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From: srmjr@cbnewsd.att.com (samuel.r.mullins)
Newsgroups: comp.music
Subject: Re: Time change without pitch change
Message-ID: <1990Jul10.164035.516@cbnewsd.att.com>
Date: 10 Jul 90 16:40:35 GMT
References: <31559@cup.portal.com> <1990Jul9.173145.5808@funet.fi> <1306@fs1.ee.ubc.ca>
Organization: AT&T Bell Laboratories
Lines: 20

There is a wealth of literature concerning DSP algorithms for Time-Scale
Modification of speech.  I can't say for sure but I would guess
that some of the algorithms would not work well on music.  Anyway for
a representative sample of articles see Part Four of:

Speech Enhancement, Edited by Jae S. Lim, Prentice-Hall Signal Processing
Series, 1983.  ISBN 0-13-829705-3

In particular, the algorithm (based on modification of the Short-Time
Fourier Transform) presented by M. R. Portnoff gives very 
high quality results (at least for speech.)  

If you're not comfortable with DSP, don't bother (mostly IEEE Journal 
articles)

Sam Mullins
-- 
"What a strange, strange boy.  He sees the cars as sets of waves.
	Sequences of mass and space.  He sees the damage in my face."
				- Joni Mitchell