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Article #1604

Re: My CD player is running slow! (!)

#1604
From: Ken Yap
Date: Tue, 05 Jun 1990 21:46
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|>> ...Pitch-shifting in the 
|>> digital domain is a fairly ugly computational process, usually handled by
|>> high-speed DSP chips.  
|>
|>This is wrong.  Pitch shifting is easy.  My first CD player was an
|>inexpensive one and it had a pitch adjustment control on it.  It's my
|>guess that you can pitch shift just by changing the rate at which you
|>feed samples to the DtoA convertor. 
|
|This is wrong. Pitch shifting by spinning a CD faster is impossible. If anythingit would only play the music faster, but at the same pitch.
|If your CD player did pitch shifting, it could only have done it at the
|analogue output stage, unless it had the appropriate DSP hardware in it, which
|I doubt.

Nope you're wrong. There was a project in Elektor to add pitch
shifting to a particular line of CD players by altering the master
clock, i.e.  replace the crystal with an externally generated clock.
So everything goes faster, including the drive motor, when you crank up
the clock. Mind you, I'm not saying this is possible on every CD
player. And I definitely think the original poster's CD player is spot
on frequency-wise.
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Message-ID: <1990Jun5.214603.9741@cs.rochester.edu>
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!rutgers!rochester!ken
References: <1990Jun2.182334.21396@athena.mit.edu> <6378.26693284@umiami.miami.edu> <55024@microsoft.UUCP> <89@rhum.tcom.stc.co.uk>

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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!rutgers!rochester!ken
From: ken@cs.rochester.edu (Ken Yap)
Newsgroups: rec.audio,sci.electronics
Subject: Re: My CD player is running slow! (!)
Message-ID: <1990Jun5.214603.9741@cs.rochester.edu>
Date: 5 Jun 90 21:46:03 GMT
References: <1990Jun2.182334.21396@athena.mit.edu> <6378.26693284@umiami.miami.edu> <55024@microsoft.UUCP> <89@rhum.tcom.stc.co.uk>
Reply-To: ken@cs.rochester.edu
Organization: University of Rochester Computer Science Dept
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Address: Rochester, NY 14627, (716) 275-1448