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From: ISW@cup.portal.com (Isaac S Wingfield)
Newsgroups: sci.physics,sci.electronics
Subject: Re: noise cancellation
Message-ID: <17419@cup.portal.com>
Date: 20 Apr 89 20:12:03 GMT
References: <723@wucs1.wustl.edu> <7260@fluke.COM> <453@corpane.UUCP> <739@wucs1.wustl.edu> <20031@srcsip.UUCP> <859@prlhp1.prl.philips.co.uk> <482@atlas.tegra.UUCP>
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Well, there's been a lot of talk about automobile engine noise
cancellation, using some kind of "active muffler".

The first thing that occurs to me (and I don't know, even
approximately) is HOW MUCH ACOUSTIC POWER ARE WE TALKING ABOUT?
Because it'll take pretty much exactly the same amount of "negative
power" to make it go away.

I bet it's lots of watts, and if you think even *one* acoustic
watt isn,t that much, then you've never heard that much coming
from a Hi-Fi (especially at low frequency).

Isaac     isw@cup.portal.com