RSSSCI FI Tech (great site) has a round up of headphones for your portable audio player (iPod, MAKE open source MP3 player, Zune...) - Link - A little too pricey for me, there's only one noise canceling headset that's under $50 that works, and you make it yourself... The Jackhammer headphones... These home-made hifi headphones work as well or better than Bose noise-cancelling headphones.
These are my old ones.
Ben's Jackhammer headphones.
Tim Anderson's helmet with headphones.
Great for airplanes and subways.
Except for these not being noise cancelling headphones, yes, it's a great idea.
Bose noise cancelling headphones actually cancel the sound by playing the noises coming from outside into your ear at the exact opposite time, so you don't hear them.
These simply cut the outside noise down by muffling it, which is a totally different technology.
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The over the ear bose phones depend on both. Next time you take a flight, look at the sky mall magazine. The noise canceling headphones with the best attenuaation plug way into your ear (and go for ~$400). I would be willing to bet that the bulk of the "noise canceling" is really just "noise supression" and the last few db's are the active noise canceling.
On another related note, I often wonder how hard it would be to use your notebook and a pair of headphones to do active noice canceling. You might need to play with the delay or phase a bit because the mic is not right at your ear, but it seems that you have a lot more hardware and recourses in a notebook then you would in the earcup cup of a headphone.
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When I tried noise cancelling headphones for helicopters, I'd say that there was about 15dB from the headphones without the active cancelling, and when they turned on the active cancellation, the difference was marked. Bose and others claim a 20dB drop, which is almost the same as most passives offer.
I know many makes of ear defender, and even those with head-crushing seals and ear plugs cannot reach the reported 42dB reductions found in some models of active headphones. That's 22dB from the headset, and another 20dB from the actual electronics.
Due to the combined systems, you can now hold an intelligable conversation with someone at sound pressure levels of 115dB! You'll not manage that with passive earphones.
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Matthew said: "I often wonder how hard it would be to use your notebook and a pair of headphones to do active noice canceling. You might need to play with the delay or phase a bit because the mic is not right at your ear, but it seems that you have a lot more hardware and recourses in a notebook then you would in the earcup cup of a headphone."
Active noise canceling that's done wrong has great potential to damage your hearing. The very best case is a signal exactly out of phase with the noise being canceled. The very worst case would be a signal exactly in phase with the sounds you're trying to cancel, doubling the dB your ears are experiencing.
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jswilson64 said: "The very worst case would be a signal exactly in phase with the sounds you're trying to cancel, doubling the dB your ears are experiencing."
Since the decibel scale is logarithmic (times 10), doubling the amplitude would not double the dB, it would increase it by about 3. Dangerous nonetheless, but not as bad as you make it out to be.
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The same can be said for any of the noise canceling phones. The mic is never is the compleatley correct spot. I still think with good earplugs a small amount of active noise canceling could be done in software in a notebook.
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