noise cancelling headphones

[sudu]

do noise cancelling headphones only work if you listen to something through them ie will they work if you wear the headphones attached to nothing?

[fo3nix]

no, they wont work like that (afaik). if you want that, get some workman-type noise blockers.

noise-cancelling 'phones work by listening to the outside noises, and playing back the exact reverse of what they hear. this works due to the superposition property of waves. if you fire one wave from left to right, and the exactly same one from right to left, then what you end up is with the two waves cancelling eachother out. this is what happens with these headphones.

[wideboy]

As fo3nix says, no. There is some advanced science involved and must be powered. Have a look here:-

http://reviews.cnet.com/4520-3000_7-1017728-1.html

(Had hoped that Howstuffworks.com would have a good article but it doesn't seem to have).

[alan30]

Bose headphones will cancel noise without any audio input. I have use dthem on planes just to cancel cabin roar. Bose site says;

You can remove the audio cable from the earcup and still enjoy the benefits of our Acoustic Noise Cancelling� technology.

[fo3nix]

alan: i was afraid someone like bose would have thought of that :)

but remember sudu that it'll still require power to cancel the noises.