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From: du4@mace.cc.purdue.edu (Ted Goldstein)
Newsgroups: sci.physics,sci.electronics
Subject: Re: noise cancellation
Message-ID: <2283@mace.cc.purdue.edu>
Date: 25 Apr 89 14:59:03 GMT
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Reply-To: du4@mace.cc.purdue.edu (Ted Goldstein)
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In article <17419@cup.portal.com> ISW@cup.portal.com (Isaac S Wingfield) writes:
>Well, there's been a lot of talk about automobile engine noise
>cancellation, using some kind of "active muffler".

All this talk about cancelling the muffler noise of a car has reminded me
of a study of highway noise I once read (sorry I don't remember where).
The conclusion they arrived at was that most noise coming from 
a highway is from car TIRES on the road surafce, and not engine noise.