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Path: utzoo!watmath!watdcsu!herbie
From: herbie@watdcsu.UUCP (Herb Chong [DCS])
Newsgroups: net.audio
Subject: Re: Copy protected records?
Message-ID: <944@watdcsu.UUCP>
Date: Mon, 11-Feb-85 14:51:27 EST
Article-I.D.: watdcsu.944
Posted: Mon Feb 11 14:51:27 1985
Date-Received: Tue, 12-Feb-85 04:50:49 EST
References: <305@boulder.UUCP>
Reply-To: herbie@watdcsu.UUCP (Herb Chong [DCS])
Distribution: net
Organization: U of Waterloo
Lines: 32
Summary: 

In article <305@boulder.UUCP> jon@boulder.UUCP (Jonathan Corbet) writes:
>[]
>
>	I have heard rumors from a couple of sources now that some record
>companies are adding a high frequency signal to their records that 
>interfere with the bias on tape decks, thus making it difficult to make
>tapes of said records.  Does anybody know if this is really true, and
>if so, just what the technique is?
>
>--
>Jonathan Corbet
>National Center for Atmospheric Research, Field Observing Facility
>{seismo|hplabs}!hao!boulder!jon

i think that this rumor is false.  most cartridges do not have enough
high frequency response to deliver such a signal at a sufficient level
to affect taping by overbiasing.  remember that about the minimum
acceptable frequency for bias is about 90kHz.  if the signal was
sufficiently high in level to be reasonably reproduced by the majority
of cartridges, almost all would not be a able to track it.  also, most
cutter heads do not reproduce past about 35kHz.  the CD-4 records that
required response to 50kHz were all half-speed mastered to get around
this problem.

Herb Chong...

I'm user-friendly -- I don't byte, I nybble....

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