Article View: sci.electronics
Article #21132Re: noise cancellation
From: B.Witts
Date: Fri, 17 Mar 1989 10:51
Date: Fri, 17 Mar 1989 10:51
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From: Bill Witts <B.Witts@uk.ac.ucl.cs>
>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
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Path: arc1-ca.pugleaf.net!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