)

--
You can never go home again... but I guess you can shop there.
Re:Nope by Kiyooka · 2004-03-16 07:03 · Score: 1

Well, as with all wave dynamics, if you hit a wave with it's opposite, it cancels. Quite simple to think of why with sound. You have a high pressure peak and an equal low pressure peak that collide. The net effect is zero pressure (in relation to ambient atmospheric pressure).

Maybe not all wave dynamics. Water waves can go right through one another and not slow down or be diminished!
Re:Nope by StateOfTheUnion · 2004-03-16 08:10 · Score: 1

Maybe not all wave dynamics. Water waves can go right through one another and not slow down or be diminished!
So can sound waves. Waves are additive. They only cancel each other out when they are out of phase with one another. You can cancel out a water wave with another wave that is the opposite of the first wave (100% out of phase; same magnitude and direction) . . . but this probably does not happen very often in natural bodies of water (and if it did, there would not be much to see . . .)
Re:Nope by Anonymous Coward · 2004-03-16 08:48 · Score: 1, Funny

Reverse the polairty on one speaker
That's odd, I though Wil Wheaton posted on /. as CleverNickName.

woosh would be hard to cancel by nomel · 2004-03-15 14:19 · Score: 3, Insightful

cause it varies depending on listenning angle, where the whine is pretty constant.

probably why he's having trouble.

Re:woosh would be hard to cancel by flappinbooger · 2004-03-15 14:31 · Score: 1

If the whoosh is from the air movement itself, might be hard to cancel it.
Particularly if the noise is from the air entering and exiting the case, the gear inside might not pick it up. He would need a similar system to cancel the noise of the air at the front/back of the case.
Then, why not just cancel all the noise from the outside, whoosh and all? Heck, get a set of noise canceling headphones and cancel the whine, whoosh and all the other noise?
I think I took it too far...

--
Flappinbooger isn't my real name
Re:woosh would be hard to cancel by HonkyLips · 2004-03-15 14:35 · Score: 1

My own recommended solution is to go down to the hardware shop, buy a can of poly-urethane foam in a can, stick the nozzle inside your case, and pull the trigger until it is completely filled up with foam. Works for thieves who need to silence alarm sirens....

--
Putting syrup in coffee is some form of blasphemy.

I've used the headphones that do this... by Phil+John · 2004-03-15 14:20 · Score: 2, Interesting

...as a pilot friend of mine has a pair (with mic boom as well). When you are flying a Cessna it's hard as hell to hear air traffic control, so these really help.

One really important use of these will be in ultra-quiet studio computers. Of course, its not to make sure the fan noise doesn't get recorded as its not a real recording studio if there isn't a separate recording booth/room (the studio I use in london from time to time is two rooms built within one large one, resting on a buttload of industrial springs, but I digress.

When you are listening to playback, making sure the singer was in tune, mixing the track, or whatever, you don't want ANY extraneous noise from fans. There is already a market for ultra ultra quiet pc's for this kind of application and advances like this can only help further the art.

--
I am NaN

Re:I've used the headphones that do this... by wildsurf · 2004-03-15 20:22 · Score: 1

When you are flying a Cessna it's hard as hell to hear air traffic control, so these really help.

I recently took a helicopter tour of Kauai, and the passengers were given noise-cancelling headphones with closed-circuit audio so we could hear the pilot and talk to each other during the trip. Made a tremendous difference in enjoying the ride, and allowed us to concentrate on the scenery rather than the noise.

Now, if only they'd had motion-sickness-cancelling headphones for my poor girlfriend...

--
Weeks of coding saves hours of planning.
Re:I've used the headphones that do this... by gravelpup · 2004-03-16 03:18 · Score: 1

...as a pilot friend of mine has a pair (with mic boom as well). When you are flying a Cessna it's hard as hell to hear air traffic control, so these really help.
IAAP and I have a couple pairs of these. They are fantastic in the cockpit. I wish I could wear them at my real job -- my cube is next to the copier and the conference room (someone here really doesn't understand how programmers work). Unfortunately they are huge and I'd look like a complete wack.
I'd imagine it's a lot easier to design noise reduction for airplanes than for an office-type environment. The noise in the cockpit is at a relatively constant frequency and amplitude (engine drone plus wind noise), so they can take some shortcuts.

--
Things are more like they are now than they ever were before.

More or less by Sycraft-fu · 2004-03-15 14:22 · Score: 1

There's a bit more to it, since you need to make sure that it is time synched with the orignal sound. If it's not, it won't work as well (or at all).

but... by Anonymous Coward · 2004-03-15 14:23 · Score: 0

can it cancel the noise of a beowolf cluster?

Silent PC Review by PoisonousPhat · 2004-03-15 14:24 · Score: 5, Informative

No Slashdot post about computer noise is complete without a link to Silent PC Review.

--
Losers choose to abuse the use of "loose".

give me.. by Feyr · 2004-03-15 14:25 · Score: 1

i'll buy 5! where do i order?

Re:No need to worry. by NeoSkandranon · 2004-03-15 14:26 · Score: 1

Do the zalman HSF systems depend on airflow through the case for cooling?

What I mean is, if i put one in, am i also going to have to put new fans on my case itself to get ventilation to keep up with the zalman?

--
If you can't see the value in jet powered ants you should turn in your nerd card. - Dunbal (464142)

here's how to make it quieter for free by Anonymous Coward · 2004-03-15 14:29 · Score: 1, Informative

you can rewire your fan for 7v instead of 12v (unless you like to do monster 3D rendering sessions for a few weeks), drops noise drastically

just use the 5v line and the 12v line as + and -
(no earth) the voltage differential is 7v so you wont need to usa a resistor, if you still need large airflow then look at Panaflo fans (made by panasonic) 21db quoted @12v

see
this store for the most common fans

Sure by Sycraft-fu · 2004-03-15 14:29 · Score: 1

If you have the cash, of course. Bose did something like that for our football stadium. Whole new speaker system, part of it noise canceling. It's amazing to hear so little echo, given what stadiums normally sound like.

The same thing can be applied to any space, for a price. In the case of a house simple passive noise reduction (padding) is probably a better idea. However, if you've the money there are instutions that can help you setup a system like that.

Prior Art: The Fenton Silencer by Lew+Pitcher · 2004-03-15 14:30 · Score: 1

"Silence Please", (c) Arthur C. Clarke

Published in "Tales from the White Hart", Harcourt, Brace & World, Inc. (LCC Card# 76-95870)

--

"values of beta will give rise to dom!"

You're right! by Anonymous Coward · 2004-03-15 14:30 · Score: 0

NEC (in japan) has a water cooled computer now on sale to the teeming millions. water runs over the CPU and goes into a radiator to the back of the case.

I just tried this with my computer and it works! I took a cup of water and splashed it all over the backside of my computer, making sure plenty went in through the venting holes. And the damn thing isn't making any noise now!

Thanks slashdot!

SPCR by Anonymous Coward · 2004-03-15 14:39 · Score: 4, Informative

Someone send this guy a link to
http://www.silentpcreview.com

Implementing noise cancellation for poor quality whining fans seems ridiculous in comparison to replacing the fans with better quality ones.

Quote from SPCR -
" What is a good inexpensive & quiet general purpose fan?

The 80mm Panaflo FBA08A12L with "HydroWave bearing" is widely used and recommended for its combination of low noise (21 dBA), good airflow (24 cfm), wide availability (but not in Canada where I type this) and low cost. At 7V, it is almost inaudible in most applications. At 5V, it is inaudible but still provides some airflow. We think of it as a workhorse, suitable for use as a case fan, CPU heatsink fan, or PSU fan replacement."

Re:SPCR by Lonewolf666 · 2004-03-15 21:14 · Score: 1

For those in Germany, I can recommend Papst fans. They are a bit expensive but so far I have had very good success where I used them. They are not only quiet in terms of flow noise, but also well balanced so they cause less vibration in the case than cheap & shitty fans.

--
C - the footgun of programming languages

the best way to cancel pc noise... by mgoodman · 2004-03-15 14:44 · Score: 5, Informative

...is to buy Zalman components ( http://www.zalman.co.kr/english/intro.htm )

I built my last PC with their components. When I powered up for the first time I freaked out because I saw the power light go on, but that was it. Then the BIOS came up, thank god. No noise at all...seriously. I mean, I expected quiet, but not noiseless...

I was extremely let down by my hard drive though. Considering Seagate had a great reputation for quiet hard drives, I figured I'd get a Seagate SATA hard drive...well their SATA drives are loud as heck when writing...

--
01100111 01100101 01110100 00100000 01101111 01110101 01110100 00100000 01101101 01101111 01110010 01100101 00101110

Re:the best way to cancel pc noise... by Anonymous Coward · 2004-03-15 18:35 · Score: 0

why buy expensive stuff when you can buy cheap crap, cancel the noise, and it's as good as the expensive stuff?
Re:the best way to cancel pc noise... by mgoodman · 2004-03-16 04:58 · Score: 1

" why buy expensive stuff when you can buy cheap crap, cancel the noise, and it's as good as the expensive stuff?"

Because the cheap crap isn't as good as the expensive stuff...it's cheap crap.

Also, Zalman components are not very expensive. $25 bucks for a heatsink and fan that provides great heat dissipation and runs completely quiet really isn't all that much money. Sure, you could spend $10 bucks on a cheapo heatsink and fan, but it wouldn't provide the same level of heat protection or noise reduction.

The most expensive thing that I purchased from Zalman was my 400W PSU that ran me around $90. Sure, that's expensive for a PSU, but it's worth it. I don't mind putting out an extra $150 bucks for a noiseless PC -- it's better than dealing with a loud PC because of cheap crap components. And newegg.com will RMA it if you don't like it. Newegg rocks.

--
01100111 01100101 01110100 00100000 01101111 01110101 01110100 00100000 01101101 01101111 01110010 01100101 00101110

there are lots of applications for this by Anonymous Coward · 2004-03-15 14:44 · Score: 1, Funny

lets modify it to cancel out darl mcbride when he speaks

Re:No need to worry. by mgoodman · 2004-03-15 14:50 · Score: 1

If you buy one of those Zalman fan-shaped heatsinks it does depend on airflow within the case. If you are overclocking you really should have decent airflow. If not, and if the computer is stored in a cool environment, you should be fine.

Most Zalman heatinks (if not all) come with a fan, so you probably don't need to go out and get one (except for extra case fans if you are overclocking, which is practically useless nowadays). The fan provided is so quiet you can't hear it. Beats the hell outta Panaflo or anything else I've experienced. Zalman rocks.

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01100111 01100101 01110100 00100000 01101111 01110101 01110100 00100000 01101101 01101111 01110010 01100101 00101110

I did this, too, it works great! by Anonymous Coward · 2004-03-15 14:55 · Score: 0

Now, after some time, I just turn to look at the CPU and it stops the noise in fear.

WHAT?! by Intocabile · 2004-03-15 14:56 · Score: 1

So damn hard reading a computer screen with this cone of silence on. No annoying fan noises though.

Cancel out Darl's noise by spectasaurus · 2004-03-15 15:04 · Score: 0, Redundant

Being from Utah, it'd be nice to get something to cancel out Darl's noise.

new idea, or new application? by quick_dry_3 · 2004-03-15 15:05 · Score: 1

is this really a 'new' idea, or just a new application?

I'm sure there have been plenty of active noise cancellation devices built around these principles for ages.

The car one that someone else mentioned, sampling road noise and playing back an out of phase sound. I thought I'd read something about this also being used in aircraft cockpits to allow for clearer comunications as you'd be removing the engine noise... or just create a cone of silence to allow you to sleep at night if you're near a busy road.

Re:There is risk involved with this by Anonymous Coward · 2004-03-15 15:07 · Score: 0

If the fan fails short circuit you can end up causing some serious damage with this "trick" however.

The risk is low, but its good to be informed of the risk.

Simpler Solution by Anonymous Coward · 2004-03-15 15:08 · Score: 0

Noise cancelling, cutting fan voltage, water-cooling...

Has anyone ever tried sound-proofing their case?

hard drive whine by mrm677 · 2004-03-15 15:08 · Score: 1

I find that the hard drive noise is much more annoying. At 7200RPM, the noise is higher frequency than a cooling fan operating at 1500rpm or so.

And I just replaced a hard drive simply because the whine got too loud due to the bearings getting old.

Re:hard drive whine by BCW2 · 2004-03-15 16:29 · Score: 3, Informative

Try Maxtor's fluid bearing drives. In an old AT box the only way I knew the drive was being acessed was the case fan slowing down. I now have 2 in my current box, along with Panaflo Low case fans (80mm and 92mm) and AMD's own heatsink and fan on a 2000+. Very quiet for the performance. Also check out the Volcano 10 heatsink and fan, thats quieter than AMD.

--
Professional Politicians are not the solution, they ARE the problem.

I'm just going to say it by Anonymous Coward · 2004-03-15 15:14 · Score: 1, Insightful

This is how I think it should be. We go down to the point where processors are low power enough we don't need active cooling and we add power within those constraints. To get more power we just add more processors. So for like a powerful desktop we could have 4 or 8 fanless processors...

And we'll all be yeomen farmers in 2012.

But seriously, isn't it obvious chip manufacturers have relied increasingly on "overclocking" their chips in order to show meaningful performance gains? It's a clear indication that the current trend in microprocessor performance has levelled off. More and more exotic cooling solutions are required for even the most humble new PC. What ever happened to the 486 days when we didn't need heatsinks for the top of the line machine?

Re:I'm just going to say it by Anonymous Coward · 2004-03-15 16:11 · Score: 0

Well Intel and AMD are guilty as charged, but check out VIA's offerings. They sell surface-mounted mobos with CPU heatsink only. Sure, they're not as fast as Intel or AMD, but I'm using one as a development box right now, and it's quite fast enough for my purposes. Mind you, I'm not a hardcore gamer or into 3D graphics or whatever. But for normal desktop or console use, they fit the bill nicely IMO.

Dude, It has been done in INDIA by timlyg · 2004-03-15 15:18 · Score: 0

In India, you can see in personal homes, homemade wave cancelling boxes. They are rather big, and external, but they do the job.

Stick to the jet engine thing.

Not a new concept ... by scdeimos · 2004-03-15 15:23 · Score: 3, Interesting

... just a new application.

Before CPU's came along, this sort of thing used to be done with BBD (Bucket Bridge Delay) circuits, replaying the sampled sound 180 degrees out of phase. Of course, this only worked with single-frequency tones and the BBD had to be clocked at just the right correct frequency. Cancelling white noise (ie: fan whoosh) is a somewhat more difficult problem.

A number of "professional" aircraft pilot communications headsets have had active-cancelling (as in the article) built into earpieces (as opposed to the microphones) for several years, so as to reduce engine noise and pilot stress.

Car buffs here might even remember that VW had a Concept Car in the nineties which had an (I think) Bose-powered active-cancelling system in the cabin, the purpose being to cancel road noise and engine bay noise so you could replace it with sound samples of your favourite sports cars: Ferrari's, Porsche's, etc. Not sure it ever took off, though. ;)

So how do I make one of these? by myov · 2004-03-15 15:33 · Score: 1

I have a rather *loud* nortel switch would could really benefit by one of these. Is it microphone into soundcard with some sort of inverter, or is it built from electronic parts? Would a backwards wired microphone and amplified speakers work?

And how do I position the speakers?

--
I use Macs to up my productivity, so up yours Microsoft!

Results will vary with frequency by sammyo · 2004-03-15 15:41 · Score: 2, Insightful

This is not a new idea and with a fairly constant tone may be possible but a complete solution for any frequency, direction, range and environmental configuration will be incredibly hard. Different frequencies will bounce and be absorbed by different materials, ah differently. ;-) So unless the damping tone is generated from the precise location as each 'annoying sound, a different calibration may be needed.

MOD UP +5 Fascism by Anonymous Coward · 2004-03-15 15:58 · Score: 0

"Wouldn't it be fun to CENSOR our opponents!"

Slashdot Libertarians, my butt. Buncha jack-booted GNU/Stalinists.

This is so fucking old by Anonymous Coward · 2004-03-15 16:05 · Score: 0

I saw a show about this exact same technology in the late 70's on TV in the UK. Playing out-of-phase sound to cancel sound is NOT new. This guy didn't invent a thing.

Efficiency is pretty low though by tentimestwenty · 2004-03-15 16:24 · Score: 1

Most speaker drivers aren't nearly accurate enough to completely cancel out a particular sound or frequency. They're just too slow and have weird dispersion characteristics. About the only speaker that's ever been really good at it is the Quad electrostatic (any incarnation). They used to demo the accuracy of their speaker by playing a sine tone with one speaker out of phase and having a microscope attached to an oscilloscope. There was no sound at the listening point because the thin plastic drivers were so fast and directionally stable that even at distance they could maintain accuracy. Most people after hearing them will also think they sound as close to real sounds as possible for the same reason.

Can they shut up SCO? by Stonent1 · 2004-03-15 16:25 · Score: 0, Redundant

Since this is all talking place at Brigham Young University, can they apply this noise cancelling technology to our old buddy Darl and his henchmen err lawyers?

Re:No need to worry. by macklin01 · 2004-03-15 16:52 · Score: 1

That's a good strategy. An efficient heatsink with a quiet fan can go a long ways. I installed a Thermalright SP-94 (all-copper with heatpipes) with a 92mm Panaflo M running at 8V. It keeps my P4 3.0C (overclocked to 3.5 GHz) pretty cool and pretty quiet. My GF Ti4200 is passively cooled with a Zalman heatsink. My current power supply is pretty quiet, but I fixed my old one up by removing the airflow-restricting punched vents with a Dremel and replacing the cheapo loud fan with a quiet Panaflo L. Also added a direct intake of airflow right about the CPU / HSF in the side of a case with an 80mm Panaflo L running at 7V.

It's amazing how quiet this system is. It's even quieter than my previous PIII system was at half the speed. Up until recently, it was much quieter than my wife's HP Celeron 800 system. (We just finished modding that together to quiet it down...)

Really, if you're willing to put in a little bit of elbow grease and research here and there, you can wind up with a high-performance system that's quieter than most OEM systems.

Oh, as for hard drive noise that was mentioned above, the trick to try is to mechanically isolate the hard drive from the case, such as by suspension. See www.silentpcreview.com and www.overclockers.com for some ideas. :) -- Paul

--
OpenSource.MathCancer.org: open source comp bio

Interesting Interesting by xintegerx · 2004-03-15 16:57 · Score: 1

Bose noise cancelling headphones suck, they aren't even the best active noise cancelling headphones available.

If not being #1 at every thing means you suck, then you must live a very depressed life. :O

--

Cover your eyes and click this link!

Make fans with predictable noise? by noidentity · 2004-03-15 16:57 · Score: 2, Interesting

I wonder if the cooling fans themselves could be designed to make more predictable noise, such that noise cancellation could be done without a mic, and synchronized to the fan via the rotation sensors.

Really big fan noise by Animats · 2004-03-15 17:00 · Score: 1

I was just out back of PAIX, the Palo Alto Internet Exchange, Silicon Valley's major Internet switching and peering point. It's hot today, and the fan noise was loud enough to make conversation in the parking lot difficult.

And you thought you had noise problems.

why bother ... by cwg_at_opc · 2004-03-15 17:07 · Score: 3, Informative

when zalman have a fanless case:

THGs review of the TNN500A

THG sez you can still hear(barely) the HDD and optical, but if you're a noise weenie, do like the govt and replace everything with solid state(HDD and use CF for transportable media)
The case is stupid expensive at $1400US and the adventurous could probably build one for less by cannibalizing heat pipes from VGA coolers and stripping heatsinks from dead hifi amps, but there are ways of reducing PC noise without killing yourself or your bank account:

case - antec sonata or slk3700bqe

PSU - antec's yet-to-be-released phantom 350W PSU, or check this list:

SPCRs list of PSUs

using vibration absorbing grommets for everything that vibrates(HDD, Optical, fans, etc.)

quieter fans:

SPCRs fan list

OR, get longer cables and put the machine in an airconditioned closet; with a long USB2 cable and a powered hub, you might never hear your machine again. it'd just be you, your KB, monitor and a 7-in-1 media reader.

--
"...that's as white as it gets; all the bits are on..."

RE : Cancelling Out CPU Fan Noise by Gitcho · 2004-03-15 17:08 · Score: 1

It isn't perfected yet -- it only nixes the whine, not the whoosh I actually don't get much whoosh ... it's the constant whine telling me to "get off my computer" that seems to cause the most trouble ... heh heh .. just kidding honey :) c'mon ... someone had to say it !

what an amateur by MikeRfactor · 2004-03-15 17:11 · Score: 2, Informative

your only solution is to do what I'm doing,

put all the computers in a rack downstairs, cut a hole in the ceiling and the floor, and run the cables up to the second floor office!

*fire pole sold separately

I have a better and cheaper solution... by Scratch-O-Matic · 2004-03-15 17:21 · Score: 4, Funny

I've constructed a simple device that cancels almost all noise from my fan. A common #2 pencil inserted into the fan blades does the trick quite nicely. I've used this system sucessfully on three different computers, and I can tell you that the noise reduction is dramatic. Oddly, all three of them stopped working within minutes due to unrelated problems.

--

Evil is the money of root.

Re:I have a better and cheaper solution... by marcellos · 2004-03-15 22:23 · Score: 2, Funny

Next time try inserting the #2 pencil in your ears. (Crayons are more confortable though). It also works well, and your computer keeps working...

Making a quiet comp is not easy... by protohiro1 · 2004-03-15 17:33 · Score: 1

see silentpc review for more info on how complex it can get. Read the forums to see how anal some quiet pc enthusiasts can be.

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Sig removed because it was obnoxious

Then polygamy must be great by Begemot · 2004-03-15 17:38 · Score: 1

2 wives would cancel their own noices

This is why they havent gotten rid of the "whoosh" by Ayanami+Rei · 2004-03-15 17:40 · Score: 2

The whine of the fan is due to vibrations caused by the inefficiency of the particular design, and manufacturing defects in the fan or it's mounting. A "perfect" fan would be silent except for the sound of moving air.

They haven't gotten rid of the whoosh sound yet; canceling out the whine while still leaving the sound of moving air is probably a good sign that air is still moving :-) If the managed to someone completely mask the sound, then I'd start worrying about air flow reduction (although I'd start by moving my head around the fan port first, to see if it's just perceptual)

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THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

Imagine 8 CPUs, 24 HDs, 48 fans and no noise! by commonloon · 2004-03-15 17:42 · Score: 0

Want to buy some swamp land?

Except in the case of noise canceling headphones.. by Ayanami+Rei · 2004-03-15 17:44 · Score: 1

...there's only one set of speakers. They use a circuit to electronically subtract the external mic-noise to the analog audio signal before sending it to the voice coils. Hence no need for acoustic preservation of energy, nor superposition of speakers to achieve the desired effect across all audible frequencies.

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THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

Re:Just do what I do by wafflemonger · 2004-03-15 17:48 · Score: 1

I tried that once and my pc got really quiet.

Just like the sound barriers next to US highways by Ayanami+Rei · 2004-03-15 17:50 · Score: 1

I've got these behind my house Works wonders.

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THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

Mod up! by Ayanami+Rei · 2004-03-15 17:56 · Score: 2, Interesting

We're currently doing experiments monitoring this at work. We want to isolate engine vs. tire vs. transmission noise across various makes and models of cars during ramp up, idle, and braking. It's a fun project involving lots of wireless and embedded tech, with audio, sig proc, and linux thrown in there too to make it interesting.

From what little of the results I've looked at, it's pretty clear that tire noise is dominant during cruise.

--
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

WOULD YOU ALL KINDLY SHUT THE FUCK UP? by Ayanami+Rei · 2004-03-15 17:59 · Score: 1

I'm trying to sleep. Not only do you have to wake up the whole goddamn neighborhood with your obnoxious shit-cars, but you have to pull over and start carrying on about it on my FUCKING LAWN.

GET OFF MY PROPERTY!!!

--
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

I replaced my dual pentium pro 200 monster... by Ayanami+Rei · 2004-03-15 18:03 · Score: 1

(2x200MHz w/ 512MB of RAM, mind you) with a dual PII400, and then shortly after, a 866E Celeron.

The celeron is the fastest out of all of them. It's also the smallest and quietest.

--
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

Re:I replaced my dual pentium pro 200 monster... by Endive4Ever · 2004-03-16 13:55 · Score: 1

Depends on your definition of 'fastest' I guess.

My server has four PPro 200s, and dual SCSI RAID arrays.

Bandwidth, mon, not how fast the processor can run little bitty programs in it's cache.

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That's retarded. by Ayanami+Rei · 2004-03-15 18:17 · Score: 1

You want a flower or a slotted radiator. Ensure the motherboard layout allows the heatsink oriented so that the openings face towards the I/O plate.

Install a big-ass 120mm, god-like cu. ft per min fan above the IO plate, and mount it with rubber fasteners, if available.

Feel free to use the low-RPM mode of the main cpu fan, because the large case fan will be doing most of the air moving (pulling it across the fins from the northbridge side of the motherboard). You can probably fashion an air hood to ensure the airflow goes only through the CPU heatsink and ditch the main CPU fan, if you're clever.

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THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

Cure for Tinnitus? by kinyobi · 2004-03-15 18:28 · Score: 1

People with tinnitus would appreciate if the ear ringing could be alleviated with this sort of technology.

Noise Cancelling, eh? by TACNailed · 2004-03-15 18:44 · Score: 1

My question is: Will it work on my parents?

He couldn't just buy a Mac? by Lord+of+the+Fries · 2004-03-15 18:46 · Score: 1

Well, excepting the wind tunnel known as the G5 XServe, that is.

--
One man's pink plane is another man's blue plane.

Hmmm... by troon · 2004-03-15 18:58 · Score: 1

Well, I do have a PhD in physics [...]

[...] a gazillionth of a watt

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Ydco co ,df C erb-y go. a Ekrpat t.fxrapev

Ears are sensitive indeed! by chadjg · 2004-03-15 19:04 · Score: 4, Interesting

My acoustics book said that if you put a person with normal hearing into a sound isolated anechoic chamber, and give them awhile to adjust, they will actually hear the blood flowing in their ear.

Point being is that it would be completely pointless for them to be any more sensitive. Quite amazing really.

--
Why do I have this? I don't smoke.

Re:Ears are sensitive indeed! by ziggy_zero · 2004-03-15 20:27 · Score: 4, Informative

It should be noted that the flow of blood, chewing, other internal sounds, etc. would be a LOT louder if we didn't have the middle ear. One of its (theoretical) functions is to reduce the transmission of bone-conducted sound to the cochlea.

/trying to see if I can actually interject something I learned in my music psychology class into a conversation....

--
I belong to the ______ generation.
Re:Ears are sensitive indeed! by TwistedGreen · 2004-03-16 01:05 · Score: 3, Funny

The logical next step, then, is to evolve quieter blood!

Noise Cancellation in Powermac G5 by amsr · 2004-03-15 19:07 · Score: 5, Informative

The fan controller in the Power Mac G5 is aware of the noise amplifying and canceling effects of running different fans at different speeds in different combinations. It actively uses this information and uses it in decisions on how to cool the G5 in the quietest manner using the 9 strategically placed fans.

Re:Noise Cancellation in Powermac G5 by Anonymous Coward · 2004-03-15 23:44 · Score: 0

I bet you had an orgasm writting that.

Re:Nice in theory... by symbolic · 2004-03-15 19:09 · Score: 1

But right now, I have both my drives unmounted, as I was in the process of transferring the contents of one drive to another, after which I would have replaced one of them. Turns out, the noise is every bit as bad whether it's being transmitted through the case or not. If you see that much attentuation, it might be due to the noise-deadening qualities of the foam, rather than its ability to keep it from being transmitted through the case. I hope I'm not just engaging in semantic hair-splitting, because that's not my intent.

Time to file a patent. by glenalec · 2004-03-15 20:31 · Score: 1

Method of alerting pedestrians to the approach of a silenced automobile.

Basicly, an ice-cream van bell-pianola attached to the fan belt.

Ding Ding Dingty Ding....

--
The man with no surname and a silly hat

On the universe: It's bunk.

Traffic noise? by Anonymous Coward · 2004-03-15 20:47 · Score: 0

Will this noise reduction method work with traffic noise? I live pretty close to a highway, and the noise from cars driving by drives me crazy. Do you think it is possible to use microphones and speakers to cancel out the sound coming in, or is the noise to varied to deal with?

Re:Traffic noise? by DragonTHC · 2004-03-15 21:31 · Score: 1

noise cancelling will work with anything.

the key to cancelling is to invert the wave and play it back. it then cancels itself out.

--
They're using their grammar skills there.

Let's give it its proper name by Anonymous Coward · 2004-03-15 22:30 · Score: 0

Anti-noise ..
http://www.freesearch.co.uk/dictionary/anti-no ise

Lotus have been using similar technology in their sports cars for some time. See also Bose noise cancelling headphones for use on aircraft.

They said cars will have this technology ... by Anonymous Coward · 2004-03-15 22:58 · Score: 0

They said cars will have this technology over 5 years ago. They showed us working prototypes ...

SO WHERE IS IT? Don't hold your breath waiting for this technology either.

BTW: My "active" ear-muffs block rifle shots really well using the same technology and they are over 10 years old.

But...how... by DunbarTheInept · 2004-03-15 23:00 · Score: 1

I've heard of this concept used to cancel the noise of moving the big airplane lifts in aircraft carriers too (it echos around inside the big room under the deck, making an intolerably loud sound down there.)

But, what I don't get about these is ... HOW? It seems to me that if you need to measure phenonenom FOO to decide how to cancel phenomenon FOO, then you just got rid of the thing you need to sample to do the getting rid of it - a chicken-and-egg problem it seems.

Somewhere the sound has to be detectable, at its full original amplitude, so you can calculate what sound wave to send to the speaker, AND how strong it should be (No sense sending an opposite wave that's twice as strong as it needs to be and thus creates pretty much the same sound back out again - so you do need to be able to hear the sound at its original volume at some point in the system.)

--

Don't label something "offtopic" unless you know the topic well enough to tell what's on topic.

Idiotic analogy award by ArseneLuppin · 2004-03-15 23:02 · Score: 1

It's hard to think of loudspeakers creating silence. Sommerfeldt said it would be like placing conventional speakers in an air vacuum, where the speaker cones would vibrate but produce no sound.

Yeah whatever. In this analogy, the speaker would produce no sound, but it would not create any silence (the silence was already there before).

Mr Smart tech reporter: if it's too hard for you to think about loudspeakers creating silence, then please simply don't think about it, rather than spreading non-sense. Leave the thinking to those who don't find it as hard!

Arthur C. Clarke wrote about this in 1950 by ronys · 2004-03-15 23:54 · Score: 1

In a short story entitled "Silence Please", first published in Science-Fantasy #2, 1950, later in a collection in 1957, "Tales from the White Hart" (reprinted in 1970 by Harcourt, Brace & World Inc., New York).
Quite funny, even if he does take some liberties with the laws of physics.

--
Ubi dubium ibi libertas: Where there is doubt, there is freedom.

serious question for the scientists by Anonymous Coward · 2004-03-16 00:30 · Score: 0

say theres all this crazy cancellation of waves and stuff going on all around you and you start to scream *AHH AHHHH!*...do you think your brain would blow up?

//brain

OT - graphics card fans and indication of death by Anonymous Coward · 2004-03-16 00:44 · Score: 0

This is wayyyy off topic from the rest of the discussion. I was wondering. If your graphics card fan dies, does the software you run or driver give any kind of indication or does it simply just crash on you when playing games?

A Cheaper Way by Kombat · 2004-03-16 01:48 · Score: 4, Interesting

My acoustics book said that if you put a person with normal hearing into a sound isolated anechoic chamber, and give them awhile to adjust, they will actually hear the blood flowing in their ear.

An even cheaper demonstration is to simply plug your ears. It works better in an area that's already quiet, but if you simply plug your ears with your fingers, you'll hear the blood flowing in your veins and arteries. That's what that low, rumbling noise is that you'll hear.

--
Like woodworking? Build your own picture frames.

Re:A Cheaper Way by thelenm · 2004-03-16 05:17 · Score: 2, Funny

Isolated Quiet Area: free
Index Fingers: free
Veins and Arteries: free

Watching all of Slashdot sitting in a corner and sticking their fingers in their ears: Priceless.

--
Use Ctrl-C instead of ESC in Vim!
Re:A Cheaper Way by Perky_Goth · 2004-03-16 07:56 · Score: 1

wow, i never knew...
trivia rules :)
Re:A Cheaper Way by The+Tweaker · 2004-03-17 04:09 · Score: 0

I used to hear ringing when I plugged my ears now all I hear is this damn blood rushing sound! Where's the bathroom?

THANKS A LOT!!

A low-tech solution by ttsalo · 2004-03-16 01:51 · Score: 1

I installed suitable potentiometers in series with my CPU fan and three case fans, and then just adjusted each of them down until the fans were quiet enough. You don't actually have to back down that much from the maximum rpm to get the noise level way down.

The power supply is one of those extra quiet ones and the HD is in a an SilentDrive enclosure that fits into the 5.25" rack. Took a while, but now things are pretty quiet. Even my laptop's fan is noisier than the whole desktop computer. Until I boot to Windows for video editing and my RAID disks spin up, that is...

--

--
If the road to hell is paved with good intentions, where does the road paved with evil intentions lead to?

speaking of your girlfriend by gosand · 2004-03-16 02:10 · Score: 1

Could be a useful mute tool for the girlfriend when she goes on too long:

Heh, I thought of this in a totally different way. But that is just me. And your girlfriend.

--

My beliefs do not require that you agree with them.

Re:Just do what I do by Theaetetus · 2004-03-16 02:29 · Score: 1

Just do what I do, don't use a CPU fan! My PC is nice and quiet.

Likewise! And my laptop stays perfectly silent, too!

-T

Been There, Almost Done That by Wingsy · 2004-03-16 02:54 · Score: 2, Interesting

As an EE I had the "opportunity" to design an active noise cancellation system for headphones to be used in aircraft. I had the perfect test bed - my own plane, an Emigh Trojan. Loudest cockpit noise in the world. Anyway, the technique seemed simple enough - place a mic outside the earpiece and apply the outside noise to the earphone speaker, phase adjusted by whatever was required to cancel the outside noise striking the eardrum (a single point). The problem was that every frequency (or small range of frequencies) needed its own amount of phase shift, which complicated matters tremendously. The phase shift needed, due to the wavelength "distance" between the mic and the eardrum, was not right on 180 degrees like one might think. The final "product" helped quite a bit but was still not something I would want to try and market (which it wasn't). If you notice in the article, NASA also gave up on designing a noise cancellation system at airports. The problem NASA faced was much more difficult than mine. The source of the noise and the eardrums of the receivers were never in one fixed location. So, not only did they have to apply a phase shift to several bands of frequencies to the noise cancellation sound generators, they also had to apply different shifts, and different amplitudes, depending on the location of the noise source and the eardrums. Yes, I can see why they passed on that one. The Professor's problem lies somewhere between the one I tackled and what NASA tried. His advantage lies in the fact that he can place his noise cancellation speakers relatively close to the noise source. That helps a lot, in that the wavefronts from the two sources can radiate outwards from a single point (almost) and be cancelled no matter where the receiver is located. I suspect one of the reasons he can only attain cancellation at the high end (the whine) is due to the poor low frequency efficiency of the speakers.

--
If I didn't have absolutely NOTHING to do, I wouldn't be here.

Toilets by Anonymous Coward · 2004-03-16 03:00 · Score: 0

They should develop such a sound canceling system for around toilet seats.

Pippin

Screw CPU Fans... by H8X55 · 2004-03-16 03:49 · Score: 1

Screw CPU fans... Are they doing anything for SCSII drives? My wife won't let me bring my Dell PowerEdge into the bedroom because it's too loud.

That sounds sick. But it's true! Something about it being too noisy for her to get to sleep or something.

Engineering by bluGill · 2004-03-16 03:54 · Score: 1

Engineers have known for a long time they can design to lessen sound. However everything is a compromise, and they haven't figured out how to design for less sound without lowering the overall efficiency of the rest of the design. Though sound is a form of energy that they don't want, it isn't a big factor, while the obvious ways to reduce sound level end up lowering other efficiencies as well.

I have not studied the Mitsubishi design so I'm not qualified to comment on the particulars of that one. There is no theoretical reason when the lower sound levels are not a by-product of a more efficient blade shape.

Thin clients like SunRay by markroth8 · 2004-03-16 04:18 · Score: 1

Of course especially in an office environment you could always replace your noisy computers with thin clients like SunRays. It's amazing what a difference a quiet office makes.

How about this ? ... by polyp2000 · 2004-03-16 04:30 · Score: 1

Im thinking ... something like this might work though...

sound-bug (off think-geek) attached to inside of PC case (makes whole case a speaker)
couple of strategically placed condenser mic's (ala 80's tape-recorder) and a nifty phase inverting circuit between the two...

nick ...

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Electronic Music Made Using Linux http://soundcloud.com/polyp

Done a while ago in high end cars... by sameyeam · 2004-03-16 05:15 · Score: 1

I remember seeing a show about this being done in a high end car a few years ago (not sure who it was)...anyway, it was really sucessful and the car was v.quiet. Then they went on to do further testing only to find that people didn't really like it. Instead of ripping out the system they came up with the novel solution of some kind of sampled engine sound played through the car's audio system. I don't know whether the car ever made it to production.

Re:I should have patented it...Arthur Clarke by Anonymous Coward · 2004-03-16 05:19 · Score: 0

It was one of the "Tales From the White Hart", a Harry Purvis yarn, but I cannot remember the title of the story.

The whine by TamMan2000 · 2004-03-16 05:30 · Score: 1

The whine of a fan is caused by the periodic interaction of wakes, and bow waves from rotating blades with stationary objects (you hear this frequency and it's higher harmonics), the only way to get rid of this whine would be to have the fan not rotating (at which point it is no longer technically a fan).

You are thinking of the whine from the bearings, which is almost silent when compaired to the rotor-stator interaction noise.

I used to work in the computational acoustics group at Pratt & Whitney aircraft engines...

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"I'll have a Guinness, no wait, make that a Coors Light" -Grad student I work with, who shall remain anonymous...

That's HB to us UK residents... by TheScienceKid · 2004-03-16 06:13 · Score: 1

... you beowulf cluster of insensitive clods in soviet russia!

Noise cancelling case - revisited by peel · 2004-03-16 06:16 · Score: 1

I had suggested this idea long ago, and posted about it here. I was subsequently shot down. Although there were a few reasons for it not being doable based in science, I can only assume the main reason it didn't go over well was because of the very high gramatical standard that the readers of slashdot hold themselves and others to. -peel

Re:Noise cancelling case - revisited by paroneayea · 2004-03-16 17:01 · Score: 1

I had suggested this idea long ago, and posted about it here. I was subsequently shot down.
You got modded up pretty well, and your responses don't seem to be trashing you. Nobody's humping your leg, but I don't see you being shot down at all.

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http://mediagoblin.org/

Another important point: by Kiyooka · 2004-03-16 07:16 · Score: 1

many car manufacturers *want* you to hear the engine noise. They actually have "sound engineers" that listen to car engines, and make recommendations on how a car should sound (engine sound is an important aspect of marketing a car).

Large trucks, mustangs and generally most other cars that are usually bought for image's sakes have sound engineers. Having a quiet engine wouldn't match the cocky arrogant attitude these cars are trying to sell (apologies to owners of these cars).

I wouldn't expect quiet engines from these cars because they wouldn't do it even if they could.

NOTE TO STUPID FUCKING CLUELESS MODS by Anonymous Coward · 2004-03-16 13:29 · Score: 0

FUCK YOU ASSHATS!!! The above poast was funny as the more clueful moderators have beaten into your thick skulls you fuckers. That is why even though it was modded troll an overrated, it got modded up as funny more. Maybe you should learn something about humour. It really enriches one's life. Fucking dorks. I wonder how many mods modded it down just because T4D posted it?

What, exactly, are you doing with that machine? by Ayanami+Rei · 2004-03-16 17:39 · Score: 1

I've found that a hard drive with 8MB of cache, and a system with 512MB of RAM (all of which ends up as buffer cache) provides more than enough bandwidth for any application that I can use in my humble abode.

Writing to it over NFS/samba is not nearly as fast as local disk, but I use it to primarily to source common data and generally act as a connectivity applicance, not as a data warehouse.

I assume you have an inverted situation?

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THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON

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