Slashdot Mirror
BYU Project to Silence Computer Fans
phunster writes "The New York Times has an article about Scott D. Sommerfeldt and his students at BYU who have created a noise suppression system for computer fans (drop of human blood required to read article). The technology is not new, he uses out of phase sound to substantially cancel out the sound of the fan. What is interesting is his implementation of the technique. While other systems place a microphone and speakers in the center of a room, he places four miniature speakers and microphones around the noise source itself. His results are promising."
BYU Project to Silence Computer Fans
We as /. computer fans have been discriminated for so long, that
you'd think that we, as computer enthousiasts, have had quite enough....
An NOW, these people that have been bullying us all along have invented a system that makes us keep our mouths shut... Just great...
Pills... must... take... pills...
Support a Europe-related section on Slashdot!
We've seen this before here.
A love beyond compare...
If the fans inside your CPU are silent you wouldn't notice if one failed, my machine is fairly quiet but i would notice if it booted without the CPU or PSU fan running.
Snowden and Manning are heroes.
Not when you use this
Why wasn't this posted in the Censorship section?
Corporations try to silence some kid's website, Michael is falling over himself to denounce it. Corporations try to silence fans, and where is YRO? Not reporting on this, that's for certain. A clear double standard. Disgusting.
Apart from the discomfort of wearing headphones over long periods, the noise-reduction works well in office environments. Cuts out more than just noisy PCs: also airco, neighbours, and fire sirens.
Sig for sale or rent. One previous user. Inquire within.
This would be well worth it on 90mm tornados. Its pretty shitty having 4 of them right beside your bed trying to sleep while your linux e-penis uptime grows every night ;)
I don't think this industry has come remotely close to making a fan that works. It's sad when people need tubes running to the bathroom just to keep the GPU or CPU cool.
If you create a fan that doesn't need water and guarantees performance of a water cooler, I think it'd be a hit. I have never the gotten blue screen of death from a noisy fan. Look on any forum, people are not complaining about noise. People are whining about overheating...
Blood Donation
I don't know as much about noise cancellation as I would like, but I understand most of the concepts. Although the method described in the article certainly is very cool, I wonder if they couldn't get better results by redesigning the fan. It seems that the fan generates too much random noise. Is it possible to make a fan that has a more predictable noise source? It could even be a fan that is way noisier before noise cancellation...
Another thought on this is that you really shouldn't consider the fan alone. The G5 has a beautiful interior with a ton of fans. Its not terribly loud, however, because the airflow is well designed.
Now if they could just silence the kids that come to my house to tell me about Joseph Smith.
'Same speed C but faster'
Personally its them damn harddisks that piss me off.
If only someone could suppress the disk noise..
http://www.nytimes.com/2004/05/27/technology/circu its/27next.html?ex=1086235200&en=8355c13a3b4a8afa& ei=5062&source=GOOGLE
Yeah, this is much simpler than just making the fans quiet in the first place, right?
Wonderful. "Look, instead of paying an extra 50 cents for a higher quality quiet fan, you can use cheap fans and spend $25.00 in additional parts to make the computer quiet!"
*sigh*
And how much electricity does this suck up, exactly?
Musicians would care
So would home theater machines
Listening to music on a PC would mean lower required volume
How about being to sleep with a PC on 24/7?
GPL Deconstructed
For a second, I thought that BYU was going to hire big, burly henchmen to "take care" of us Slashdotters...
The perfect sig is a lot like silence, only louder
Get a computer without a fan. I've had my Apple G4 Cube for a few years now, only now really showing its age and completely silent. Well, except for hard disk access. Of course you can't get them anymore, and Apple's new G5s have 4 or 5 fans in them... So don't think this is just some sort of fanboy rant, I honestly think that good design can get around the need for fans.
Yup...
...would kill for this.
I am forced to conclude you are the master of the obvious. May others take heed of your wisdom.
Will the same technology also work on my girlfriend? She is like one of those movies that is just better on mute.
Evolution or ID?
This is bad. The noise from the fans on my machines are the only things that drown out the voices in my head... '...Kill...Userssssss...'
I'm just bothered by the noise from my computer. There are ways I can ignore it, with headphones and such, but I don't always feel like wearing headphones. Idealy, the computer would just be silent.
drop of human blood required to read article
Does it have to be mine?
"Hey Bob, come here, I've got something cool to show you. Oh, and bring a thumbtack..."
Yea, I've been using this technology for a long time; I just crank up my radio till I don't hear my computer. Unless Britney Spears comes up, then I prefer the soothing noise of my computer.
We are the people our parents warned us about.
While other systems place a microphone and speakers in the center of a room, he places four miniature speakers and microphones around the noise source itself.
Will the wife version require something worn around the next and will it have a remote control?...
"All great things are simple & expressed in a single word: freedom, justice, honor, duty, mercy, hope." --Churchill
I remember an old episode of Beyond 2000 (http://www.techtv.com/beyond2000/ , but the old Australian version) where they showed an anti-noise system that would fit into a car's exhaust system. Microphones would pick up the noise from the exhaust manifold, a DSP would generate the appropriate "Anti-noise" then subwoofers would inject the Anti-noise sound into a specially designed muffler. The demonstration would drive a big V8 Holden muscle car around, clicking the noise reduction in and out. Without it sounded like, well, a muscle car. With noise cancellation it sounded like a Rolls Royce, that is, you didn't really hear the exhaust at all, just tires rolling on pavement and wind. Really cool, but probably too expensive to implement in most consumer vehicles :(
My Other Computer Is A Data General Nova III.
The fan noise from a serious computer has long been the single bigegst noise problem in the modern digital recording studio. It used to be the most popular solution was putting your tower in a closet somewhere with long extension cords for the keyboard, mouse, and whatever else. I've seen this used in several studios.
I think I speak for audio engineers everywhere when I say HALLELUJAH! This is a seriously practical and useful invention, hopefully it will be affordable!
They will never stop until somebody makes the
"It's going to be a matter of what the consumer will be willing to pay for a quiet computer," he said.
Are these guys not familliar with items like this? Somehow I don't see these fans costing that much.
I just unplug all my computer's fans. Now my computer doesn't make any noise.
At least my fiancee is happy about that.
I just put 2 small extra fans into my p4 1.8 gzh machine (I went and got a nvidia fx chip and was worried about heat). It sounds like a friggin hair dryer. Although I've managed to tuen it out. I notice it when i turn it one and apaprenlty everyone in my 3 floor house notices the noise of this one computer.
"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy."
An interesting project, but it certainly seems like a Rube Goldberg (Heath Robinson for UK readers) way to go about it.
The Mac G5 approaches this problem by using lots of big, slow-turning fans. It's probably expensive, but I doubt that it's as expensive as active noise cancellation. And Apple did a very good job. The Mac G5 is not silent, but in normal operation it is quieter than any machine I've used since the fanless 1984 Mac and the Apple ][.
"How to Do Nothing," kids activities, back in print!
So your wife can't hear you on the computer as she sleeps while you slashdot.
yay mormons. ;-)
very cool - but the holy grail is to make a _fanless_ computer. fans are moving parts. moving parts are bad.
if you just make the loud moving parts silent, then you are only removing the symptoms - but the real problem is still there: moving parts prone to failure.
its a good idea until they get heat pipes to work with 100W processors.
I found it amusing to have an add for noise *generators* come up along with the noise reduction article.
[yes, I know it's not quite the same thing]
Or suppose your computer is in your bedroom, and you leave it on overnight. Wouldn't it be nice if it were quieter? Even the fan and hard drive in my DTV Tivo are annoying at night -- and it's much quieter than a full blown PC.
the computational power needed is roughly equivalent to one computer.
..........FULL STOP.
Why don't case manufacturers do away with the power supply and integrate a UPS into the case? Rather than have AC -> UPS (which converts to DC to charge batteries) -> AC -> Power supply (which converts to DC) why not cut out all the wasteful conversions? I could even see having room in the battery portion so you could upgrade to additional "plug in" batteries. Any thoughts?
I Am My Own Worst Enemy
welcome this new chance to write this annoyingly-repeated joke once again.
1995: My hard disk is just too darned loud!!
2000: I can't stand the hum of the case fan!!
2005: That LED is hurting my ears!
<insert witty linux comment here>
I'm with you. I was wondering why this wasn't in "YRO". That's where we'd usually find the free (as in speech, not beer) flamefest and troll-con, right?
Welcome to the Panopticon. Used to be a prison, now it's your home.
I suggested this awhile ago for another article on silent computing. It got shot down quite handily, mainly because I can't speel verry whell. Anyway the people that did respond with things other than spelling mistakes had good insight into this. It seems this guy has come up with workarounds for problems they noted. -peel
To Quiet a Whirring Computer, Fight Noise With Noise
By ANNE EISENBERG
Published: May 27, 2004
THE constant drone of a computer cooling fan can be annoying. But a professor at Brigham Young University has taken an unusual step to mute this noise: more noise, produced in just the right quantities from tiny loudspeakers that surround the fan.
"We make anti-noise," said Scott D. Sommerfeldt, a physicist who created a noise suppression system with his students. It is the latest example of a technology called active noise reduction, or noise cancellation, well known from its use in headphones designed to block out the low rumble of jet engines.
The sound waves engineered by Dr. Sommerfeldt are out of phase with sound waves from the fan and thus they cancel each other out, substantially reducing fan noise.
Dr. Sommerfeldt's system has four miniature speakers and four even tinier microphones set in a ring around the computer fan. The microphones and other sensors detect the noise of the fan blades and, with the help of digital signal processing and algorithms, radiate opposing tones from the speakers. The whole system can be tucked into the same space that a conventional computer cooling fan would occupy.
Noise-cancellation technology has been in development for more than 50 years, Dr. Sommerfeldt said. In typical headphones, microphones in the headset detect noise; the speakers in the earcups counter with anti-noise.
Dr. Sommerfeldt's target was not the roar of aircraft, but the hum of office machinery. To counter this noise, some active noise reduction systems place microphones and related gear in the middle of a room to calculate the amount of cancellation needed.
But Dr. Sommerfeldt wanted to put the system within the computer casing itself so that it might one day become a built-in feature of personal computers.
Trying to cancel noise from within the computer turned out to be tricky, though. "You are asking for trouble if you place the mikes right next to the fan," he said. While it may be possible to reduce the sound substantially at the microphone, he said, the noise level could increase farther away, where someone might be sitting.
To solve the problem, Dr. Sommerfeldt built an aluminum enclosure that mimicked a typical computer chassis and put a standard cooling fan within. He and his students placed microphones and speakers around the fan, analyzing the nature of the sounds they would have to suppress and modeling systems to counter this sound.
"The fan is not an easy source of noise to control," said Gerald C. Lauchle, a professor of acoustics at Pennsylvania State University and a colleague of Dr. Sommerfeldt. "Many interacting mechanisms create the noise."
The specific sounds Dr. Sommerfeldt decided to counter were those made by the blades of the fan as they rotate and push air past obstructions like fan supports. The pushing is periodic, dictated by the number and speed of the blades.
In the experiments, sensors mounted near the blades of the fan recorded the motion, and the information was fed to the digital signal processor along with the data from the microphones that were monitoring the overall noise. Then algorithms developed by the group adjusted the amount of canceling sound waves sent to the speakers so that the basic tone of the blades could be suppressed, as well as overtones or harmonics of the basic tone.
"The basic tone is distinct," Dr. Sommerfeldt said. "It sounds like one you could hear if you hit a piano key."
To find the pattern that worked best, the experimenters set up systems with one, two, three and four speakers. "We went with smaller loudspeakers and more of them," Dr. Sommerfeldt said. "The best configuration turned out to be four speakers spaced around the fan."
The group measured the reduction in sound at the fan and at various points at a distance, said Brian B. Monson, a graduate student of Dr. Sommerfeldt.
The experiments used two fan sizes, with b
Ohana means family. Family means nobody gets left behind or forgotten.
The grind and vibrations of your harddrive is also a significant factor in computer noise(though with a good drive it becomes secondary to fans). I've set my own computer at a slight angle(the back on a pillow) to reduce this noise, even though it increases my chances of HD failure.
I use my good ol' AK-47 to silence them damn computer-lovin' freaks.
I passed the Turing test.
This space for rent. Call 1-800-STEAK4U
If they do manage to silence us, what then?
At least I still have other hobbies like...er...um...dammit!
In some instances it's not just the noise from the fan but the vibrations fan induces in surrounding objects.
For example I built a media-center OC using a Silverstone SST-LC03-B case, replaced the 60mm case fan with a Vantec "Stealth" fan, used a Zallman silent power supply and a Zallman copper/alimunum heatsink/fan, with the fan speed controller on it's quietest setting. In an office environment, sitting on the cases' shipping box while being tested and set up, the machine was virtually silent - I had to hold my ear next to it to hear anything.
But as soon as I put it in my oak entertainment wall-unit, the wood resonated at the case fan's frequency and it was unbearable. The only solution was to disconnect the case fan entirely.
Barring cost, why not use the same technique as those filterless air purifiers. They produce directional air flow, which I have always assumed the velocity of the air was a function of the amount of electricity used in the system.
Lecter: Well, Clarice, have the fans stopped screaming?
The makers of speakers and microphones were too busy high-fiving each other to comment.
As others have pointed out, quieting a single fan is only a small part of the battle. Unless that's the only moving part in your computer it seems like a bad idea to need a separate antinoise system for every noise source.
Instead, I would elect to design the case not only for airflow but also for noise "flow". I'd spray panels with some kind of dense material - automotive undercoat might work fine, or barring that, spray-on bedliner. Or, I would use an adhesive panel such as dynamat. This has the significant advantage of being inexpensive. I would have one air inlet and one outlet, and only one of each, and I'd place my sensors and audio elements there. I'd also use baffles coated with a highly efficient sound-damping material which could be more expensive than the case coating.
But, there is an even better way to do this, which is to use heat pipes to carry the system's heat to a large sink on the outside of the case. Or alternatively, use an external water cooling system. I was originally planning to do water cooling inside my PC (as there should be ample room in a 4U rack case) but I am now planning to make it external so I can put it behind some shit for noise purposes.
With all this ranting said, when the technology gets cheaper and we can embed it into disposable fans, this very approach will be practical. Since it usually requires a DSP and some not necessarily inexpensive speaker units, that's a little ways off. I think it would be better to work on ways of not generating that noise than to cancel it, which is by its nature a wasteful process.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Also from that part of the country, SCOX has filed a lawsuit against all computer fans who use Linux, in an effort to silence them.
I'd be happier if I could cancel the noise coming from the other people on my bus. There are days where I get off the bus ready to kill something.
Eliminates inane chatter! Loud cellphone talkers banished! Never hear the high-frequency noise of other people's headphones! Buy now, only $29.95!
I would sprain my wrist trying to get my wallet out to pay for it fast enough.
HBH"Smart is sexy." -- D. Scully ("War of the Coprophages")
Now they've just got to figure out a way to strap one of those noise-reducing speakers to the missionaries that BYU keeps churning out.
To take care of nosy nerds, they send ditzy chaste-yet-teasing BYU coeds. Guaranteed to frustrate and/or bore you to death within hours, unless you're a RM (returned Mormon missionary) in which case you'll end up married to them within two days.
Either way, problem solved.
"We have to go forth and crush every world view that doesn't believe in tolerance and free speech." - David Brin
I quieted the fan in my power supply by jamming a metal fork into it. As soon as the blades of the fan came into solid contact with the tines of the fork, the fan stopped spinning and my computer has been much quieter ever since.
About the same time, I noticed that my computer began actng strngly though so maybe ths wsnt teh bsts srlstuion aftr ahl....?
** NO CARRIER
"A revolution without dancing is... a revolution not worth having"
BYU Project to Silence Computer Fans
For now at least. I'll collect later.
Caution on the 400SC with SATA: it won't boot from 3rd party IDE cards (such as you'd use for mirroring).
Maybe we should look at the fan design first. When Brushless-DC fans were first introduced in the early 1980's I evaluated most of the major brands. Blade shape and contour were major contributors to noise, but by far the worst was mounting the fan up against the panel wall with holes or a grill. Running slow also reduces noise. One company's blade design removed the high pitch wind noise and just left a low pitch rumble that sounded quieter than it was. Centrifugal "squirrel-cage" fans were much quieter than axial fans. Sleeve bearings were a little quieter than ball bearings, but had a much shorter life and will "freeze-up" once the oil dissipates. (I actually had this happen to my old computer.)Ball bearings get louder over time, but you'll replace your computer before then.
Power supplies can reduce airflow requirements considerably by better heatsinks and/or using the chassis for moving the heat away from the hot components. Once the real design issues are tackled, the bell-and-whistles approach could then be used to further reduce sound levels as necessary.
Dell mounts one fan deep inside the computer and the PS fan is quiet but near a wall. Six weeks ago I bought a Systemax and a Dell computer. Systemax sounded normally obnoxiously loud. Dell was so quiet, I thought it was not working, so I opened it to see if I could tell what was wrong. I was fooled by the sudden start of noise and then quiet.
The solution is not more noise. I've heard rumours of evil things happening to your brain when the noise coming in one ear is slightly offset (time wise) from the noise in the other ear.
.7 Sonne, 130 CFM fan that is vented from all the cases (5 of them @ 19x19.5x7)
Between the 6-8 desktops and 2 laptops floating around my desk at any time, my noise quotient was pretty damn bad, even when I took most of them down to the bare minimums of fan noise. Yes, I could have replaced all my fans with nice quiet ones, or modded the cases for noise reduction, but then I'd have to do that with every case, every time I changed up.
The solution? I scored a cheap-ass enclosed LAN rack, got some cheap-ass wood cut for me at the store, and build my own LAN cases. The only fan in my entire 6'4" rack is a
My systems have never been cooler, the noise is so freakishly quiet that I'm still getting used to it, I've got more flexibility than I ever did, and with everything KVM'd, I've got a cleaner desk. Total cost? Maybe $200 CDN [insert "so that's $.05 US?" joke here]. And, on the bright side, with so much extra space in my cases, my mod list is getting bigger and bigger with all the nifty things I can do.
Sure, noise cancellation works in the short term, but 8 hours a day or more? I'd be worried that some slight imbalance somewhere might screw with my brain or break my ears.
Plus, my kick-ass blacklighted rack with piles of blinkenlichten is MUCH cooler than some wussy lil speakers.
If I knew the wedgies I gave you back in 6th grade would have resulted in this . . . I might have taken a moments pause.
Conservation of energy?
:)
Or does the air just get hotter? (thereby making the fan rather pointless)
Seems like some physical law is getting violated somewhere
Does the silencer require a cooling fan of its own?
Have you read my blog lately?
I work in a computer music and acoustics research lab and we're always after a quieter PC. We've considered a solutions like this, but we've decided it wouldn't really be necessary for long. Here's why.
Among the many reasons for having a hard drive in every computer, two of the big ones were the Microsoft vision statement, and the fact that the network was much slower than disk. The latter is no longer the case.
The fact that network is now faster than local disk is a MAJOR development.
We've experimented with RedHat 9 with nfs root on older hardware with no disk and no fans, with 100Mb bootable NICs. We found to our surprise that they ran faster than with standard (non UDMA) ide. So, we're trying it now with newer hardware and gigabit, and some BIG heatsinks. So far, so good. We can optimize the central storage for speed, and the systems do, in fact, run noticeably faster in most cases, in addition to being nearly* silent.
We hadn't counted on the added bonuses, but there are many. We can change an entire system disk by moving dirs, reexporting, and booting the machine up. Poof, new system. We can install and uninstall packages on machines while they're off! We no longer have two or three extra gigs on each machine, all our nfsroots are from a single physical filesystem (so far) so they all have the same amount of free space, much more efficient! And if a machine offends you, you can yank the plug out. No local fsck!
*Note that the machine is never truly silent. Without any fans or disks, you can still hear a certain noise that sounds like it's happening when the disk used to seek. It's the toroids in the power supply! The network traffic causes HF noise in the power lines, which is filtered in the power supply and causes the chokes to vibrate slightly. The noise is very low, it would easily be drowned out by the quietest of fans, but in a totally silent room with no other PC sound, it's quite audible. There is also some low and infrequent clicking while the machine is warming up and cooling down, due to the thermal expansion of the heat sinks. This doesn't happen during use, when the temperature is more or less constant.
I'm supposed to document all this and I've been lazy, so if you want the rundown on booting redhat 9 without a hard drive, write to me and I'll finish the page and send you the link.
How can I send the blood? All I seem to get is a smudgy monitor.
I don't need a signature.
Obviously you never studied acoustics.
Noise-cancellation as implemented by these systems relies on matching an equal in amplitude, but opposite in polarity, waveform, to the incoming acoustic wave. By combining a compression wherever there's a rarefaction and a rarefaction wherever there's a compression, you wind up with blissful silence. However, the nature of these systems dictates that the interference only happens at specific places; where the waveforms match exactly. If you could place your cancelling radiator at the same location in space as the unwanted radiator, with the exact same radiation characteristics, it would be great, but you can't. Instead, you get cancellations at certain locations and intensification of the noise at other locations.
Basically, due to acoustics, getting closer to the noise won't do you as much good as getting closer to the receiver of the noise. This is why NR headphones work great, and aren't hard to do, but NR for open environments is hard to do and doesn't work very well. No matter what you do, unless you can colocate the cancelling radiator, you will always make some parts of the freespace environment worse.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
As well as silencing your computer fans, you can also silence your hard drive. Guaranteed you won't hear the sound of a whining hard drive ever again, or in fact any noise from your hard drive at all. One step closer to an all-silent computer system.
:-)
already have IP rights to that idea?
That which does not kill her only prolongs my agony.
Unite!!!
They may try to silence us, but they will fail.
We will not go quietly into that dark night, we will go kicking and screaming...
<sound of muffled voice whispering, patiently explaining>
oh, well, carry on then...
Why bother with all this technology when you can reduce noise to a tremendous degree by using a nice quiet Nexus power supply, Nexus CPU fan, and quiet fluid bearing drive hard disk?
Self awareness - try it!
Your analogy is flawed. Suppressing a light bulb is passive noise cancellation. This is equivalent to draping the fan in a sound-deadening material.
Active noise cancellation is different, and your statement is not usually true for active cancellation; ANC usually works better when you get the cancellation radiator closer to the receiver, as opposed to the noise.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
If it's revolutionary to do this by measuring noise at the source rather than from the center of the goddamn room, well, I guess they should've looked at the noise-cancelling-headphones industry, which have been doing this for years. What kind of dumbass measures the noise away from the source and then tries to compensate for all the reflections and distortions that could occur in the path between the source and the reciever?
Software piracy is victimless theft.
Yeah but if you have a whole room full of lights, its easier just to shoot them all out with a bb gun.
Well, yeah. That is what I was wondering.
Sure, this works if you sample your engine noise and want a quiet passenger compartment. But does one really want to create standing waves around a cooling fan?
I thought it was, "BYU project to silence Cougar fans." But then I realized that the football team isn't a new project, so I knew I was mistaken.
Lasers Controlled Games!
I have tried the noise reduction headphones, and I can hear the cancellation noise just as loud as the other noise. I am guessing this affects other people too. If noise cancellation is an issue, why not run another fan exactly out of phase, rather than try to generate a noise that is the "opposite"? I think you'd have better results if it was a real fan (despite that the power drain would be 2x).
stuff |
"Exidy Sorceror is pure magic!"
Wow. I remember that. That was the first computer that my dad owned. He used it to write the first edition of his book. I remember playing the old Scott Adams adventures on it when I was like 8 years old (30 now)
Technoli
It's never been clear to me how this is supposed to work from the standpoint of conservation of energy (I've read several dissertations on the subject). Is the canceling source (the anti-source) supposed to dissipate the energy in the traveling sound pressure wave (a-la active damper), thereby stopping the sound from propagating, or does the source provide short-term energy storage to reshape the spacial sound pressure field distribution, or is there some non-linear effect that redistributes the sound spectrally (translating peaked spectra to lower-level flat spectra -- a sound whitener)?
This would be great for projectors. My home theater projector's fans, while quiet at somewhere around 30db, can be annoying at times. I'd love to have active noise cancellation, assuming it didn't affect the sound coming out of my speakers.
get nemulator
We must fight the oppressive powers and not let our fans be silenced! It is our duty to protect Fans' Freedom of Speach!
You can mod your friends, you can mod your nose, but you can't mod your friend's nose.
How about being to sleep with a PC on 24/7?
Some people actually like the noise from their fans.
I know that I can't sleep unless my computer is on. I need the white noise produced by my fans in order to sleep. In fact, even if I'm not trying to sleep, I can't stand being in my room if the computer's off (which it rarely is, unless there's a power outage) because I'm so used to the white noise from its fans.
I support the Center for Consumer Freedom
Why can't they replace the bearings with magnets? And shape the fan blades to avoid the wasteful noise entirely, at least in the audible band?
--
make install -not war
I recall one theory regarding ANC that looked at the canceling source as a type of acoustic impedance modifier. Pointing the canceling source directly at the sound source would cause a standing wave between the two, but would transform the acoustic impedance into the rest of the room such as to make the combined source inefficient in radiating (preventing the sound pressure wave from propagating past the impedance transition presented by the active source). The "active damper" model.
I bought a few fans from SilenX and I'll tell you they are the quietest fans I have used yet. I usually stuck with the Panaflo's but I am definitely a convert. (not to sound like a salesman).
-----
Web Hosting @ HostForADollar.com
This isn't my field of study, but why do you suppose these guys want to put the microphones so close to the fan? The feedback into your control system is going to come from those microphones, so wouldn't you want to put them out near where someone will be? It seems to me that otherwise you'll do a great job making the area close to the fan quiet, but it won't help you anywhere else.
I'm glad someone has made the appropriate logical connection, from applying this technology to some giant industrial machine, to applying it to individual computer parts. I was thinking about it last week, but then I didn't _do_ anything about it. It seems so much simpler, in the long run; instead of silent components, just make silence.
I do wonder, however, whether a defective implementation would _increase_ the noise level. Best to be careful, and you'd better be able to disconnect the silencer when it becomes a shrieker.
HSF and exhaust fan running full blast, plus a 24" box fan blowing into the case to keep the drives cool. actually helps me sleep.. if the box fan is off, i find it harder to sleep.
i'm not everyone though.
Couldn't they use instead of a fan an "ionic breeze" system like the one the sharper image uses in its air purifiers?
I've been thinking of those for a long time cause they are really silent and they do move air. But I really do not know if they can work inside a computer cage.
~~~Please pass the salt, I hate unsalted MD5s
How about a fan with more blades, for example 20 or 30 smaller blades?
Using a lower rpm, the fan with more blades could blow the same amount of air as a normal fan, but run MUCH quiter.
IANAE so I am wondering if using out of phase noise cancelling approaches actually reduces the SPL on your ears.... or does it just drown out the original noise with another noise that renders them virtually silent.
Keep the Classic Slashdot.
Not knowing much about acoustics, but having followed this discussion, I would speculate that the goal of putting 4 microphones next to the sound source is to surround the sound sound relatively equally and approximate colocation. Imagine a hundred tiny microphones forming a circle around the sound source. Any boost to the original sound given off by a given microphone should be cancelled out by a differant one on the circle. Also, no microphone would be terribly powerful, so the boost wouldn't be that great. The approximation would be of a single sound source in the center of the microphones - I think.
Well, to REALLY get the horse before the cart I'd hope that SOMEONE would focus on building computers WITHOUT FANS. Apple has done this, others have. Heat sinks and convection can go a long way, especially when the computers we are used to these days are vertically oriented to begin with. Put the hot stuff at the bottom of a case with a tube over them that allows the hot air to by sucked up to a vent at the top. A slow fan could kick in to assist if things started to overheat. There are fans that operate at a few undred RPM and are almost silent but still move a good amount of air.
Maybe there needs to be a new version of computer hobbiest called "Underclockers" who take a 3G processor designed to fry eggs and runs it at 700Mhz without a fan. Meanwhile I'm sitting here browsing Slashdot with a 3D mega triangle video card with its own fan and 64M of memory. Does anyone make a video card these days that is both (1) really fast, and (2) doesn't have all the horsepower and programming to do 3D rendering? Hardly. I don't MIND the 3D capabilities per-se, but I've known many people already that have had to replace their video cards after they burn out, and often I think the culprit here is accumulation of dust in and around the video cards fan. I get a BIT of dust on my case fan when I open it up from time to time, but the tiny fan on the video card is almost always close to being clogged with what they used to call "dust bunnies". Eventually some of these apparently accumulate to the point where the fan just ejects them onto whatever component is below. Some of these case designs go beyond what I'd call "bad" to downright incompetent. Or could it be deliberate planned obsolescence?
I'm still hanging onto my old Dells, some of which, as mentioned above are designed to be quiet (even with a fan). I'll get my wallet out again when the systems appear to be designed to last and run quietly. My stereo equipment puts out some heat as does my TV and THEY don't have fans. When the most complex thing I use my computer for makes it act a whole lot like a stereo system or TV you have to ask where did we go wrong here. (I know the answer, but I'll get labeled a troll if I say it, so I'll leave it as an exercise for the reader).
Clarice Starling: [tears begin forming in her eyes] And one morning, I just ran away.
Hannibal Lecter: No "just", Clarice. What set you off? You started at what time?
Clarice Starling: Early, still dark.
Hannibal Lecter: Then something woke you, didn't it? Was it a dream? What was it?
Clarice Starling: I heard a strange noise.
Hannibal Lecter: What was it?
Clarice Starling: It was - screaming. Some kind of screaming, like a child's voice.
Hannibal Lecter: What did you do?
Clarice Starling: I went downstairs, outside. I crept up into the barn. I was so scared to look inside, but I had to.
Hannibal Lecter: And what did you see, Clarice? What did you see?
Clarice Starling: Fans. The fans were screaming.
Hannibal Lecter: They were suppressing the CPU fans?
Clarice Starling: And they were screaming.
Hannibal Lecter: And you ran away?
Clarice Starling: No. First I tried to free them. I-I opened the gate to their pen, but they wouldn't run. They just stood there, confused. They wouldn't run.
Hannibal Lecter: But you could and you did, didn't you?
Clarice Starling: Yes. I took one fan, and I ran away as fast as I could.
Hannibal Lecter: Where were you going, Clarice?
Clarice Starling: I don't know. I didn't have any food, any water and it wasvery cold, very cold. I thought, I thought if I could save just one, but - he was so heavy. So heavy. I didn't get more than a few miles when the sheriff's car picked me up. The rancher was so angry he sent me to live at the Mormon orphanage in Provo. I never saw the ranch again.
Hannibal Lecter: What became of your fan, Clarice?
Clarice Starling: They killed him.
It's all fun and games until someone loses the key to the handcuffs.
Some do, but BYU is a little bit of a different case, as they are a Private U, not state. They do run filters on their own net services.
As for the protestor above the bottom pic, that's nothing, you should see the amazing things people say that the LDS church does. Walking in SLC during the conference time is amazing, I've been charged with being everything form a murderer to the devil incarnate for being a member of the LDS church.
Actually, two things wrong.
;-) (Just kidding! JUST KIDDING! Yay for school rivalaries.)
You didn't read the bottom screen carefully. It specifically states that you can access the blocked web page through a different computer in a different building. BYU has heavy filters on all of their public access kiosks (ones that anybody can walk up to and get on... there's a lot of them on campus) and it's actually pretty smart to have that.
Second thing, the filters they used to run have actually been removed and modified. Living on campus (here at BYU), I had to deal with an annoyance every once in awhile, but if you call up the office of IT, they generally will review the page and put it up if they feel it is within the bounds. With that said, all blocks have been removed since I lived on campus (about a month ago I moved off campus).
Third, I forgive you. You're from the U... that's always telling.
I re-soldered the take-offs for the fan power to the 5V leads (red vs. yellow). The machine stays adequately cool with the (3) fans running at the lower voltage, and I can't hear them at all.
On another note, the hard drive was causing a lot of noise during access. I found that there were two reasons for this: one, the drive was very fragmented from having (ahem) large files constantly copied on to it and then deleted, and the NNTP client was contributing significantly to the fragmentation. Here's what I did:
(1) Installed an old 6GB hard drive just for the NNTP message headers.
(2) Defragmented the main HD with O&O and left it resident.
(3) Established a RAM disk for the browser cache while I was at it.
Now the machine runs as near silent as I can imagine, and much faster.
Incidentally, I painted it black (including the drive faces and bay inserts) with Krylon Fusion, "The no-prep superbond paint for plastic". I have never been a fan of painted computer cases, but the Krylon product does a great job without actually doing a proper prep and spraying with an expensive two-part paint.
I'm thinking of a ring shaped magnet, in a ring shaped track with sides enclosing the magnet. Like a monorail bent into a ring. If the facing sides of the ring and track are the same polarity, the inner ring will hover. Neodymium magnets, like in mobile headphones, have enough force:weight to float the suspended ring and plenty of plastic blades attached within, and shaping the ring can allow magnetic pulses to force the ring to spin. Voila! For my next trick, I seal the ring inside the track, balancing the fan disc magnetically inside a split leaving gaps smaller than O2 molecules, sealing a vacuum inside, for no friction in the "bearing" at all.
--
make install -not war
Did they try wrapping the fans in magic underwear?
Tim
Omnia vestra castrorum habetur nobis.
Active lightbulb cancellation would be impossible from what I understand. With sound it works because the sound waves are compressions and expansions of air that make your eardrums wiggle. Output the exact opposite sound wave to counteract the first one, which means that the air is being expanded by one wave, but compressed by the other. The result is no *net* movement of the air, depending of course on your position in relation to the two sound waves.
Light is just photons (which have wavelike properties) hitting your eye. To counteract that, you would have to fire some kind of anti-proton, which doesn't exist. The "anti-light" source would probably have to be in the same place the light source, so that the "anti-protons" come from the same direction.
In a vacuum there's not exactly air to cool the cpu now is there... ;-)
Supplies!
http://www.zalmanusa.com/ (Go to Zalman TNN500A, couldn't get a direct link due to flash menu system)
This thing is a triumph of brute force engineering, but also extreme elegance in design. Basically THE ENTIRE case is made from Aluminium between 5mm and 7mm which is connected using heatpipes to the graphics card and CPU and simply dissipates the heat output passively into the surroundings. You can use the latest parts, the dissipation is rated up to 150W CPU heat output and 50W GPU output. The PSU uses VERY high quality components and is totally fanless. You can get a UPS system built into the bottom as an option as well. I think Athlon64 and Pentium4 CPUs are currently supported.
This idea of using sound to create sound is a no goer in a recording studio where the control room needs to be completely silent and presumably countless scientific and engineering applications. You could have the PC in another room, but this would definetly be prefferable for the majority of users.
Yep, its seriously expensive (not sure, maybe up to GBP1000), but it works flawlessly, looks great, and is ideal for conditions where complete silence is a must, not just noise reduction. Compared to other bits of kit that probably will be sitting in the same area (5000 Vintage Mics or a soundproof room) its a small price to pay really.
His name is my name too!
Libertarianism is rich wolves and poor sheep playing gambler's ruin for dinner.
Sorry CmdrTaco, we've had this news before: Cancelling Out CPU Fan Noise, 16-Mar-2004
"Oh yes, and as for the American Indians with dark skin, if you read the actual text of the Book of Mormon you would know that in the last days they are to be one of the most blessed peoples of earth and that in the days after Christ were among the most righteous on earth."
True, and, in fact, a close examination of the Book of Mormon reveals that some of the most righteous and inspiring people at times were indeed dark skinned (Lamanites): Samuel, King Lamoni and his father and brother, the people of Ammon, the two thousand stripling warriors...etc.
"Creativity is allowing ones self to make mistakes. Art is knowing which ones to keep" - Scott Adams
Mmm... yes, and no.
Point sources radiate differently than spherical membrane surfaces, which is what a hypothetical sphere of radiators would approximate. Fans aren't even point sources, so your radiation pattern is even more different, plus there's the whole impracticality angle in terms of - it's a fan, if you surround it with a sphere of speakers, the air is no longer doing something useful.
But the approximation for a sphere of cone radiators (speakers) isn't the same as the approximation for a single point source.
Acoustics is confusing as hell, even if you've studied it, and it's been a couple years for me, so I might be off.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
The problem I'd see there is that it relies on the radiation pattern of the source being exactly cancellable; I would think that if you have something that radiates in a typical lobed pattern, you'd need a cancelling source that could radiate in an inverse lobe, which is (AFAIK) nonexistent.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
I for one whole-heartedly endorse BYU Coeds :-)
"Creativity is allowing ones self to make mistakes. Art is knowing which ones to keep" - Scott Adams
I'm not certain, to tell the truth; I think that it is possible, but has to do with phase cancellations. However, it only makes sense with a coherent light source; if you have an incoherent light source (like a light bulb) you have basically the same problem as broadband noise suppression, which is very, very hard.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Custom-built quiet PCs. I'm not affiliated with them in any way, I just think it's a good idea and am probably going to buy one.
You can see how our friends in Soviet Russia might be confused by this saying.
I wish people would stop trying to silence computer fans. I can't sleep -without- them. A humming computer lets me know the world is right, and good, and that it's safe to close my eyes.
The article talks about canceling the sound from 'the' fan. Some people have lots of fans in their case. There's the powersupply fan, a possible GPU fan, a possible north bridge fan, and possible fans on the case for extra air flow. Also there's the HD and optical drive making noise. These noises should all be eliminated muffled, pc drone gets on my nerves now and my next pc will different.
You can already make a dead silent pc without sacrificing performance or resorting to this complicated gadget. Get big passive heatsinks for the cpu and gpu. They look like this. It works on regular cps and seems to be a much simpler solution than four sensors four speakers and a signal processing unit.
This guy has lots of hints for reducing noise and that's just the first hit on google.
The fan on my video card died and I didn't notice so I lost the card. It was only a geforceMX but I'm a little bitter.
Fans die. Wether I notice in time isn't imortant to me, it's still a pain.
- Non-whites were "less valiant" in the pre-existence, and so their curse is to live in ignorance and slavery in this life (also taught in the Book of Mormon and D&C)
- It's better that a man kill his adultrous wife to save her by "blood atonement" than to let her die with her sins
- Adam was god the father
- Homosexuality and adultry are sins only surpassed by murder
- The Catholic church is the whore of all the world and the church of Satan (also taught in Book of Momon somewhat)
- Man cannot get into the highest degree of heaven (the "celestial" kingdom) without having multiple wives
- Women can't get into the same place without the permission (and proper handshakes "through the veil") without her husband
Go look for yourself if you don't believe me.The wheel is turning, but the hamster is dead.
The G5 is quite possibly the quietest desktop around, except for maybe their quieter fanless iMacs. Considering how well a G5 works, it's simply amazing how little noise it puts out...
There exists no way of exchanging information without making judgments. --Bene Gesserit Axiom
Who really cares about noisey fans/hard drives. No big deal. They won't wake me up at night like so 15 year old poser in his tricked out Civic with more bass wattage than horsepower.
Stop that noise and I'll buy 10.
I think it's just my fan readings that are off. My computer is dead quiet when that CPU fan is throttled to 50 (i bought all quiet other components). Still, I'd like to run that fan at full RPM for XviD encoding. I can't do that on a hot summer day without throttling it up.
Photos.
Why not just replace with quieter fans.. They have those available now.
Subzerorz
More Articles
"BYU Project to Silence Computer Fans"
Ok, so who else read that and thought some Luddite Mormon Mafia was going around and breaking geeks kneecaps?
And all our yesterdays have lighted fools The way to dusty death. --Will
Or maybe he's deaf? Wouldn't call that lucky..
no taxation without representation!
Because this is supposed to happen in the "near field", a canceler of this type would just have to take into consideration the sound pressure field at the radiator's aperture (for a horn radiator), this is much more difficult if the radiator is omni-directional. That said, it's still not clear to me which paradigm these ANC systems are supposed to operate under.
Thanks, I figured I was wrong but would draw out someone who knew more. I was hoped I was a little more right, but I guess that's how it goes.
I'm always glad to see fellow members on slashdot. :) Last semester, my sister lived pretty close to you (University Villa). I've been in Springville for a year and a half now, and I love it down here. The singles ward is a little bit older than the BYU wards, which is nice. Definitely agree with what you said - while Utah is far from perfect, it is a refreshing change having friends who believe the same things I do.
Anyway, just wanted to say "hi" and I'm glad to see you guys speaking out.
Right, but most unwanted radiators are nowhere near representable as a horn radiator; they are, if not purely omnidirectional, certainly far more omnidirectional than a horn.
You don't happen to have any info on that approach, do you? IEEE paper or something? I'd like to read about it, if you can track down where it was printed.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
Acoustics is probably the branch of engineering I found most counter-intuitive, and I've hit almost all of them at one point or another (elec, mech, aero, chem, materials, even a bit of nuclear). It doesn't work the way you'd think it would, even once you know what's going on. Weird shit, but very interesting - just recommend some background in fluid mechanics/dynamics and differential equations if you're going to try to treat it mathematically.
The best book I know of, if you want to read up, is Fundamentals of Acoustics by Kinsler. It's very much an engineering oriented text, though; if you want a more practical book, track down a guy named John Bracewell. Ask him for his theater sound design textbook; a lot of it is aimed at doing sound design for theatrical productions, but there's some good basics on acoustics and psychoacoustics.
---
Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)