Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!wuarchive!gem.mps.ohio-state.edu!ginosko!uunet!zephyr.ens.tek.com!orca!ka7axd.wv.tek.com From: mhorne@ka7axd.wv.tek.com (Michael T. Horne) Newsgroups: comp.dsp Subject: Re: Adjust-Speed CD player? Message-ID: <4671@orca.WV.TEK.COM> Date: 25 Sep 89 05:35:52 GMT References: <61860@tut.cis.ohio-state.edu> <4653@orca.WV.TEK.COM> <1752@draken.nada.kth.se> Sender: nobody@orca.WV.TEK.COM Reply-To: mhorne%ka7axd.wv.tek.com@relay.cs.net Organization: Tektronix, Inc., Wilsonville, OR Lines: 28 In a recent article by d88-jwa@nada.kth.se (Jon W{tte): >>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... > >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. Ah. Having arrived at this discussion in mid stream (without the benefit of context), I believe that the question is about scaling an arbitrary `musical' (from the viewpoint of the average person) sequence up or down in frequency while retaining the `musical-ness' of it. :) I still stand by my suggestion of shifting an arbitrary spectrum up/down in frequency by doing a digital mix, however, I agree that it will not generate the desired effect for use in scaling music. It would appear that the `vocoder' method may provide arbitrary control (e.g. true (multiplicative) scaling) for generating such desired effects. >And imagine the effect this has on complex waveforms like a violin or a >piano... Could you please elaborate on the typical spectra of a given note on a piano or violin? Mike Michael T. Horne VSG/ITD, Tektronix, Inc. mhorne@ka7axd.wv.tek.com (503) 685-2077