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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...
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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*
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
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?
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..."
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!
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
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.
I use my good ol' AK-47 to silence them damn computer-lovin' freaks.
I passed the Turing test.
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")
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
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.
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.
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.
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Mod me down, you fucking twits. Go ahead. I dare you.
(I read with sigs off.)
already have IP rights to that idea?
That which does not kill her only prolongs my agony.
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!
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
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.
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).