yes, I saw that some time ago. Not much in the way of a mathematical description, though. ----- Original Message ----- From: Steven Yi Date: Wednesday, December 5, 2007 8:15 pm Subject: Re: [Cs-dev] New opcodes useful? To: Developer discussions > Hi Victor, > > I did find this wikipedia article just now: > > http://en.wikipedia.org/wiki/Phase_distortion_synthesis > > BTW: I'm looking very forward too trying these out Anthony! > > steven > > > > On Dec 5, 2007 11:54 AM, wrote: > > Do you know if there is any references on PD in the > > literature. Apart from the simple descriptions on Casio > > manuals, I never saw anything else. > > > > yes, the PD technique as I understand it does not seem > > to be bandlimited. But I wonder if there are any tricks > > that are not documented anywhere. > > > > Also do you know how to produce the resonant version > > of PD? That was an interesting sound. > > > > Interesting to see the classic topic of waveshaping being > > discussed, as well. In these days of fast computers, people > > seemed to forget about these great ways of economically > > synthesising complex spectra. > > > > Victor > > > > > > ----- Original Message ----- > > From: Anthony Kozar > > Date: Wednesday, December 5, 2007 7:40 pm > > Subject: Re: [Cs-dev] New opcodes useful? > > To: Csound Developer list > > > > > Well, if my intuitions are correct, using continuous k-rate > > > > > coefficientswith either the polynomial or chebyshevpoly opcodes > > > should produce smooth > > > and continuous changes in the output. I have tested the > > > latter by > > > controlling several harmonics independently and I got smooth > > > changes just as > > > if I had used additive synthesis with multiple > > > oscillators. I would be > > > interested to know if there is some mathematical problem > that I am > > > overlooking. > > > > > > Regarding the phase distortion opcodes: the reason I was > > > questioning their > > > utility is that they DO produce aliasing because the derivative > > > of the > > > resulting signal is discontinuous. I think -- but am not > > > sure -- that > > > Casio's original implementation of this technique was not 100% > > > digital. But > > > depending on the genre of music, aliasing is not always a bad > > > thing :) > > > > > > Another use for the PD opcodes is to use them on audio signals > > > instead of > > > phasors, in which case they behave as piecewise-linear transfer > > > functions.This also produces aliasing, but they have definite > > > applications as > > > alternative distortion techniques. powershape is also > > > excellent for > > > distortion, although it can produce milder, bandlimited > changes too. > > > > > > At least this is my understanding of everything -- I am not a > > > DSP guru ... > > > > > > Anthony Kozar > > > anthonykozar AT sbcglobal DOT net > > > http://anthonykozar.net/ > > > > > > > > > > Victor.Lazzarini@nuim.ie wrote on 12/5/07 4:00 AM: > > > > > > > > Interesting... I am wondering if radical changes tothe the > > > transfer function > > > > would cause discontinuities inthe output signal. Never thought > > > of the > > > > question. I'll love to try them. Coincidentally, I was only > > > > yesterdayteaching > > > > a class on waveshaping. > > > > > > >> Victor.Lazzarini@nuim.ie wrote on 12/5/07 2:54 AM: > > > >> > > > >>> PD seem useful. UDOs are also good because they're > > > didactical, can you > > > >>> do both? > > > >> > > > >> Thanks. I wrote the phase dist. opcodes (and powershape > > > below) a while ago > > > >> but I will make UDOs too. > > > >> > > > >>> How do the waveshaping opcodes you mention > > > >>> differ from simply building them with oscillator and table > > > >>> lookup? > > > >> > > > >> They allow for _dynamic_ waveshaping where the transfer > > > function varies over > > > >> time. I have written the following opcodes so far and > > > hope to come up with > > > >> some more: > > > >> > > > >> aout powershape ain, kShapeAmount [, > > > ifullscale]>> aout polynomial ain, ka0 > > > [, ka1 [, ka2 [...]]] > > > >> aout chebyshevpoly ain, ka0 [, ka1 [, ka2 [...]]] > > > > > > > > > ------------------------------------------------------------- > ---- > > > -------- > > > SF.Net email is sponsored by: The Future of Linux Business > White Paper > > > from Novell. From the desktop to the data center, > Linux is going > > > mainstream. Let it simplify your IT future. > > > http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 > > > _______________________________________________ > > > Csound-devel mailing list > > > Csound-devel@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/csound-devel > > > > --------------------------------------------------------------- > ---------- > > SF.Net email is sponsored by: The Future of Linux Business > White Paper > > from Novell. From the desktop to the data center, Linux > is going > > mainstream. Let it simplify your IT future. > > http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 > > _______________________________________________ > > Csound-devel mailing list > > Csound-devel@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/csound-devel > > > > ----------------------------------------------------------------- > -------- > SF.Net email is sponsored by: The Future of Linux Business White Paper > from Novell. From the desktop to the data center, Linux is going > mainstream. Let it simplify your IT future. > http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 > _______________________________________________ > Csound-devel mailing list > Csound-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/csound-devel ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Csound-devel mailing list Csound-devel@lists.sourceforge.net