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From: gauss@hound.UUCP (E.GAUSS)
Newsgroups: rec.aviation,sci.electronics,rec.audio
Subject: Re: Noise-cancelling earphones
Message-ID: <2139@hound.UUCP>
Date: Tue, 26-May-87 14:22:15 EDT
Article-I.D.: hound.2139
Posted: Tue May 26 14:22:15 1987
Date-Received: Thu, 28-May-87 04:27:41 EDT
References: <1027@mips.UUCP> <1746@masscomp.UUCP>
Organization: AT&T Bell Laboratories, Holmdel
Lines: 16
Summary: Who makes one
Xref: mnetor rec.aviation:1691 sci.electronics:753 rec.audio:1742

In article <1746@masscomp.UUCP>, ahv@masscomp.UUCP (Tony Verhulst) writes:
> 
>  In article <1027@mips.UUCP> mark@mips.UUCP (Mark G. Johnson) writes:
>  >The new system puts a microphone in each earcup, and uses the resulting
>  >signal to measure the "error" at the pilot's ear [error == signal at ear
> 
> I understand that such a system was used on the Voyager flight and was 
> supposed to have prevented the crew from suffering permanent hearing
> impairment during their flight.

HIGH TECHNOLOGY, May 1987, pg 6 says:  Bose (Framingham, Mass) made the
system under Air Force funding.  25db reduction is achieved.  "Bose hopes
eventually to market the patented phones....".  It was used on the Voyager
and is being trialed by the military.  The system works below 1000 khz.

Ed Gauss, Fat Moose Flying Service, retired