JVC Headphones - As bad as I suspect?
July 10, 2007 9:11 PM   Subscribe

Two questions about noise cancelling headphones: 1) Are JVC HA-NC80s any good?; and 2) Are NC headphones (in general) bad for your hearing?

About Issue #1 - I am flying from NYC to Europe tomorrow and was at an electronics store buying a universal converter when I saw the JVC HA NC80s on sale. I bought a pair on impulse. Most serious headphone websites don't even seem to cover JVC, and the few reviews on CNET and Amazon make me highly dubious. Because of this, I'll probably leave them at home unopened and return them when I get back, but before I give up I wanted to see if any mefites had experience with this brand or model.

About Issue #2 - My incredibly limited understanding of noise cancellation is that it works by throwing the same frequency at your ear 180 degrees out of phase. Does this mean that even though it seems quieter, there are even more damaging waves hitting ear drums? Or does the phase cancellation effectively kill the damaging noise before it hits your ear? I'm guessing the latter, but I'm so cynical (and ignorant) that I have a hard time believing that newish consumer technologies like this aren't all secretly trying to kill me.
posted by blapst to Technology (11 answers total) 3 users marked this as a favorite
 
You are correct, the phase cancellation is not just tricking your ears into thinking there is no noise, it is making no noise get to your ears.
posted by aubilenon at 9:17 PM on July 10, 2007


aublie - thank you for easing my crazed mind on at least one subject pertaining to my demise in the robot apocalypse.
posted by blapst at 9:26 PM on July 10, 2007


The robots will still kill you, but you'll be able to clearly hear their actuators whir as they do it.
posted by aubilenon at 9:34 PM on July 10, 2007 [3 favorites]


When you get back and are ready to buy, I can highly recommend the Creative HN-700. They have much better noise suppression than the cheap Aiwas I had before, and much better sound quality too. I got a whale of a deal on 'em ($30) through a rebate via Buy.com but you their usual street price is $75-$90-ish. Very comfortable too.
posted by kindall at 11:20 PM on July 10, 2007


I'm wearing my JVC HA-NC100s as we speak. I've had one small problem with a part of the headset (not of the actual headphones) that periodically detaches and has to be reglued, else the headphones sit unevenly on my ears. This is the only problem I've had in at least a year and a half (I can't remember which Christmas I got them). Also, I've been known to drop things on the floor, and I've taken these with me around the world, so grain of salt and all.

Also, something I read about NC headphones suggested that they are actually better for your hearing because the noise-canceling effect means that the average wearer needs considerably less volume than before. YMMV.
posted by bijou at 12:00 AM on July 11, 2007


Hopefully not a derail, but in-canal earbuds like the Etymotic ER-6 and ER-4P work as well, if not better than, noise-canceling headphones. They're basically earbuds mated with earplugs. They've made my air travel and subway time much nicer (and quieter, too)
posted by zippy at 2:34 AM on July 11, 2007


I've had a great deal of success with non-NC headphones too., specifically Beyerdynamic DTX-50s. They fit snuggly into the ear (after changing the standard plug to one of the others sizes of the three supplied) and supress external noise quite well as a result. Prior to getting them I couldn't hear much just walking down a busy road. Now I can listen to spoken word on planes at mid volume without a problem. The quality is excellent.
posted by vbfg at 4:18 AM on July 11, 2007


My Sennheiser Evolutions (an old model) block out airplane noise well enough I don't need to turn the volume up much past street noise. I'm actually convinced they're indestructible, too.
posted by devilsbrigade at 4:24 AM on July 11, 2007


See also...
posted by spacewrench at 7:26 AM on July 11, 2007


About Issue #2 - My incredibly limited understanding of noise cancellation is that it works by throwing the same frequency at your ear 180 degrees out of phase. Does this mean that even though it seems quieter, there are even more damaging waves hitting ear drums? Or does the phase cancellation effectively kill the damaging noise before it hits your ear? I'm guessing the latter, but I'm so cynical (and ignorant) that I have a hard time believing that newish consumer technologies like this aren't all secretly trying to kill me.

In order to produce the inverted signal, there must be non-linear processing involved, and this will produce harmonics. However, this is probably not harmful. It is easiest to understand why by considering audible frequencies, and inaudible frequencies separately.

In the audible band, any harmful noises would be heard. So, baring an easily noticed (and very irritating) malfunction, they do not produce harmful noises in the audible band.

For frequencies above the audible band, there is no clear consensus on whether 'sound' in general can ever be harmful. From What Sounds Can Damage Hearing?:
Sounds must also be specified in terms of frequency or bandwidth, roughly like the span of keys on a piano. The range of audible frequencies extends from about 20 Hz, below the lowest notes on a piano, to at least 16,000 or 20,000 Hz, well above the highest notes on a piccolo. Most environmental noises include a wide band of frequencies and, by convention, are measured through the "A" filter in the sound-level meter and thus are designated in dB(A) units. It is not clear what effect, if any, sound outside the frequency range covered in dB(A) measurements may have on hearing. At this time, it is not known whether ultrasonic vibration will damage hearing.
Even if ultrasonic signals are harmful, headphones will not produce very intense levels at those frequencies. The transducers (speakers) are designed for the audible frequency spectrum, and the output level will decrease very quickly above 20kHz.
posted by Chuckles at 12:53 PM on July 11, 2007


just to follow up -- i ended up not returning them, and have been using them any time i fly for the past 9 months. and while i was relieved that they did cancel some noise, they really just make me hunger for better ones that filtered out LOTS of noise. also, the ear cups are a little small, and tend to make the ears hurt after prolonged use.
posted by blapst at 6:50 PM on May 1, 2008


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