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Making Your Room Quiet 416

el_flynn writes "This may be a cure for those of you with loud computers, or perhaps those who spend lots of time in NOC rooms that generate lots of noise: mentions about a "Silence Machine" that gets rid of unwanted noise. I want one to quiet down my neighbour's loud dogs. " These are also being tested in cars, to make the car quieter. I've got a pair of the headphones that the article alludes to - they make airplane travel much nicer, and having something like this to cancel machine noise would be excellent.
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Making Your Room Quiet

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  • by slithytove ( 73811 ) on Thursday April 04, 2002 @01:15AM (#3282306) Homepage
    I tried out a friend's pair of Bose noise cancelling headphones with an iPod in a crouded restaurant the other day.
    I was absolutely amazed- I'd tried cheaper noise cancelling technology years ago and not really been able to tell the difference, but this time I was turning the noise cancellation on and off with glee!
    I hope they catch on so we can get some volume pricing going:)
    • by vandemar ( 82106 ) on Thursday April 04, 2002 @02:25AM (#3282643)
      The other day I let a friend of mine use my noise cancelling headphones to listen to a CD he just bought. After fiddling with his CD Walkman for a bit, he still wasn't able to hear anything on the headphones. It turned out the CD he bought was N'Sync's greatest hits album, and the headphones were actively cancelling out all the noise from it leaving only the real music (ie silence).
    • by HEbGb ( 6544 ) on Thursday April 04, 2002 @09:26AM (#3283618)
      Especially for air travelers - Sony makes some earbud noice cancelling headphones, the NC10 []. Their performance is much better than Bose's, and since they're so tiny, you can just slip them into you shirt pocket, rather than having to lug a huge package around with you (the Bose ones are HUGE).

      And, as I recall, Bose headphones have a pretty severe feedback problem. If you cover the port (say, by falling asleep and rolling over), you're welcomed to a delightful, ear-piercing shriek! So much for noise cancellation.

      Oh yea, the Sony's are less than half the price, too. I've been using a pair for years.
      • Would be to use Etymotic ER-6 or ER-4 (see etymotic's website []).

        Etymotic's canalphones use passive noise cancelling to cancel around 25dB and is way more effective than most of the active units you get. Most of the active units handle low frequency noise well but the high frequencies pass. Passive noise cancellation (Etymotics use the ol fashion earplugs) blocks the entire frequency range and is more effective than the Bose or Sony units as it does not add additional circuitry that could screw things up.

        Whats even more is that the Etymotics have *amazing* sound quality (which both the Bose and Sony truly lack), they are some of the best headphones out there, although a little expensive for most (ER-6 is $130 and ER-4 is $270 at Headroom []. And no I do not work for etymotic and I really didn't mean for this post to be an ad, if it came off as one :)
        • I tried these out when I was shopping for mine.

          What it comes down to is that the etymotics do have better sound quality, but their 'cancellation' is non-existant - they're simply passive 'sound blockers'. They don't negate the sound waves at all.

          They're really just well designed earplugs. They do block sound, but they do NOT 'cancel' it. So their efficacy at lower frequencies (such as plane rumble) is not very good.

          You're right that active noise cancellation doesn't work very well for high frequencies - but passive blocking does. So the Sony's gave me the best of both worlds - solid cancellation at low frequencies, and effective blocking of sound at higher frequencies.

    • I use a David Clark noise cancelling headset when I fly (I'm an instructor, so this is quite often). It's fantastic. It blocks the low frequency noise while still allowing me to hear things like the stall warning, gear horn, etc.

      In a single-engine airplane it makes a big difference. In a multi-engine airplane or jet, it's like magic. It makes you wonder how we ever got by without them.
    • What is the sound quality of those bose headphones though? I mean, compared to, say, some standard GOOD headphones.. like...
      Grado 60's, or Sennheiser HD330 or HD570's.
      (All around $60-$150)

      I mean with the noise cancelling turned on. What is the response? I ask only because in my experience a great many of the headphones out there are utter crap when it comes to decent sound reproduction. Most Sony headphones are crap until you get into their high end ones, you get 5x the quality from sennheiser or grado for the price. Same with most other brands.
      I have no experience with Bose, other than their speakers, which, although amazing at first listen, actually butcher the crap out of your audio. It sounds good, but it's not an accurate reproduction.
  • Dells (Score:4, Informative)

    by rosewood ( 99925 ) <(rosewood) (at) (> on Thursday April 04, 2002 @01:17AM (#3282317) Homepage Journal
    I am a PC consultant / PC Builder / Small time business OEM provider / AMD Fanboy

    Anyhoo, a company I do a lot of work for recently gave all agents brand spankin new Dells. While they are the shities P4s available and they are paired up with SDR mem - they are REALLY REALLY quiet. My trick of the trade is to get 1.2 GHz Durons and take the voltage down and underclock them, then they run nice and cool and there are some quiet fans out there and I use a nice sparkle psu that has a quiet fan on it, but I can still hear them in a small office. This P4 however is damn near silent. They have not been in dusty office environment long enough for me to tell you if the fans go over time, etc.

    I know the computer lab @ my school (in the chem library at least) has a bunch of the almost same Dells (same hardware, different case) and its whisper quiet in there

    You can do quiet cases with full clocked AMD AXPs - look for the screw mountable Zalman HSF @ - it comes with resistors to slow / quiet the fan down. Good airflow / tied down wires help a lot to keep the case quiet. Also, check out the sparkle PSUs -- lots of power, little noise.

    PPS - Silent water rigs are popular since only one fan is needed for the radiator and you can get pretty big fans that run nice and quiet
    • Yeah, I'm just realizing I need to get a new fan for my Athlon XP. I have a Thermalright SK-6 heatsink and a Delta fan that is loud as all hell. I want a quieter fan, but I'm a gamer and I need something that will still keep my CPU cool under heavy use. I haven't heard about any other fans that perform as well as this one, but are relatively quiet. If anyone has suggestions, then I'm open to ideas. Otherwise I may end up looking into this noise canceling thing. Though I don't think it'll help in my situation :(

    • Re:Dells (Score:2, Interesting)

      by Bnonn ( 553709 )
      The problem with watercooling, I would imagine, is not so much the cost as the weight. Water is damn heavy stuff; even a small amount will considerably add to the weight of a case. When you've already got those damn P4 heatsinks, a few hardrives, CD-RW and DVD and of course the PSU, it adds up.

      Course, I've never really hefted a water-cooled rig before, so I could be wrong, but that's always been the thing I've wondered about it. If it's as heavy as it sounds, it's no wonder I didn't see any at the last lan. Now, on the topic, I think the parent post does raise a good point. As Tim Williamson says in the article, "it probably will have some applications, [but] it would seem far easier and more sensible to avoid making noise in the first place." I have to agree. This sound dampener is really nifty, and proof-of-concept of something I've had in my book for a while because it's the kind of thing that's great for privacy in medbays etc, but it's treating the symptoms, not the cause. Obviously the cause can't always be treated, and there is surely place for these devices, but I think it's also important to try to prevent noise pollution simply by trying to create technologies etc that are quieter in the first place.

      Yeah, just shifting the cost, I know.

      • Well, I have built me one water rig

        I used a very expensive alluminum case and w/o the radiator and fans it was very VERY light. Adding the radiator, fan, and water did not add enough weight to it where it FELT heavier then your average case. My main rig however is a meter tall full tower w/ wheels. I thought about making it water cooled since I have more then enough space in here

        However, there are a lot of the $40 specials that if your two HDDs and CDRW + DVD are mounted in the 5.25" slots then you can removed the 3.5" hard drive bay (or dremel it out if you have to hold it there for a floppy drive) that give you pleny oh room for a radiator and fan. With proper securing mechanisms, that water rig will stay very tight during movement to LANs. Also, you can mount the Hard Drives in one of those silent holders that cushins the HDD so you wont have movement HDD issues to keep the case more protabale and even quieter.

  • White noise (Score:5, Funny)

    by sparcv9 ( 253182 ) on Thursday April 04, 2002 @01:18AM (#3282326)
    I don't know about the rest of you guys, but I find it difficult to sleep at night without the whoosh of the fans from the handful of servers I keep in my room. What kind of geek likes quiet machines?
    • Actually, I was going to mention that. The fans put me in some sort of happy-trance.. soft of like self-hypnosis. It usually takes me about 30 minutes longer to go to sleep WITHOUT fans of some sort.

      Even the sad thing with me, is that I know the particular pitch of the fans. I can tell which devices are on just by the pitch.
      • Even the sad thing with me, is that I know the particular pitch of the fans. I can tell which devices are on just by the pitch.
        Well, since mine are on 24/7, I don't have that kind of indicator. I do, however, enjoy the fact that the whooshes are not synchronous, so they produce a nice, ever-changing medly of white noise.
        • I wasnt quite clear. I dont JUST have computers. I have miscellanous electrical equipment. Amongst these things that have fans, there are: O-scope, 3 computers, signal anaylyzer, box fan to put heat outside (I love cracking my window open even in winter), a few rackmount devices (24 port hub, 16 port switch, 1u 400mHz p2), assorted power supplies to deliver regulated current throught my room (that pesky 120 vac is too, umm, yucky ;-).
    • by antibryce ( 124264 ) on Thursday April 04, 2002 @02:05AM (#3282587)

      I read that and immediately thought "Wow, sounds like my last roommate." Then I look at the userid and guess *IS* my former roommate. :)

    • what's even worse -- I have been known to wake up from a deep sleep in a panic because the fans suddenly go quiet (due to electrical failure).

      sad but true
  • by itsnotme ( 20905 ) on Thursday April 04, 2002 @01:20AM (#3282335) Homepage
    try breaking your eardrums, then you cant hear diddly.. and its cheaper than buying these 'quiet' solutions!

    I can say myself, I've been deaf since I was born ( I was born deaf ) so I can say that its the easiest solution since I cant hear diddly so all of my computers are supposedly "quiet" for me! Soundproof padding for my room? Nah! dont need it! :-)
  • Beyond! (Score:3, Insightful)

    by aznxk3vi17 ( 465030 ) on Thursday April 04, 2002 @01:20AM (#3282336)
    I saw a similar invention used in "Batman Beyond" a while ago... I no longer watch it of course, but yeah the idea is intriguing. What worries me is the possible military uses. By cancelling sound, armies could cause mass confusion by making illusions of silence, deafness, the list goes on. I fear the day when I am sitting at home, and all of a sudden, the fan of my computer goes silent, and the clicking of my keyboard goes quiet. We wouldn't even hear the explosion.
    • Re:Beyond! (Score:3, Interesting)

      by bpowell423 ( 208542 )
      The military's "been there, done that". There's a practice B52 bombing run the goes over my parents' house. Pretty cool as a kid, we'd hear a B52 coming, and look up in time to see it disappearing just over the treetops. One night, my dad was outside looking at the sky. All of the sudden, a B52 flys over, low enough to make out the cockpit windows (that's how low they typically flew). Only thing was, there was no sound, just wind. Absolutely true. Sound cancelling technology has been around for a long time. For that matter, so have holograms. So, class, which of those silent B52's is the real one?
  • Stuff on ears? (Score:2, Interesting)

    by limxdul ( 570562 )
    I have 24 boxes total in my house, 2 of which are mid to high range servers... When everything is on, noise is a huge factor. My room itself has 4 comps, and when they are all on i have to have some music playing to deafen them out. THen again, i don't want to look like a eskimo with devices all around my ear...
    • I find that positioning the computers in a V format (kinda like chevrons as in a V contains two computers with the fans pointing in) helps reduce the noise. If you set them up in this fashion: >>>>>> then you get a nice breeze through the middle (air circulation) and the fans cancel each other out.
  • by DreamMaster ( 175517 ) on Thursday April 04, 2002 @01:23AM (#3282351) Homepage
    The principle discussed in the article is exactly the way that, for years, the functioning of the translator has been described in the Star Trek series. In it, the translator device sampled an alien's voice, and quickly produced an out of phase sound wave to neutralise it. It then translates the voice and emits an English version of the speech.

    Of course, this device isn't as sophisticated - it needs continuous deterministic sound, so it can anticipate in advance what sounds to produce. But it's still interesting - perhaps one day we will have the technology to produce Star Trek translators. Or at least primitive ones designed to automatically convert a single spoken language. :)
    • by LadyLucky ( 546115 ) on Thursday April 04, 2002 @01:37AM (#3282438) Homepage
      No doubt it also placed a hologram over the image of the alien that seemed to be very adept at mouthing the english words at the same time.

      Why can't they just make like everyone else and put a fish in their ears?

    • Such a device is merely a combination of things we're working on.

      It would require a reliable speech recognition system, combine that with a translator, then a speech generator.

      Conceivably, using already available software you could program your computer to do it right now. Take a dictation program that can convert speech to text, run that through a translator, then reconvert it back to speech. It wouldnt be very accurate (as accurate as your translator is), but it would work roughly.

      The only problem is that no system will ever be able to do it star-trek style in perfect real time. Different positions of things like verbs in some languages require listening to the whole sentence before translating. German comes to mind as a language which tends to shove verbs to the end of a thought. This at the very least will create something of a pause. Which isnt too bad really.

      Where such a thing would be very beneficial would be carried by soldiers. If you put all those pieces of software in a carry-able platform, peacekeeping soldiers could use them to communicate more effectively with locals.

    • Older than Star Trek (Score:4, Interesting)

      by shaldannon ( 752 ) on Thursday April 04, 2002 @01:50AM (#3282515) Homepage
      As far as I'm aware, this idea was proposed by Arthur C. Clarke in his series Tales from the White Hart. The story goes that some guy in England at college (a professor, iirc) develops a silencer device. A scorned young man whose ex-girlfriend is in the big play borrows the device for the big evening and sneaks it into the auditorium. What happens next, I'll leave to the inquisitive reader. Suffice it to say that you have to account for energy balances.
    • I think it would be useful to have the silencing part, but no translator. Then I could finally enjoy watching TV with my wife as long as I nod once in a while.

  • this is cool! (Score:4, Interesting)

    by laserjet ( 170008 ) on Thursday April 04, 2002 @01:26AM (#3282373) Homepage
    I would love to have one of these, as I am a very light sleeper.

    That being said, the technology is the same thing as noise cancelling head phones (such as these [], these [], or these []). These headphones simply rock if you have not tried them.

    alternatively, you can use more traditional methods to quiet things down, like insulation. Putting some dynamat [] in your car will really dampen the noise and make it nice.

    One thing I have always wanted to try for fun, is get a really sophisticated sound cancellation system with many microphones and many large speakers to broadcast the "anti"sound, and put it in a large area like a park or the mall.

    then, don't tell anyone about it and watch the puzzled look on people's faces when they can't hear each other.

    maybe it's not possible, but I sure do think it would be funny.

  • bass (Score:5, Interesting)

    by astafas ( 232064 ) on Thursday April 04, 2002 @01:26AM (#3282379)
    I wonder if this will stop bass vibrations. I work nights and during the day when I try to sleep I get my neighbor playing his music real loud. I can't hear the music, but the vibrations from the bass keep me up until I get out of bed go over and knock on his door to get him to turn it down. This would help if it could block bass vibrations, but I don't think I want to spend a four digit sum on it.
    • Bass is easy. It is a slow waveform, relatively easy to cancel, and relatively hard to keep out with thick walls.

      Geez - 4 digits sums ! This is really an undergraduate project that would involve two microphones, a low pass filter, an amplifier, an audio amp, and a speaker.
      • its expensive because it uses advanced waveform processing in deciding what to cancel out and what not to.

        For example, cancel out your neighbor's bass, but not the conversation you're having with someone in the same room.

        • Hmmmm (Score:3, Insightful)

          by gvonk ( 107719 )
          I would imagine that you hold down a button and all of the sound it hears during that time it works to cancel out but then if you talk it knows that's not what you wanted to cancel out... like synchronizing a wireless mouse with the base station by holding the down a button to get it in sync...
      • by dattaway ( 3088 ) on Thursday April 04, 2002 @04:26AM (#3282931) Homepage Journal
        Eliminating bass can be much simpler than that with just an amplifier, speakers, and a... signal generator: position the speakers against the dorm wall where the source originates. Set the amplifier for test purposes at medium volume. Slowly calibrate the signal generator to achieve resonance of the walls. This is determined when picture frames rattle off the walls. Once this point is determined, maximize amplifier output. The resonant energy building within the walls will then be transparently delivered to the client in what can be described as a non-maskable interrupt.

        What can be described after that is guaranteed to be silence. Except for breakage of items in the host's bookshelves, etc... Slight profanity may be also side effect. Use with caution and deny any knowledge when questioned.
    • I wonder if this will stop bass vibrations.

      I wondered about this too, when I first read about it fifteen or twenty years ago. (I think it was an article in New Scientist then too.)

      Anyhow IANAP (I am not a physicist), but it seemed to me that for the waves to be exactly out of phase when arriving at your ear, the source of the anti-noise should be as close as possible to the noise -- or it should be right at your ear. If the anti-noise generator were 180 degrees from the source of the noise, as you approached or retreated from the noise sources, the two waves would go in and out of phase. The shorter the wavelength the more critical the location of the anti-noise generator.

      Bearing in mind IANAP, but it seems to me that this technology would work best with Bass.

    • Re:bass (Score:5, Funny)

      by daeley ( 126313 ) on Thursday April 04, 2002 @04:48AM (#3282999) Homepage
      I wonder if this will stop bass vibrations.

      I didn't realize they made that much noise. They're only fish, after all. I suggest staying out of the water. ;-)
  • Cancles (Score:2, Offtopic)

    I remember at the end of the NFL season, John Madden was going on and on about cankles. They'd zoom in on some guy's cankles, and he'd circle 'em. Pretty funny stuff.
  • Fix My Tinnitus (Score:3, Interesting)

    by Boulder Geek ( 137307 ) <> on Thursday April 04, 2002 @01:32AM (#3282412)
    Perhaps these bright folks can come up with something to fix my tinnitus. I can't even stay in a truly quiet room without going half mad from the ringing in my ears.
    • Re:Fix My Tinnitus (Score:3, Interesting)

      by ross.w ( 87751 )
      Jaycar Electronics in Australia have a kit for a white/pink noise generator that is supposed to help with this. The thoery is that the white noise drowns out the ringing but isn't intrusive. I don't know how effective it is. Jaycar Web site []
  • This was already done in the Get Smart! [] T.V. series.
  • How many early Monday morning lectures did I pray for something like this? Every teenager who reads about this is getting a read on their parent's voice(s).
  • I remember hearing of this technology/idea about ten years ago on a technology show called "Beyond 2000" (anyone else remember that show?)

    The suggested uses for the noise cancelling device was actually to place the device on the actual noise-making machine, not to create a device that "cleans" the area of noise, like the device mentioned in the article or like the noise cancelling headphones.

    The idea was to create things like noiseless lawn mowers and noiseless vacuum cleaners. I always wondered why I never saw these devices.

    This unit seems useful in that it can block out certain types of noise, but considering these people expect to charge over $1400 US for this, I can see why there never was a noiseless lawn mower...
  • In-box silencer (Score:4, Insightful)

    by el_flynn ( 1279 ) on Thursday April 04, 2002 @01:44AM (#3282484) Homepage

    How about this idea: have an extra soundcard installed in your machine, hook it up to a small mic and speaker, and put the mic and speaker inside the PC casing.

    Input from the mic would be fed to some app that could analyze the sound coming in, generate the appropriate cancellation frequencies and output via the speaker. Tada - quiet PC!

    Of course you wouldn't want the mic to be on continuously - there would be feedback when the mic accepts signals from the speakers. But we could possibly run a cron job that turns on the mic while shutting the soundcard output, and perform the analysis once every minute/5 minutes/whatever your fancy. This would be a good way to make use of your spare cycles.


  • is what happens at the finges of this "shadow of silence". Does it start to break down such that the anti-noise and the noise become in phase again, and you get an area of double-the-noise?

    This is a lot more complicated than headphones. Headphones are relatively one-dimensional (one microphone, one speaker, one eardrum per circuit) - the only thing you have to worry about is not generating feedback.

    This seems to be a more complicated 3-dimensional solution, and it'll have much more complicated problems. Does this cancel noise effectively in corners? Will a computer monitor cast a non-noise-canceled shadow? Is there a limit to the noise source (can it be all around you, or must it be generated in one specific place?)

    questions... looking forward to the answers!
  • Save money (Score:5, Interesting)

    by shepd ( 155729 ) <> on Thursday April 04, 2002 @01:45AM (#3282486) Homepage Journal
    Build this [].

    Cost? About $10 - $20 depending on how much you have lying around. Best thing? It lets you use any headphones you like instead of being stuck with the inferior quality of many noise cancelling headphones.

    I've done it and it compares well to most sub $100 noise cancelling headphones.
  • by 0xB ( 568582 ) on Thursday April 04, 2002 @01:49AM (#3282511)

    So, there is a noise source producing sound energy and I have a so-called noise cancelling machine producing out-of-phase sound energy.

    The end result is no sound, therefore energy has been destroyed.

    This violates all the fundamental rules of nature.

    I urge you not to build this thing ... you will destroy us all in a terrible singularity of destruction.
    • Energy is not lost. Sound is a wave, the canceling sound is a mirror wave. When two sounds meet you detect both but at one point you have to measure them both. So you take the average of the two and result is 0. You aren't destroying them, you're just taking the average as that's what we detect.
      The energy still passes through. It's been studied for a long time (play with a slinky, wave from each end, you'll see parts cancel each other out but the waves still carry through)
    • by Arthur C Clarke, in the collection "Tales From The White Hart" is exactly this scenario. Poor Fenton, blows up the concert hall. With him in it...
  • by Animats ( 122034 ) on Thursday April 04, 2002 @01:54AM (#3282535) Homepage
    Noise-cancelling systems have been around for a while. Basically, they work only when the cancelling speaker is within a fraction of a wavelength of the listener. It's a speed of sound limitation. You can cancel 100Hz for several feet, but 1000Hz for only a few inches. That's why noise-cancelling headphones work well, but large-area systems don't.

    You could build a system that cancels for a small target area from a distance, but it's going to produce twice the sound in other places.

  • Um... (Score:3, Funny)

    by Wakko Warner ( 324 ) on Thursday April 04, 2002 @01:58AM (#3282553) Homepage Journal
    I want one to quiet down my neighbour's loud dogs.

    You know, they make a .45 caliber machine which performs this job adequately...been around for years.

    - A.P.
    • My grandfather did something better: he took a signal generator and hooked it to his amplifier/stereo, then left it on all night at max volume but at "dog whistle" frequencies... sure, he had to put up with one night of dog whining, but it cured the problem after that...
  • You mention that they are being tested in a car. Personally my car runs rather quietly, so it's not a problem. Sure, it would be nice to have it even quieter, but it occured to me that it might be quite a frequency range someone would want to block out (wind through cracks, outside noise, etc.) I would find it very odd for people who are screaming about the use of cellphones in cars to support something that can block noise and lower a drivers alertness to that enviroment around him. IT's a nice idea, perhaps it would be a good idea in a bus or something like that. I know that it's designed for 'just certain frequencies' but one has to wonder if it couldn't malfunction, or somehow something else could be in a close enough frequency range that it would get blocked too by accident? Still a nice idea though...
  • Car noise-cancelling (Score:4, Interesting)

    by ColaMan ( 37550 ) on Thursday April 04, 2002 @02:14AM (#3282610) Journal
    I remember seeing a long time ago on the TV a system similar fitted to an exhaust on a pokey 4 cylinder Audi. The car was practically silent, and people had a lot of trouble stalling the car when pulling away from a standstill, because you had no real feedback on engine RPM.

    Best bit was that after the car was 'silent', they simply put some nice beefy speakers in the car, linked it to engine RPM and load, and added a bit of computer wizardy. Suddenly the Audi sounded a whole lot more like a Ferrari, or at the flick of a switch , a F1 car (with 12,000 rpm 'wired' to about 4500 real engine rpm), they even had (heh) a jet turbine, but it was a bit crappy, cause turbines don't quite spool up like 4 cylinder cars do :-)

    The presenter was having a ball, caning this little car around town - from the camera's position in the car it was pretty realistic.

    Pretty much the 'killer app' for noise-cancelling tech in my opinion.
  • by cjsnell ( 5825 ) on Thursday April 04, 2002 @02:25AM (#3282646) Journal

    Give Noise [] a try. It's free and it works pretty well for me.

    A little tip: I think you'll find that pink noise works best if it's being generated from a source that sits between you and the noise you're trying to block out.

    Another tip: pink noise are also good at keeping your noise masked. If you want to have a conversation with your girlfriend and don't want your roommate listening in, turn on some pink noise.
  • I'm surprised there's no (insert Dr Evil) "Open Source" software solution for realtime noise cancellation. I wouldnt mind a daemon constantly feeding my stereo the inverted-phase sound of my rooms ambient noise.

    Here's a challenge, implement it in one line of Perl :)
    Record -> invert -> playback
    for() { read("/dev/mic", buf); buf = buf * (-1); write("/dev/dsp", bug);} //whatever

    Yes, I have google'd & freshmeat'ed...

  • by AlexOsadzinski ( 221254 ) on Thursday April 04, 2002 @02:46AM (#3282719) Homepage
    This (noise-cancelling) technology transformed flying in general aviation aircraft a few years ago. An unpressurized single-engine aircraft can be very noisy, with a big fan a few feet in front of the pilot's face pulling the 'plane along. Sound insulation material is heavy, which you don't want in today's load-challenged GA aircraft. I use cheap ($300) automatic noise reduction (ANR) headsets when flying, and the difference is amazing when you turn them on. This technology works much better at low frequencies than high, and the tiring low-frequency rumble of a big piston engine just goes away.
  • If I recall correctly, ANR involves adding sound waves together to cancel each other out (as the waves are out of phase by half). This can't be a perfect implementation as there are many frequencies of sounds that are emitted from a computer at different times.

    Would it not be better for case manufacturers to manufacutre boxes that are sealed (sound proof). No air vents. Plus a tiny air compressor (air conditioning) inside that keeps the temperature, humidity at desireable levels. It would also remove what little dust is present too.

    Current levels of technology could implement this easily and cheapily. Prevention is better than cure. This is a simple solution, not a bandage fix.

    "I would like to change the world, but Microsoft will never give away any source code!"
    • I'm curious where all the air from the air compressor goes? Seems like it would create a lot of pressure on the box. You'd also need some hefty insulation, which would make the temperature problem even worse.

      If you want a quiet computer, try an iMac. No fan = little noise. You hear the hard drive and cd drive occasionally but that's it.
  • I had heard that 10,000 RPM drives were really noisy so I was anxious about ever using one since my office is already very noisy (4 computers).

    But I wanted good performance for a machine I was converting to a dedicated fileserver for my home office (finally a machine I could leave running Linux all the time, without having to reboot, running Samba, Netatalk and NFS for all my machines). So I decided to try the Atlas 10k III. []

    The one I ordered was a Quantum, but I guess they got bought out by Maxtor, or something, anyway Quantum is still around but only sells tape drives now.

    I read somewhere that the 10k III's were quieter than previous 10,000 RPM drives so I was pretty hopeful.

    My first drive didn't work. I tried it at first in my mac on an adaptec 29160, but the 29160 didn't detect it. I thought it wasn't spinning up because I couldn't hear it.

    Maxtor sent me an advance RMA (secured by a credit card) and I got the new drive today. I have 30 days to return the broken drive or else they'll charge my card.

    The web page above says they are Ultra320 but the drive I have is labeled Ultra160. No matter, really, I don't think one drive can sustain a 320 MB/sec transfer rate - these high transfer rates are most useful for RAIDs.

    I was distressed when I put the new drive in my PC on an adaptec 39160, because I couldn't hear it at all! There is another drive in the box, an old 2 GB IDE drive with Windows 2000, and the old drive completely covers up any sound coming out of the 10kIII.

    I was really upset until I went into the Adaptec SCSI utility to test and format the drive, which checked out fine.

    I'm really impressed. My wife wants me to get these for all our machines.

    I'm installing just the bare essentials of Debian potato on it as I write these, and then I'm going to use debian's go-woody script to update it to woody.

    Enterprise server admins might be skeptical of running beta software on a fileserver, but I've been running unstable (sid) on my Mac for months with few problems. My only concern is which kernel is the best, I want to run a 2.4 kernel on it and I'm not sure which I should use.

  • This would be great for recording audio direct into the computer, if you could cancel out the fan noise but still keep the full frequency range of what you're recording. Sounds unlikely though. It'd mean I can take my machine out of the closet though!

    Hmm, now that I think of it, anyone have any ideas about a way to temorarily shut off the fan? I've got a Mac G4 tower. Maybe there's a way to get to it software wise, but I'd guess I'd probably have to wind up doing a hardware mod--make a switch to turn on/off the power to the fan (this would be so I could shut off the fan, record a few minutes of audio, then turn it back on). Or is it a bad idea to shut off the fan for even a few minutes?

    I'd just about go into conniptions if this techology could be used to restore old blues recordings and get rid of the scratchiness. Some have so much scratch and hiss they're almost unlistenable, like some Skip James or Blind Lemon Jefferson tracks. You have to really listen to hear the nuances of what they're playing. But if they could take out the scratches and leave all the sound... Oooh, baby.
  • This is really nice. I have actually been thinking a LOT about this recently.

    In the past my 'server' has just been a Micron PC with SCSI and 512M... The nice thing about this has been that it is cheap and quiet.

    I can always hear it in the background but it does put me to sleep and the white noise keeps the sound of the busy SF streets from waking me up.

    The problem is that chicks don't dig it. When I have a girl spend the night they always complain that they can't sleep. If they are REALLY hot sometimes I will just shutoff the machine :)

    Then I got a *really* good deal on a 5U server. The only problem is that it is LOUD AS HELL! Then I had to swap my room/office situation around.

    This made me think... I think the white noise is TOTALLY not worth it. I have started to notice s slight ringing in my ears when I am in total silence. I am just concerned that it might be this constant white noise causing the problem.

    So I might buy this thing... see if it improves the situation..

    knock on wood
  • by joss ( 1346 )
    I find a shotgun quietens the neighbours dogs better than anything.
  • by Eil ( 82413 ) on Thursday April 04, 2002 @05:36AM (#3283110) Homepage Journal

    Does anyone ever consider that I might *want* noise? The dorms I live in are so damn loud that I'll do anything to bring the ambient noise above the human- and stereo-created noise threshold.

    Right now I've got a non-functional AC unit and dual in-window fans going primarily for this purpose alone. The frige is right next to my bed and since I don't have any money for food, I sometimes leave the door propped open just so the compressor runs and lulls me to sleep. I'm also considering buying a monster box fan to put next to my bed so my frige doesn't have to work so hard. (Or if I actually want to put anything in it.)

    And don't get me started on my computer. I think my neighbor can tell when I shut this thing off.

    For the curious, I have tried those anti-noise machines and noise-cancelling headphones, but they don't take care of 99% of the problem for me: bass. Until I started working nights, I'd usually be up until the wee hours of the morning because some dipshit wants to have a Jurassic Park marathon with his dipshit buddies. Let me tell you how fun that is when I had to get up a 6AM for work every day.

    And yes, I have also tried earplugs, but again, they don't block out the bass... the sound has such a low frequency that it travels through your skull rather than through your ear canal.

    • For the curious, I have tried those anti-noise machines and noise-cancelling headphones, but they don't take care of 99% of the problem for me: bass

      Yeah, the guy in the next cubicle has the "Billy the Big-Mouthed Bass". He has it on motion-detection, and nothing is more annoying that a fish that jumps out and sings when I go to the bathroom.

  • You will only have small quiet areas unless you purchase many of these sound-damping speakers.

    NOT an alternative for just booting that AMD and getting a Pentium...

  • I've got a sony headphones []. I picked them up for about US$100 at the airport in Narita (Tokyo). In the airplane, they allow you to hear the movie at the lowest setting. In a quiet room they produce a constant buzz. The $1500 Bose aviation headsets also do the same thing but they have nice ear cups that help knock off about 30 db.
  • This doesn't have much point really, but the kind of noises that piss people off are completely different.

    I have two computers on in my room, neither of which are quiet. I can tell which HDs out of the 4 are on, and if any of the CPU fans break. I sleep through this all fine unless some heavy disk access happens, or I hear one of the fans go off. However, if I leave the amp up high, and the speakers hiss even slightly, I can't sleep. My girlfriend also isn't too impressed with the level of noise.

    However, at hers, she only has a little laptop. I can't sleep with the high pitch hiss/whine that the HD makes, or the horrible forced air noise the tiny fan makes - and it isn't that I'm not used to it.

    Whenever we do crew things for shows, and I need to sleep during the performance so I can work afterwards, I find sleeping behind the speaker stacks is a great place... the treble is cut because it is more directional, but the base stays, and it's quite relaxing. I can even fall asleep in clubs, base is kind of relaxing. It is a different sort of sleep from usual - very hard to wake up, and you get very vivid dreams.

    So, you'd think I was fine with noise. But I can't stand working in co-lo facilities. It's not so bad in a cluster room, or somewhere all the computers are the same... but when you have 300 machines each with two fans, HD arrays, loads of raqs, then all the different noises combine, and working in there on anything more complex than running cables is impossible. I was working on a few servers for about 12 hours one day, and had a huge supply of Dr Peppers, so hadn't moved much... when I got up to leave I felt so dizzy, and I think it was a result of the noise. I tripped over a bit of cat 5 and took out a server as well...
  • What about energy conversation?

    As far I've learned wave canceling does not work globally by physics. If you have 2 waves, they may cancel each other out on some places, but double up on other places.

    If both waves would cancel each other of completely, where did their energy go???????
  • Complex computer... (Score:2, Interesting)

    by Bnonn ( 553709 )
    Disclaimer: ianal, but there may be a really obvious reason why this is a dumb question.

    The article states that to dampen complex noise like speech in realtime, a powerful computer must be used. I'm wondering why. If you have the speech going into the system to be cancelled, isn't there a more simple way to sample the amplitude and just amplify that sound to the right level and pump it through some kind of inversion circuit and out the speakers?

    I dunno, maybe an "inversion circuit" isn't possible, but you've already got that sound to work with; all you have to do is put it 180 out of phase. It seems like that should be fairly simple. Kind of a shame to complicate such an elegant idea with anything more than basic computer-aided sampling. Maybe I'm underestimating the difficulty though.

  • Many years ago, Bose produced a set of noise-cancellation headphones used for aviation purposes. They're pretty damn cool, and pretty damn expensive.

    Also, about 5 years back, Lotus had actually developed technology to cancel out engine noise in the cockpit of their cars.
    Funny thing about that one was that, though they developed the technology, the chose not to deploy it on their vehicles as their signature tinny engine sound was something Lotus owners really liked about the cars.

  • OK, so we all want to have a smoot, quite ride, but do we really want to have noise reducers that artificially remove sound? I don't think so. Think about it, what if you need to hear the firetruck screaming down the street headed your way. What if your engine starts making funny noises but you can't hear it well enough to know something's wrong. What will it make your stereo sound like? These kind of issues are endless, I just don't think it's a good idea.
  • ... (besides the obvious solution of turning the computer off and reading a book, that is) is to move it out of the room. If Larry Ellison is still selling his network computers... I'm in the market. I've moved all but one computer into a rack down in the basement and would move the remaining one if I could find an really quiet desktop device like an X-terminal that I could hang my 19-in monitor off of. I'd rather listen to my stereo than whirring disk drives and muffin fans. Any pointers on where the affordable devices like this are for sale (HDS's prices for their X-terminals are steeper than I'd like to pay)?

    Headphone? Seems stupid and, ultimately, uncomfortable for long-term wearing. (Though they might be nice -- along with some long-johns -- for those stints I sometimes spend in the data center doing upgrades. :-) )

  • Typical (Score:3, Funny)

    by sharkey ( 16670 ) on Thursday April 04, 2002 @12:13PM (#3284552)
    Isn't that just like the typical Slashdotter, making things SOOOO much more complicated than needed? If the PCs and equipment in your room are unacceptably loud...
    wait for it
  • Like a lot of others, I was interested in this, thinking that it might be a consumer device. I went looking though, and found this article from the bombay IEEE student newsletter [] which talks about the device. It says " The cost according to Prof. Wright is likely to be a few thousand pounds making it practical only for commercial use."

    On the other hand, the article also has some (thin) technical details:

    For the technically inclined, this facility measures 6m x 6m x 5m; the eight channel system is based on a Texas instruments tms320c32 processor using a two tap filter and a circular buffer technique to implement the delayed version of the update algorithm. This allows easy algorithm implementation in software and significantly reduces computation time for a large number of channels a 16 - input, 8 - output. PC 16108 provides a 12-bit interface with the external equipment. This board contains three selectable levels of gain: 1,10,100.
    Does anyone know about the latency involved with using a tms320c32? It might be possible to rig a software solution to run on a PC, perhaps leading to a homebrew version.

    Has anyone had any experience doing programming of this nature? Bear in mind that response time would have to be very low to cancel noise that you didn't predict (such as low-frequency hums, fan noise, etc).

  • In my case, I got used to sleep with the computers turned on in the bedroom, the idea is that when everything is totally silent, I hear all the unregular noises, clicks, walking, neighbour yelling, whatever.. the computer noise is regular and after many years I guess my brain got used to that specific frequency and it doesn't stop me from sleeping at all... If I turn everything off, I wake up at any unregular sound, and I find it very irritating.

    Man that will be weird when the girlfriend will move in. I just hope that one won't do the mistake of asking me to chose between her and the computers :)

God help those who do not help themselves. -- Wilson Mizner