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From: dave@sdeggo.UUCP
Newsgroups: sci.electronics
Subject: Re: 3800 Hz notch filter [will] be used on CD masters
Message-ID: <67@sdeggo.UUCP>
Date: Sun, 7-Jun-87 13:32:20 EDT
Article-I.D.: sdeggo.67
Posted: Sun Jun  7 13:32:20 1987
Date-Received: Sun, 7-Jun-87 22:40:44 EDT
References: <598@neoucom.UUCP>
Organization: Lazy Programmer's Society of San Diego
Lines: 27
Keywords: with possible icky results!

In article <598@neoucom.UUCP>, wtm@neoucom.UUCP (Bill Mayhew) writes:
- The whole DAT spoiler seems silly to me.  The wost thing is that
- people who do not pirate the material are punished by having to
- listen to recordings of reduced quality.  It would be possible for
- pirates to go about their business by summing low level hiss with a
- spectrum centered at 3800 Hz.  I suppose that a correlation could
- be done to see if the amplitude of the 3800 component related to
- the sidebands, thus preventing hiss injection from spoiling the
- spoiler, but that sort of DSP would probably be too expensive for
- consumer equipment.

It sounds very silly, especially considering that those of us who buy CD's
are paying a premium for high sound quality.  Like any other form of copy 
protection, there are sure to be plenty of ways around it, making the only 
people truly affected by it the ones who are lawfully paying for it.

Instead of messing about with the audio signal, why not just reach in with
a soldering iron and clippers and tweak the chip out of the circuit, or
make it think that it always has some noise there with a little 3800 HZ
oscillator tied to its input.  How much do you want to bet that 
Radio-Electronics has an article "for experimental and educational purposes"
on how to do it within a month after they come out?

It's amazing what some clowns will come up with in the name of "protection."
Isn't it enough that they charge a rather ridiculous price for the music, 
without dreaming up ways to make it sound bad?

----
David L. Smith
sdcsvax!sdamos!sdeggo!dave, ihnp4!jack!man!sdeggo!dave, hp-sdd!crash!sdeggo!dave
sdeggo!dave@sdamos.ucsd.edu