BYU Project to Silence Computer Fans 369
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."
We've seen this story before (Score:4, Interesting)
We've seen this before here [slashdot.org].
Comment removed (Score:5, Interesting)
Re:Okay... (Score:5, Interesting)
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?
Re:Next project... (Score:3, Interesting)
Just politely tell them you aren't interested and they will politely leave. Mormon missionaries are not pushy.
I've practically had to call the cops to get rid of JW's.
Re:Yes, much simpler than.. (Score:3, Interesting)
higher quality, "quiet" fan [directron.com]
Hardly 50 cents. And, I doubt an IC, four mics and four small speakers would cost 25$ in parts.
You can engineer a fan with perfectly balanced blades, great bearings, and eliminate much of the mechanical noise due to vibration or friction. But what of the noise generated by the moving air itself? You can hear this clearly when you have a case full of "silent" fans, and it's every bit as annoying.
Mac G5: Lots of big, slow-turning fans... (Score:3, Interesting)
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 ][.
Re:Yes, much simpler than.. (Score:3, Interesting)
Re:Yes, much simpler than.. (Score:3, Interesting)
One of the many things I don't understand about current computer hardware is the segregation between quiet/small/laptop and big/noisy/desktop/server components. If you can design a low-noise and low-power component, why limit its use to laptops and other portable/embedded devices?
I understand there are real drawbacks to laptop components, such as underperforming hard drives. But cost should not be an issue; these components are expensive only because of the limited demand. Surely it would be cheaper to use the same component everywhere, instead of producing two kinds of everything.
I have always wondered (Score:3, Interesting)
It's a nice idea, but... (Score:1, Interesting)
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.
Re:Can the noise be more predictable? (Score:2, Interesting)
I expect a lot of the same principles apply.
One potential source of noise is rough edges. So get the finest sandpaper you can find and smooth the blades on the fan. The problem is that since it's plastic, it won't help much. You might get better results from using a material that's polishable.
How about the people on my bus? (Score:3, Interesting)
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.
HBHThe solution is DIY (Score:3, Interesting)
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.
My efforts to reduce PC noise (Score:3, Interesting)
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.
Re:noise cancellation (Score:5, Interesting)
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.
frictionless, less turbulent fans? (Score:4, Interesting)
Fan with more blades? (Score:2, Interesting)
Using a lower rpm, the fan with more blades could blow the same amount of air as a normal fan, but run MUCH quiter.
Re:Maybe its not the fan. Keep the Horse in front! (Score:3, Interesting)
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).