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Active Noise-Canceling Headsets In Server Rooms?
An anonymous reader asks: "Recently I co-located our computer room to a temporary hosting facility. It's a big shop, with everything you could want, along with quite a high dB of background noise. I've no desire to wear those silly little yellow earplugs for several hours when I'm on site there, and standard headsets are such non-IT apparel. Given that technology is the cure to many of todays evils I was wondering if any people had experimented with active noise canceling headphones and has something to say about them. Does anyone use any active noise canceling headsets in a computer room or data facility, and if so how good are they?"
http://www.amazon.com/Sony-MDR-NC50-Noise-Cancelin g-Headphones/dp/B0007N55OQ/sr=8-1/qid=1163179023/r ef=pd_bbs_sr_1/104-1893536-4549558?ie=UTF8&s=elect ronics
The customer reviews pretty much sum them up - I've even got one in there. They do a FANTASTIC job at filtering out our 500 servers, with or without playing music.
they work, are cheap, disposable, sanitary, and only take a few days to get used to wearing for hours every day. I worked in a high noise environment for years, and used the "Ears" brand - they're well worth the initial minor discomfort to have continued good hearing.
Um, No it doesn't. By playing the exact opposite wave, it Destroys the original wave, meaning there is now less intensity.
You obviously have never heard of destructive and constructive interference.
I've owned and sampled various active noise cancellation headphones. At best, I've found them to be good. At worst I've found them totally ineffective.
To attenuate high dB environments, I'd consider the "good" of headphones I've tried to be less than satisfactory, i.e., my subjective evaluation has been about a 10 dB or so drop in levels, good, but if you're looking to get rid of noise these won't do that. If the room is loud enough, I think they'd only lessen the noise to barely acceptable levels.
You mentioned you don't want to wear the silly yellow ear plugs... there are some available in other silly colors. ;-) On the other hand, you aren't likely to be anymore comfortable with headphones on the whole time, and you're going to look no less silly. I've found earplugs to be quite effective, and they're something you can get used to.
If you're looking to "use" headphones, i.e., listen to music, you might consider various ear-canal headphones. I own a pair of those, and aside from the amazing sound quality of the music, I get about a 30dB attenuation of ambient noise. Two birds with one stone. YMMV.
Good luck!
Check out the SAGE sysadmin toolbox page, and scooch down to "What's the scoop on hearing protectors and noise-cancelling headsets?". (The whole damn page is useful, too...)
Carousel is a lie!
I have a set of Phillip Noise Cancelling Headphones, they are only like $25.. it works awsomely..
Ad eundum quo nemo ante iit!
Exactly.
Sorta the same way -90 doesn't cancel out +90.
Oh, wait...
1+(-1)=0
Same goes for sound, if you send out a sound with the same volume and "shape" as the background noise but phase-inverted, you get silence.
In principle true, except no system is perfect and you will still get high amplitude spikes and beat frequencies.
-- Back to the shadows again...
If the sound cancels out, then that's because the amplitude is reduced as each peak from the source fills the trough of the cancellation, and vice versa. Low net amplitude is low net dBs, low energy, low power, not damaging.
I'm by no means an expert, but if I'm not hearing any sound, doesn't that mean that my inner ear isn't vibrating? Unless there is some kind of inaudible high or low-frequency sound in the source noise, it seems like cancelling the pressure changes would be effective. I'd worry that the system might fail for some reason though.
I have seen the future, and it is inconvenient.
A positive 90dB wave, plus a "negitive" opposite of it, will add to zero (If the headphones are perfect, but they are not, so add or subtract a few percent).
Review: (1) + (-1) = 0
Wonder what the public key field is for?
First, to reduce the sound:
0 69679
http://www.jr.com/JRProductPage.process?Product=4
These do an excellent job of just reducing the sound across the spectrum, so your 90db server room turns into 70db. In fact, I use these plugs while drumming to be able to hear properly (foam plugs kill the highs). An additional help with these plugs is that speech is still very clear.
I've also used some Sony in-ear headphones, and am thinking of ordering some of the Sennheiser phones. Now, these don't have active cancellation in them, but they do form a good fit (similar to the earplugs above) and can keep ambient noise to a comfortable level - but watch yourself; you may find youself still turning the music up too far to compensate for that little last bit, and cause more damage to your hearing.
I'd say earplugs would be 10x better; and with the earplugs above, you could play some music in the room and hear it properly... only problem there would be bugging others with your choice of music.
Karnal
My Philips HN100s (admittedly a rather low-end model) do very little as far as noises from a computer (drive whine, cooling fans, etc.) They're excellent against lower bass frequencies (automotive engine noise, airplane engine noise, lawnmower noise).
Also, wearing circumaural ANC headphones is going to be a lot more annoying than almost-invisible earplugs. The in-ear ANC headsets (like the Philips SHN2500s) are absolutely awful compared to good passive-isolating earphones or good earplugs. In fact, my experience with the SHN2500s was that they added more noise than they removed in most environments.
As far as in-ear passive isolating headphones, I have tried the following:
Sony MDR-EXsomethingorother - Silicone rubber earpieces, with rubber hooks that go over your ears. Extremely uncomfortable and not much isolation. $50
JVC HA-FX33 "Marshmallow" headphones - These STILL don't appear on JVC's website anywhere, and I have only seen them at Wal-Mart stores. $20, decent isolation, pretty comfortable, excellent sound.
Radio Shack "NR-1" noise isolating earphones - Great isolation and comfort, not very good bass response. I keep them around for extreme environments where isolation is more important than bass response and sound quality. $40
I haven't used any of the more expensive in-ear monitors. Shure E2cs and E3cs are popular, as are Westone UM1s and UM2s. The UM1/UM2 appear to use the exact same "Comply" tips as the Rat Shack units, so should have the same isolation and comfort, but hopefully better bass response and sound quality due to better drivers.
For the most extreme enviroments, such as the cabin of a Saab 340 turboprop aircraft, my personal favorite is a combo the Rat Shack in-ears connected to an audio source (laptop or iPod) with the Philips HN100s placed over them. Neither of them alone is sufficient for the interior cabin of a turboprop aircraft.
retrorocket.o not found, launch anyway?
But these systems are specifically designed to do the best job they can do to reduce amplitude as much as possible everywhere in the normal sound spectrum. If you've ever used an expensive pair of noise cancelling headphones, the first time it is incredibly surprising how much sound is destroyed. There is a significant amount of engineering that goes into these.
Uh...no.
If you're trying to cancel a 90dB wave, you generate the same 90dB wave, inverted. This means that every particle that receives a sound vibration in one direction receives an equal sound vibration in the opposite direction, resulting in a net movement of zero.
No vibration of the air means no vibration of the eardrum, which means no sound doing its mechanical damage to the moving pieces in your ear, which means no signal doing its neural damage inside your cochlea. Notably, earplugs do exactly the same thing to a lesser degree: they reduce the total transmission of vibration (that's what reducing the amplitude is, after all) into your ear canal.
In both cases, you haven't changed the total amount of energy reaching your ear, it's just that some portion of the kinetic energy (sound) that can damage your ear is now thermal energy that won't.
(Of course, noise-cancelling headphones have widely varying effectiveness in various regions of the audible sound spectrum, and won't do anything to prevent transmission of vibration from other parts of your body into your inner ear - but then, neither will softies)
Reality has a conservative bias: it conserves mass, energy, momentum...
I have a set of Targus AWM02US headphones and I use them in my lab, where my in-lab "desk" is directly next to a rack of Itaniums (loud), and even with the active canceling off the noise reduction is great. Regardless of which brand or model you decide on, if you're in a data center, you'll be glad to have them.
Denpending on what you want to accomplish there are different things to do.
Do you want the illusion of silence so you can concentrate?
Do you want silence to avoid long term damage of your ears?
Do you want to actually talk with other people?
If you dont want to use earplugs get a real hearing protector, they can be had without, with a speaker inside and with speakers and a microphone for talking to others.
Dont damage your ears for appealing looks (you wont pickup or get laid inside the server room anyway).
I do have an old pair of noise canceling earphones, and they do "mute" some sounds, but others are raised, voices go more clearly through, or so i percieve it, but that might be because the background sounds are not percieved by my brain.
Non-IT apparel? Aside from safety considerations, I'm not too concerned with what I wear in a facility. I know that it isn't always possible, but I avoid customer contact on the days I have physical work to do; besides, khakis and polo shirts are required IT wear, aren't they?
Standard hearing protection is a lot cheaper. You can have more than one set, and when you lose one, you're only out about $25. Since I have a motorcycle, I use moldex ear plugs; they work well, are cheap, and pack easily.
In the land of the blind, the one-eyed man is usually crucified.
Noise canceling headphones won't protect your hearing. I recommend those ear-buds that actually seal your ear canal, like SHURE, or Etymotic ones. Even Sony makes those now. They block out outside noise pretty well, you can still have your music, and protects your hearing to boot (if you don't play it too loudly, that is).
Will the War in Iraq get better or worse in 2007? Vote here
Somebody obviously never took physics. Go online and read about constructive and destructive interference and you'll see why you're wrong.
You may not like the stupid yellow foam earplugs, but there are better alternitves. Check out http://earplugstore.stores.yahoo.net/profmusearpl1 .html for instance. The idea is that they are both more comforatble and allow you to hear better even while reducing the volume. All of the musicians I have mixed for LOVE them and I've tried them and found them to be much more comfortable than regular foam plugs. In fact, I find having a large headset on, is uncomfortable for long periods and adds strain to your neck. Check them out, they aren't too expensive. (and I have no affilation with this paticular store, it's just the first site I found)
I use my Sennheiser noise cancelling headphones in computer rooms and other places with the same kind of noise, e.g. heavy airconditioning machinery. I'll never go anywhere near the noisiest rooms again without my headphones. They reduce the noise maybe 15 dB, it might not sound much but it's the difference of the world, particulary when staying in there for a long period. I bought my headset with airplanes in mind, but they work even better in computer rooms.
I have worked in server rooms and also ride a motorcycle. The noise in a server room is very similar to the wind noise when riding a motorcycle on the freeway. I wear earplugs from Howard Leight, the green disposables. They are very comfortable and very cheap, 200 pair for less than $25, which usually lasts me 2-3 years. I've used them in server rooms and on airplanes. They are very effective and you can hear people talk if they speak loudly. Here's a setup that I've been considering that you may find agreeable. It's a set of in-ear phones from Shure that have twin plugs, one for your music player and one for your cell phone. That way you can take phone calls without removing them.
o nes/ISeries/us_pa_i2c_content
s ories/CasesAdapters/us_pa_PTH_push_to_hear
http://www.shure.com/PersonalAudio/Products/Earph
To make talking to others easier they have this nifty little PTT device that plugs inline:
http://www.shure.com/PersonalAudio/Products/Acces
Both will cost you less than $200. The fit of the earphones will take some trial and error, but it's a great solution.
Stop by your local hardware store, and get a nice big pair of those headphone/earmuff style hearing protectors. You can find them in a few colors, or cover them with stickers, or mod them with LEDs, etc.
The biggest convenience of those things is being able to take them off easily, and not having to scour your ears daily to avoid having earwax all over. (with the little in-ear plugs) And they'll actually protect your hearing, to boot.
Noise canceling headsets can damage your ears. The sound pressure in a loud environment is still there, even if you can't hear it. If you are in a loud environment, one loud enough to damage your hearing, wear earplugs!!!
So while turning up the power on the headset will make the noise you can hear 'go away' the damage is still being done.
These are the best portable headphones i've ever used. They're not active noise cancelling, because they're so damn good they dont need to be. Put them in and be amazed. I used them extensively in a large (and very loud) server room and was very VERY impressed with their noise cancelling abilities.
o nes/ESeries/us_pa_E2c_content
http://www.shure.com/PersonalAudio/Products/Earph
Oh shit! I forgot to click "Post Anonymously"...
You could take some action to improve the acoustics of the server room itself. For example, sound absorbing ceiling and wall tiles, rugs, and sound deadening panels. Putting the panels on wheels allows you to move them and create quieter work zones inside the datacenter as needed.
Just ask the good Jedi how they feel about "Balance" now...
Rubbish - if you can't hear it, then the canceling has worked - it CANCELED the energy of the sound.
If someone goes to give you a hard shove, and your friend pushes back with the exact same energy at the exact same time (with a slight delay due to reaction time), you don't get shoved.
By your logic the energy of your friend's shove is somehow going to push on you.
Take some basic physics classes.
Bavarian Purity Law of Rice Krispie Squares: Rice Krispies, Marshmallows, Butter, Vanilla.
We have our own loud server room, and are not only looking for solutions to ease the noise, but to also facilitate communication in it. We have impromptu meetings at time with developers and techs that can last for long periods.
Are there any good headsets that not only cancel out noise, but also allow for a group of 6 people to communicate right next to each other without yelling?
You are absolutely correct. If you don't hear it, the sound isn't activating your inner ear. End of story. The original parent simply got the physics wrong. Even the reply that talked about "spikes" still coming through is wrong, if spikes were coming through you would hear them. Simple as that. And, having used noise cancelling headphones for years now, I can tell you that this simply doesn't happen. When being in noisy environments for a number of hours (say, a 15+ hour flight (well, flights), or in a particularly noisy computer room for a couple of days, I would (in the past) always end up with buzzing ears for days and sometimes a week afterwards (I have a small hearing damage in one of my ears because of an accident when I was young). This problem has gone away after I started using the noise cancelling headphones. (My set is a Sennheiser set, I would love to test Bose but they're hard to get buy (little or no retail), and expensive - so I don't know how good they are. Probably at least as good as Sennheiser, but the latter is the only type I've tried.)
No, that's not what happens. The sound is simply reflected. The speaker membrane acts as a rock-solid wall to the incoming sound waves because the current through the voice coil is just right to prevent the membrane from moving. Or in a different way: behind the speaker, the incoming wave and emitted wave cancel each other out. But on the opposite side of the speaker, away from you ear, a wave is emitted.
I'd also like to repeat what I mentioned a few weeks ago:
Maybe I was a bit too pessimistic about 10 dB reduction. For lower frequencies, like from engines, it can work quite well. But I wouldn't expect miracles when blocking the whitish noise from computer fans.
Avantslash: low-bandwidth mobile slashdot.
Except that you would HEAR this (and you don't hear any spikes). I tried a friend's Bose canceling headphones and they worked amazingly well. No loud spikes or beat frequencies.
Bavarian Purity Law of Rice Krispie Squares: Rice Krispies, Marshmallows, Butter, Vanilla.
The tried-and-true little yellow foam jobbies are great if you only need them once, and your budget is around $0.03. However, if you're going to be wearing them for longer, or if you are the sort of person that goes to a lot of concerts or clubs, there are better solutions.
One set that I highly, highly recommend are made by Etymotic Research, specifically their ER*20 High Fidelity Earplugs. They're comfortable, and sound isn't "muffled" by them. That is, going out to a club or a concert, the music sounds as good as it would without the plugs, only it's more comfortable. From experience, I can say that wearing them is literally like just turning down the volume on the world. Two people wearing these can even carry on a normal conversation in a noisy environment, provided they speak up sufficiently; I'd always found that the little yellow jobbies destroyed the sound enough to make conversations difficult at best.
Other earplugs more suited to long-term wear exist from a variety of manufacturers, and some quick google searching can help you find those. It's one of those things that, before I was introduced to these earplugs by an audiologist friend of mine, I would never have suspected existed out there.
That green slime had it coming.
I own several ANC/ENC headsets for use in aircraft. They are abso-friggin-lutely fantastic! The first time I tried one on I was completely sold on it. I was sitting next to a humming Coke machine, flipped the ANC switch, and... silence! My ears have thanked me ever since.
My best headset has a Noise Reduction Rating (passive) of 23 dB, and an active NRR of 20 dB, totalling about 43 dB of noise reduction. To say that you are still being pounded with 90dB of energy sounds implausable given that waves 180 degress out of phase with each other would completely destroy each other--drop two pebbles in the water and watch where the waves interfere with each other, the water will be still. Also, here's a bit of a sales pitch about ANR/ENC technology.
Noise canceling headphones do protect your hearing but most civilian models don't afford serious protection at those dB levels. The reason is that, if the headset is capable of generating antinoise that can prevent ear damage, it si equally capable (perhaps more capable) of generating *noise* that can damage your ears. That is a huge liability problem for the mass market.
Given the ease of making consumer models feed back (cup your hands just right over the earphones of a Sharper Image, Panasonic, or even Bose set, and you'll be rewarded with an ear-piercing squeal), I'd rather that the drivers simply not be capable of working with instant-deafness levels of sound pressure.
Military models are different -- the ANC headphones military chopper pilots wear reduce the bone-shaking noise of an open cockpit Huey, to a noise level comparable to a civilian sedan on the freeway (I had the pleasure of experiencing this in the early 1990s, flying recovery for a sounding rocket at White Sands). I imagine that the very best of the civilian models can do that too, but you won't find them in the catalog in your airplane seat-back or at the mall, more like Sporty's Pilot Shop.
No, that's not what happens. The sound is simply reflected. The speaker membrane acts as a rock-solid wall to the incoming sound waves because the current through the voice coil is just right to prevent the membrane from moving. Or in a different way: behind the speaker, the incoming wave and emitted wave cancel each other out. But on the opposite side of the speaker, away from you ear, a wave is emitted.
Huh. That makes perfect sense. I'd always just assumed you ended up with heat, because whenever it looks like energy has been lost, increased heat is a safe bet.
But you're saying that the wave emitted on the "outside" of the speaker, you get a reflected wave that now has all the energy of the incoming wave and the cancellation wave, right? Cool. Thanks for explaining that.
Reality has a conservative bias: it conserves mass, energy, momentum...
I know they are expensive, but the Bose QuietComfort 3 headphones are incredible. I use them almost every day to cut out most of the noise of the servers and AC units in the data center. You still hear a bit of the higher pitch noises coming from the fans but its bearable. Once you've had the headphones on for awhile and take them off you realize just how big the difference in sound is. It still surprises me sometimes. The difference from a cheaper set (say the Sony noise-cancelling) and the the Bose is really noticable. Also, the battery life is more then excellent. It goes for about 30+ hours on a 1 hour charge. Plus it comes with a nice case and airplane plug and 1/8" extender. Hell, you don't even have to plug them into anything. Sometime I just put them on when I'm reading and it takes care of the noise of my roommate playing CounterStrike.
ANC headphones are one solution amongst several. They certainly work, but they're not perfect. Noise cancelation isn't 100%, and depending on model, the range of frequencies they can actually counter may not be effective in your environment. With most of them, you can hear a low volume 'hiss' when they're just canceling noise and not playing music. Also note that the "over the ear" type are more effecive (they provide acoustic as well as active noise cancelation) and usually more comfortable than the less expensive "on the ear" types. Finally, most models have a permenantly connected earphone cable and ALL of them lose some, if not most, effectiveness when the batteries die.
I've tried several sets, and they certainly work at the noise levels and freqs I've encountered in the DC's and computer labs I've had to work in. Also great for air travel - which is what te technology was first developed for.
The cheapest solution are the foam earplugs. They're also generally more effective than ANC at protecting your hearing. They do, however, reduce ALL the sound, so conversation (already difficult) becomes more difficult. "In the ear" headphones (Shure or Etymotic, for example) can give the same level of hearing protection and provide music. Some of them have an external mic you can use to hear people talking. I went to a set of Ety's for air travel and find I can listen to music clearly at very low set volume while blocking out more external noise than the Bose or PlaneQuite active units did.
The "ugly", but possibly best, solution, is a set of over-the-ear hearing protectors as you see on construction sites or shooting ranges. They look kinda silly, but they have great sound attenuation.
Best for you will depend on your needs.
Foams are dirt cheap. Professional grade over the ear types are $20-$50 depending on how nice you want. ANC starts under $20 and goes well over $300. Same with in the ear headphones. Top end Shure units are something like $500.
Figure out what you want to do, and experiment.
Never attribute to malice what can as easily be the result of incompetence...
While fancy Bose or something might do even better, the difference between using my cancellers and just plain earplugs is night and day. They were just $30 Radio Shack specials, yet in the server room, it becomes dead silent. (The difference is so astonishing that if I'm wearing them when I walk in, I just plain don't notice the noise. If I then take them off, or turn them off, it's like I've stepped onto the deck of an aircraft carrier.)
Another non-functioning site was "uncertainty.microsoft.com."
The purpose of that site was not known.
As far as hearing protection goes, if you're going to be wearing them for any length of time, you owe it to yourself to get ones made by David Clark.
I don't work for them, I'm just a very satisfied customer and user of their products. Second-generation user of their products, actually; I have a set of DC hearing protectors that used to be my father's, that are getting on 40 years old now.
Their list of products are here. I have the model 10A, although if you have big ears that stick out, you probably want the 19A. Allegedly the model 27 is "deluxe," although I don't know in what way they're different. The 10A model is the one they've been making since basically the Earth stopped cooling, and I don't think you'd have a problem getting parts for them in the future.
If you want to spend some money, you can get basically the exact same product as the 10A hearing protectors, but made into headphones. These aren't active noise-cancelling, they're just passive noise-reduction, but they're probably the best you're ever going to find. Equipped with microphones, they're very popular for use in helicopters (watch in some movies and about 50% of the time you'll see DC headsets being used in helis). They have a lot of room inside, if your 'buds don't stick out too much I doubt you'd have a problem with this. Although it might be a reason to get the 19A model.
The 10A model has a noise reduction of 23dB, and unlike earplugs, they don't make your breathing echo in your head quite so much. If you got ones with speakers inside (headphones) it would mean you could play music, without having to jack the volume up to dangerous levels. Alternately, if you didn't want to spend the money on DC's headphones you could just wear earbuds and then put the passive protectors on over it.
The really nice thing about DC 'sets, is that they're designed to be worn for long periods. Unlike some cheaper ear protectors that just use a spring-metal band connected to the top of the ear cups (pretty much every set of hardware store or cheap shooting protectors are made like this), resulting in more pressure on your head at the top of the cups than at the bottom, the DC ones are designed so that the pressure of the cups is distributed evenly, so you don't get sore. Also, they adjust using set screws instead of just using friction, so you can adjust them to your head and lock them there; they won't slip around. They have nice replaceable foam ear rings, as well. (When the ones in mine started to break down, I wrote to them and they sent me a set of replacement ones free.)
I use my DC 10As for pistol shooting mostly, and they're hands-down the most comfortable ear protection I've ever worn. (And if you really need a lot of noise reduction, you can combine them with foam plugs for something like 46dB of noise reduction; that's enough to safely do high-power rifle indoors -- you'll feel the pressure in your eyes more than in your ears like that.)
You do get a lot of funny looks wearing them around, but if you're a geek and don't mind looking like a helicopter pilot, I don't think you'll find a better set of passive hearing protectors.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
subject pretty well sums it up... they are AMAZING (albeit expensive...)
-Dave
I'm not sure if this is true, and despite some Googling I can'f find any substantiation either way. There certainly are a lot of warnings from various people not to try and use active noise-reduction systems as "hearing protection," but I can't tell if that's just the manufacturers of same covering their asses from lawsuits, or if it comes from actual technical deficiencies in the systems.
I think the main problem with trying to use noise-cancellation as hearing protection, is that most systems only 'cancel' noise in a small part of the hearing spectrum, which is not where much of the damaging noise would be. IIRC, the most damaging sounds to your ears are high-pitched ones, and most noise cancellation systems filter out the lower sounds. Hearing protectors, like foam earplugs and circumaural earmuffs, actually filter out more high-pitched sounds than low-pitched ones (if you listen to someone talk, or to music, when wearing most passive suppression systems, it will sound "muffled" "bassy" or "thumpy".)
So the real reason I would be concerned about using active cancellation systems in a high-noise environment, is that they might block out the 'annoying' parts of the noise, but leave in high-SPL, high-frequency components that are still damaging, but easier to ignore. Because the human mind acclimates to sounds, even loud, damaging ones, with relative ease, you could think that you are protecting your hearing with an active system, but still get damage from the sounds your brain is ignoring.
Just to be safe, I would not want to use an active cancellation system, in any environment where the ambient SPL was already over safe levels. I think that their use is more appropriate in situations where the SPL is safe, yet annoying (on aircraft, possibly in a quiet server room, office near HVAC, etc.), or when you have already reduced the ambient SPL to a safe level using a passive system that is known to work. For example, many avionics headsets include active noise cancellation (I've used Bose ones in a helicopter, and played with the noise cancellation), in combination with fairly heavy passive dampening. The passive dampening alone reduces the sound to a safe level, the active suppression pushes it down below what most people find intrusive, so you can get that relaxing near-silence.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
I've got to second the in-ear canalphone recommendation. For one, they use less power (and don't require their own batteries) as most noise-cancelling phones do (better for portable player life). They have excellent broad-spectrum attenuation -- typically far superior to noise-cancelling. And if you invest in a decent pair (even the $80 Shure e2c's) they'll sound a heck of a lot better than most any noise-cancelling set. If you really step up to the plate, Shure's E5 series or Etymotic Research has some models that will simply blow you away -- Shure's even has a "push to hear" feature that allows you to hear outside noises clearly without removing the phones. And the sound quality on these higher-end models is right up there with the best -- period. The same can't be said for ANY noise-cancelling phones.
Of course you have to get used to having something stuck in your ear....
I've used Sony noise-cancelling headphones, and found them only marginally helpful. Foam earplugs helped block the fan noise, but, as others have commented, they can make you hyper-conscious of the sound of your breathing and your heartbeat; I also find them painful. The best solution I've found are ZEM hearing protectors. They're about $20, lightweight, and work well. They're great for planes, too.
I didn't want to buy the Bose without listening to them, but on one of my trips I found that Bose runs a kiosk in the Denver airport. I was able to try them out with my own iPod, so for me it was a good test - that's what I'm driving them with on trips, and I got to check them with the music I listen to rather than somebody else's selection. My wife prefers the Sennheisers, I prefer the Bose. The Sennheisers are lighter and sit on top of your ear, the Bose cover your ear and for me give slightly better noise reduction (although I believe that their new generation is more like the Sennheiser to reduce the weight). I suspect that the different preference is partly due to the different geometry of our ears, so your mileage may vary.
You could wear ear protection used in gun firing ranges and then put something inside them like earbuds or whatever else. I'm sure those work tons better for sound isolation, which would help the music sound tons better
I use some pretty nice passive ear protectors from a gun store.
Not pretty, and not as high-tech(or expensive) as the active canceling ones; but it works extremely well at turning the near-painful server room into near silence.
I'm sensitive to noise and have been using a combination of noise cancellers (Bose QuietComforts are far better than any others that I've tried) and ear plugs to survive noisy air conditioners, the din of "bull pen" cubicle farms, the hum of multi-hour plane trips, the roar of servers in machine rooms, and the rumble of gardeners at work in the early morning hours. Noise takes a big toll on you if you're exposed to it for a long time.
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e =AM%20Safety%20Master&GroupID=10
:)
When my (now) wife moved in with me, she couldn't sleep with my snoring. ): She tried my earplugs which helped with the noise, but was uncomfortable to wear over a long period of time. The problem is that my earplugs were too thick and dense for her much smaller ears. After we shopped around, we found much more comfortable ear plugs for her, and she is a much happier camper.
I went through a whole bunch of earplugs before I settled on the ones that I buy for myself and the ones that I buy for my wife -- you might need to do some searching of your own to find the right combination of noise suppression and long-wearing comfort.
This is the "small" earplug that I get for my wife: http://www.am-safety.com/category.asp?catalog_nam
This is the "big" earplug that I get for myself for maximum noise suppression; http://www.am-safety.com/category.asp?catalog_nam
If you buy noise cancellers, buy good ones. My wife and I tried Sharper Image's $100 ANR folding headphones because they were on sale at 50% off... They were terrible -- they cut the low-frequency noise effectively, but added so much high-frequency hiss that we hated them. The only problem I have with the Bose QC's is they are a bit too fragile for the way I handle portable devices*.
In extreme cases, the ear-plug + ANR combo is great. This is what we do when we're flying across the pond.
* Assurion hates me, heh...
Would it be possible to hack one of those headsets so that they output there inverse wave through larger speakers, say pointed at the back or front of your servers? Wouldn't you get a few db drop in the room by doing that?
Pluralitas non est ponenda sine neccesitate
Except, in your example, the friend's shove WILL push on you. So will that of the asshole who pushed you in the first place. You still have the possibility of bruises from both of them (if they pushed hard enough). The two pushes will just cancel out so that you're not going to go anywhere (assuming they both push equally).
It seems to me that giving an analogy where physical pain is a very possible outcome doesn't really make sense when trying to explain why noise canceling won't hurt you.
If you don't mind having things stuck in your ears, earplugs are the best bet. Either foam ones such as Hearos, or in-ear canalphones such as Etymotics if you want to be able to listen to music.
If you don't like having things stuck in your ears, I favor Sennheiser PXC-150 headphones. They have better active noise canceling than the original Bose QuietComfort (I haven't tried the latest rev), and better sound fidelity for music. They'll also fold up and fit in a pocket, unlike the Bose.
GCHQ Quantum Insert installed. If only our tongues were made of glass, how much more careful we would be when we speak
It matters on the noise.
If the noise is some idiot who meanders his way in, a baseball bat is the way to cancel it.
Have you read my journal today?
Dear Slashdot: I need to work in a server room for a few hours a day, it's really loud and I value my long term hearing. While I know that this is a solved problem and that ear plugs or ear muffs are the correct tool to deal with this; I don't like ear plugs and think ear muffs look stupid. Can you suggest a way for me to spend money on something that requires a battery so that I can continue to prop up my own insecurities about how much of a geek I am?
I wonder how feasible it would be to noise cancel an entire room. Instead of a tiny speaker on each ear, you have emitters and sensors at many points in the room.
It would have to be drastically more complex, since you'd be aiming to reduce noise throughout the room, rather than one stationary spot. Obviously if a detector across the room from you picks up a sound that originated from something next to you, it will detect less energy than your ears do, and will send an equally low inverted wave back to you, which will take even more loss. With multiple emitters, you could also have problems with over-amplification of the inverted wave, and maybe even feedback problems? The controller would have to be acutely aware of each detector/emitter, and probably even the physical layout of the room.
Or as a security application.. Your co-worker next to you can hear you talking at a normal level, but someone 10 feet away hears silence.... or for the big brothers out there, now you have microphones hidden all over the place.. record everything everywhere.
Sounds like a major PITA, but would be freaking cool if someone was working on this.
No, the outgoing wave carries the same energy as the incoming wave was carrying. As the speaker membrane doesn't move, it doesn't do any mechanical work (force times distance). Of course, there will be some losses because of the resistance of the wires, but as far as the interaction with the sound waves is concerned, there is no energy transfer.
Avantslash: low-bandwidth mobile slashdot.
Well, I suppose if you don't understand how a (working) set of noise canceling headphones DOES stop any acoustic energy from reaching your ears (otherwise you'd hear something), I can understand why you also don't follow the analogy.
Who said the friend wouldn't brace himself and lean into the push, thereby avoiding pushing on you?
I'll try again:
If the friend doesn't push back, you feel the energy of the unwanted push. If the friend does push the opponent (while bracing himself so you don't get touched) then you feel nothing.
Sigh..
Bavarian Purity Law of Rice Krispie Squares: Rice Krispies, Marshmallows, Butter, Vanilla.
Speaking as a percussionist of many years, I know firsthand that a good set of cast earplugs will make your day. I've spent countless hours in small, echoey rooms with a dozen high schoolers creating constant sound well beyond the hearing damage range. Marching snares (of the floating head variety) are GOD AWFUL LOUD.
Anyway, my point is this: have a set of earplugs made for you. They'll take a cast of each of your ears and they'll fit perfectly. You'll forget you're wearing them, save for the silence. Many include a little insert that can be pulled out to hear more sound if someone needs to talk to you. These will seriously deaden sound for you and many times I've wondered why I couldn't hear my engine when leaving, they're that comfortable.
If all my base are belong to you and I attempt to retrieve my base, does that mean I'm freebasing?
OK, lots of good advice has been put forth here already. One bit of it, I'll even repeat: If you need real ear protection, look at Etymotics.
That said, one of the points of a server room is that you should almost never be in it! Racking and wiring computers can take a while admittedly, but in our fairly large data centre (~10,000 ft^2), we probably have someone in the data centre maybe an hour a day, and that's spread across all groups (Unix, Intel, telecom, networking, backups, and building maintenance). I go down to the server room _maybe_ once a week to swap out a bad drive or something like.
If it's a one-time server room setup and install, I'd probably just suffer with the cheap earplugs. If you're spending that much time in the data centre after it's operational, you should definitely look at your policies and procedures, and see if you can change that.
"People who do stupid things with hazardous materials often die." -- Jim Davidson on alt.folklore.urban
I have a set of Philip consumer noice cancelling headphones. They are great at low end sound cancelling, but not at the higher frequencies. They work great when mowing the lawn on weekends or getting rid of motor noise but not at high pitched frequencies that a fan or a wood chipper generates. I was once in a room, not a server room, but a compressor room. The door was posted that you had to put on hearing protection before entering. From having experience with the room before, I had to wear both foam earplugs and over-the-ear hearing protectors to make the sound bearable. The bad part about is was that I would come out physically sore all over from the audio banging on the body. I would stick with the foam ones.
I'm guessing anything in the Bose QuietComfort series will be what you want if you can afford it. I'm in a server room now with the 2'nd version of these headphones and the sound is tolerable. There are at least 2000+ computers and I work on a cluster with over 11,000 fans.
Get those custom moulded earplugs. I've used the vented and filtered variety in a steel manufacturing shop and in the engine room of a ship, my hearing still tests very well. A hearing aid shop, a mobile hearing test service or Google would be good places to inquire, you have to have a mould done so you need a local company. They're usually around $50 and allow easier conversation than foam plugs or the big ear protectors, plus they last around 2 years. Damn good investement in my book.
I've also worn helicopter-pilot headsets - I don't know how they are for audiophile quality, but they did a good job for quieting the helicopeter noise, hearing the pilot talk through the headset, and hearing the dramatic-helicopter-tour-of-the-volcano background muzak. I couldn't head people talking to me who weren't using the microphone system.
Then there's always earplugs PLUS headsets, though that won't help if you're bothered by the sound of your breathing inside.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
I have tried several active noise reduction headsets for use in single engine piston aircraft, and tried the winners in noisier seats on commercial jets and in data centers.
My biggest lesson relevant to this discussion is the ANR headsets are most effective at low frequencies and relatively ineffective at high frequencies. And my experience with server farms is that the noise is mostly high frequency.
The three most significant heatsets I have tried were the Bose Aviation X (excellent but overpriced), the Bose QuietComfort 2 (works well for adults, best fit for children, not the best ANR), and the Lightspeed QFR-XC (the generic branded versions are cheap - 1/4 the price of a Bose X - excellent passive headsets, and quiet at the low end with ANR turned on). The Lightspeed headset also has an adapter for cellphones or music players.
In data centers I get some funny looks when wearing a Lightspeed headset, but for me it is the best choice since I sometimes have to be on the phone while at the server.
I use earplug headphones from Ultimate Ears http://www.ultimateears.com/superfi/superfi-3-stud io_clear.htm both in server rooms and at construction sites. The real advantage I see in passive over active cancellation is that passive phones don't need a power source other than your music player. Etymotic http://www.etymotic.com/ also makes some but I haven't tried them, I do however swear by Etymotic earplugs when I don't want music in my ears.
Sorry guys, I was wrong.
Learned something new today, though. I appreciate the constructive feedback I've gotten.
At least that's my experience. I went to the local Bose store to try them out, expecting to put them on and hoping to experience instant suppression of surrounding noise and conversation. No such luck. I checked out a pair at Sharper Image, too, and they claim 14 dB reduction. Even if the Bose ones (at $300) do more, 14 dB just isn't enough. Ear plugs are 20 dB+ and cost pennies.
If you want your music to sound better when there's ambient noise, noise cancelling headsets are probably great. If you want quiet, you want ear plugs.
You can get different sets of inserts for different frequency and db reduction characteristics. I got some because I tended to drive a very loud open-top roadster at 100+ mph all the time. It canceled the wind noise very well, but allowed me to hear the important stuff. Different inserts, perfect for shooting.
it depends. I've got some cheap noise-cancelling earphones (some generic brand), and in the office they are better than I have ever hoped. They kill air con rumble, people's voices are substantially quietened, and they are good for computers as well. What I really like is that I can turn the volume on my mp3s down, as I am somehwat paranoid about hearing loss.
But as an experiment I tried using them in my car. They definitely made things quieter... until they ran out of oomph, at which point they emit a loud impulsive noise. Fair enough, they were cheap.
As to the other claim, about ringing etc. These cheap headphones are non-adaptive. The developer basically measured the transmission loss of the headset, inverted that, and applies that inverted spectrum to the external mic, and mixes that into the audio stream. That's all it does. If you have adaptive filters then you can get weird effects such as ringing, but I don't see why a headphone would need an adaptive solution.
I've often wondered, could you get speakers that noise cancel in much the same way? I know it'd be next to impossible to get them precisely one(or any integer) away from the source - but perhaps a set of speakers forming a perimeter around the offending object?
Commodore64_love: I don't comprehend people who're so frightened of death that they'll bankrupt themselves to stay alive
I turn off my hearing aid when I go into my server room.
No, seriously.
Being deaf ain't half bad sometimes.
--Dave
I know this story is about the continuous noise in a server room, but I'd really like to hear any thoughts on dampening the noise in an open office.
I work in an open office environment with a lot of different sources of noice: People walking on the wooden floor, people talking and laughing, cell phones ringing, copiers and printers, etc. etc. So the scenario is a bit more complicated, as it isn't just a single type.
What I would really like, is to be able to work in peace and quiet. Right now I listen to music on my earphones, but it really isn't the best solution - I just replace the noise with something else.
Any thoughts on what would work best here?
sure you can start out with a pair of shure e2 inear-monitors. they will cancel out alot of background noise. however i find them to be uncomfortable. i certainly wouldn't want them all day in my ears, as they produce some pressure in the ear canal, similar to regular ear plugs (ohropax). YMMV
as a musician playing in a loud band, i've recently read alot about the topic. and sofar the most comfortable solutions seems to be, to go to an ear doctor and get a custom ear print. then get a silicon tip, for example the elacin ER 15, or ER 25, which effectively blocks 25db of sound. the advantage is a comfortable fit to the ears, and you can change out the filters for more or less dampening. however they aren't cheap (160-220 euros in my area).
another advantage is that you can later add an inear-monitor for listening to music. you simply add the inear-plugs on top of the elacin silicon. in effect: comfortable linear noise blocking + music. (make sure the inear-monitor is compatible with the elacin (eg: voicetronic vt-03) and some prefer the larger "conche"-elacin silicon for a tighter fit.)
Etymotic Researcy (www.etymotic.com) has a number of different ear plugs and noise attenuating headphones which are much nicer than the active noise canceling headphones, imo. The earplugs are very comfortable, and custom molds can be made.
09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0 is the magic number.
http://www.davidclark.com/ is what is used in many helicopters and light planes.
as a pathological consumer of headphones.....
I have tried numerous headsets;
I have favorite pair for movie watching (Sony MDR-F1) in queit settings.
I have a favorite pair for movie watching and music (Bose triport) in noisy (office, school) settings.
I have a favorite pair for music listening (Grado 325i) in queit settings
I have a favorite pair for short periods of time in planes and data centers (Shure E2C).
I have a favorite pair for LONG periods of time in planes and data centers (Bose QC2's).
I have the Shure E2C's and like them but I suspect that the poster is trying to avoid inner ear insertion, fit can be a problem
and something as simple as a yawn can reduce these to 0 reduction, as they are passive and great souding I would suggest
these *with* professional fitting, you can get molded earplugs to match.
Another poster noted that data center noise is higher up on the freq scale then say aircraft, and my experience
is the same.
The Bose QC2's that I bought for plane use render jet drone into something more like light wind noise,
that being said, the QC2's make both jet and data center noise quite barable and they live up to the 'comfort' part
of their name, extended wear isn't a problem, these cans are far from perfect though, initially I noticed a slight
sensation of 'pressure' while wearing them and the new QC3's are even more so noticable, because they are always active
there is a bit of hiss added and you can't turn it off (some cheaper sets allow passive use of the phones, good for silent and/or dead
battery scenarios, fortunately battery life is over 30 hours; think back to dolby C on tape, its subtle but its there) and this makes
these headphones annoying in silent situations. Its a lot of money to spend (300 USD) on headphones that should cost
closer to 125-150 range but they do work well. If you spend more then 2 eight hours shifts a week in a DC I wouldn't think
twice, if you don't, look at the shures and/or good plugs.
opinions for sure.
Unix, an obscure operating system developed by bored researchers in an attempt to get a better game playing experience.
I spend at least 8 hours a day in a loud-ass server room. It has phone switches, as well as servers, so it's quite loud. My solution is to crank up the stereo.
Works pretty well, though people walking by outside can hear it better than I can when I'm on the far side of the room.
You create your own reality - Leave mine to me.