Article View: sci.physics
Article #7739Re: noise cancellation
From: Greg Wageman
Date: Wed, 22 Mar 1989 00:21
Date: Wed, 22 Mar 1989 00:21
28 lines
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1749 bytes
In article <453@corpane.UUCP> sparks@corpane.UUCP (John Sparks) writes: > >Hmm, In theory you can try taking two speakers from a stereo system and >wire one of them opposite polarity from the other. Then when one cone >is extending the other is retracting. The two sound sources will be >180 degrees out of phase with one another. Make sure you feed the same sound >into both speakers. > >But in reality this won't work. Since each sound source is the center of >a 3 dimensional spheroid of sound waves, They would have to both be located >in the exact same space in order to cancel out each other. This isn't quite true. There will be places (nodes) in space where the waves will cancel each other. The real trick would be to guarantee that one of these nodes is where you want it to be. Longish .signature follows. Skip now, or don't complain! Greg Wageman DOMAIN: greg@sj.ate.slb.com Schlumberger Technologies UUCP: ...!uunet!sjsca4!greg 1601 Technology Drive BIX: gwage San Jose, CA 95110-1397 CIS: 74016,352 (408) 437-5198 GEnie: G.WAGEMAN ------------------ Opinions expressed herein are solely the responsibility of the author. (And the author wouldn't have it any other way.)
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ukma!xanth!lll-winken!uunet!snjsn1!bilbo!greg From: greg@bilbo (Greg Wageman) Newsgroups: sci.physics,sci.math,sci.electronics Subject: Re: noise cancellation Message-ID: <765@snjsn1.SJ.ATE.SLB.COM> Date: 22 Mar 89 00:21:21 GMT References: <723@wucs1.wustl.edu> <7260@fluke.COM> <453@corpane.UUCP> Sender: news@SJ.ATE.SLB.COM Reply-To: greg@sj.ate.slb.com (Greg Wageman) Organization: Schlumberger ATE, San Jose, CA Lines: 28