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From: lfoard@wpi.wpi.edu (Lawrence C Foard)
Newsgroups: sci.physics,sci.math,sci.electronics
Subject: Re: noise cancellation
Keywords: anti-noise
Message-ID: <1290@wpi.wpi.edu>
Date: 12 Mar 89 04:48:27 GMT
References: <723@wucs1.wustl.edu> <7260@fluke.COM>
Reply-To: lfoard@wpi.wpi.edu (Lawrence C Foard)
Organization: Worcester Polytechnic Institute, Worcester, MA. USA
Lines: 24

In article <7260@fluke.COM> inc@tc.fluke.COM (Gary Benson) writes:
>...
>The idea behind "anti-noise" as you call it is that you generate an exact
>replica of the offending noise, except opposite in polarity. It must be the
>same frequency and the same amplitude, just reversed. As the tops of the
>wave fronts collide, they dissipate each other's energy, and the same thing
>...

I think that inorder to make this work over a large area you would need to
completely surround the area with speakers and have a massive computer system
to figure out how to get the correct cancellation. But headphones would
probably work very well. Interesting things could be done like taking out an
annoying range of frequencys while allowing voice through (this would be nice
with the old VT52's). If you really wanted to get sick you could rearange the
sound to make voices come from different places. It would be pretty neat to
have a walkman type thing with an EQ on it and have the ability to knock out
or boost certain frequencys. I wonder if there is any market for this??

There where several messages that I have tried to reply to recently that our
system barfed on, one was a request for the full Guassian Quadrature routine,
is there another address I can try sending it to?
-- 
Disclaimer: My school does not share my views about FORTRAN.
            FORTRAN does not share my views about my school.