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From: jphalter@ihuxb.UUCP
Newsgroups: net.audio
Subject: Impulse Noise Reducers
Message-ID: <374@ihuxb.UUCP>
Date: Fri, 7-Oct-83 18:58:48 EDT
Article-I.D.: ihuxb.374
Posted: Fri Oct  7 18:58:48 1983
Date-Received: Sun, 9-Oct-83 09:09:56 EDT
Organization: AT&T Bell Labs, Naperville, Il
Lines: 23

In response to information requests about impulse noise reduction units, 
I can say the following:
      
        (1) These gadgets have been around for a while. A few (4-5?) years
            ago SAE, Garrard, and Burwen were all marketing various impulse
            noise reducers. The only unit I've seen recently is the Burwen.

        (2) All three of the above units attempt to detect audio signals
            with both very fast rise times and very fast fall times (such
            as a record tick). Once such an occurance has been detected,
            the gadget mutes the output for a few milliseconds. The mute
            is supposed to be so brief that it is essentially inaudible
            but long enough to eliminate the offending tick.

        (3) I remember a review of the Burwen and SAE boxes from an audio
            magazine a few years ago. In summary, they found the Burwen
            to be superior at tick removal because this unit muted the
            output for a non-fixed duration based on the width of the tick.
            The SAE had a fixed mute window that ostensibly was less effective
            at inaudibly removing the tick.

        (4) The Burwen was about $250-300 and the SAE was about $200 in 
            1978-79?.