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Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!houxm!hound!rfg
From: rfg@hound.UUCP (R.GRANTGES)
Newsgroups: net.analog,net.audio
Subject: Re: Practical application for frequency shifter
Message-ID: <753@hound.UUCP>
Date: Tue, 27-Nov-84 12:41:15 EST
Article-I.D.: hound.753
Posted: Tue Nov 27 12:41:15 1984
Date-Received: Wed, 28-Nov-84 03:45:17 EST
References: <49@vax2.fluke.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
Lines: 15

[.]
If you can lock the oscillator to around 2hz, you will have reinvented a
feedback preventer for public address systems and your local whatever
will love you. With your device in the circuit, the amplified version
of your voice will still sound pretty much like you normally would, but
any feedback from speakers to mike will be frequency shifted so the
system cannot sing. You can then add more gain so speakers are louder
and audience can hear more easily.  I believem that you can't use a whole
lot more gain because then the recirculated version(s) of speech become
audible as a very peculiar sound. This is much less of a good idea on
music than voice, I understand. As should be obvious by now, I am not
aware of ever having heard one of these and the fact that they have not taken 
over the world indicates there is something wrong with the idea. However,
I do know these have been built and used fairly extensively.