Originally Posted by ravenx
Is there any truth in the "rumour" that the noise cancelling headsets are as worse than actually having the noise in the first place. These devices cancel the noise by creating an opposite and equal fequency which then cancels out the noise. You therefore have twice the "stuff" entering the ears. Any truth in this ?
Not true. They amplify the ambient noise and replay it inside the phones out of phase. Any noise that leaks into the phones remains 'in phase'. The 2 signals 'in phase' and 'out of phase' then cancel each other out. Net result is (ideally) zero noise level arrives at the ears.