Path: 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 Lines: 23 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.