Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!mcvax!ukc!strath-cs!nott-cs!ucl-cs!B.Witts From: B.Witts@ucl-cs.UUCP Newsgroups: sci.electronics Subject: Re: noise cancellation Message-ID: <208@ucl-cs.UUCP> Date: 17 Mar 89 10:51:16 GMT Sender: B.Witts@ucl-cs.UUCP Lines: 19 From: Bill Witts >Wouldn't it be good enough if only the microphone were on your head? >I would prefer a little mike plus IR transmitter on my head with the >bulky equipment in the corner over having to wear headphones all day... No, I think not - the inverse phase sound waves have to hit your ears in phase synch with the source of the noise. The speakers would have to know not only the sound waveform, but your head position in order to get the phasing right. Also, you would have all sorts of weird problems if the mike were within the anti-noise zone - as soon as the anti-noise cancelled the real noise, it would lose the sound info it needed, and would turn itself off, and then oscillate ... ... Bill