Re: Adjust-Speed CD player?

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Article #363

#363

From: Jon W{tte
Date: Sun, 24 Sep 1989 10:42

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In article <4653@orca.WV.TEK.COM> mhorne%ka7axd.wv.tek.com@relay.cs.net writes:

>frequency scaling algorithm, perhaps by doing a digital mix with a reference
>(digital) carrier (i.e. ref = 100 Hz for a 100 Hz shift upward in frequency),
>followed by a carrier and lower sideband suppression (Hilbert transform filter
>are very easy to implement digitally).  At a fast glance, I think this might
>work well for moving the spectra of an audio source up/down some arbitrary
>frequency, and should be doable with some of the common DSP chips currently
>available.

As I've said before: that's not scaling, that's OFFSET ! You can't do that
to MUSIC, because music has a realative overtone spectra. Consider:

440 Hz + 880 Hz make a (very simple) harmonic note.

Shift 100 Hz:

540 + 940 Hz makes two sine notes !!! And imagine the effect this has on
complex waveforms like a violin or a piano ... SHUDDER !

h+@nada.kth.se
-- 
The only way to get rid of temptation is to yield to it.

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References: <61860@tut.cis.ohio-state.edu> <4653@orca.WV.TEK.COM>

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Path: arc1-ca.pugleaf.net!utzoo!attcan!uunet!bloom-beacon!eru!luth!sunic!draken!d88-jwa
From: d88-jwa@nada.kth.se (Jon W{tte)
Newsgroups: comp.dsp
Subject: Re: Adjust-Speed CD player?
Message-ID: <1752@draken.nada.kth.se>
Date: 24 Sep 89 10:42:03 GMT
References: <61860@tut.cis.ohio-state.edu> <4653@orca.WV.TEK.COM>
Reply-To: d88-jwa@nada.kth.se (Jon W{tte)
Organization: Royal Institute of Technology, Stockholm, Sweden
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