It doesn't seem to output a steady pulse either (see attached patch - then again i hope i got you). Maybe it doesn't really matter. I can try with my guitar right now. Out of curiosity, what kind of resonator can i use? I only know resonant filters (like the moog~ bp filter) and karplus-strong resonators. Thanks again for your help. (I think i've been forgetting to reply to the list...)
2010/9/30 Pierre Massat <pimas...@gmail.com> > So basically, i get a square wave. Then i use the rzero filter with a > parameter set to 1, so that i get X(n)-X(n-1), which is equal to 0 all over > the flat sections of the wave (except for the first sample), and equal to > Delta (or something) or -Delta at the points where is rises and falls. If i > clip this again between 0 and 1, i get a pulse everytime the wave rises from > -1 to 1. Am i wrong? I have never used such a filter... > Thank you! > > Pierre > > 2010/9/30 Andy Farnell <padawa...@obiwannabe.co.uk> > > >> >> >> Yeah its a bitch actually because in Pd >> the blocksize sets an effective resolution >> for events. You could ask on-list about >> tricks with blocksize, Frank might have >> a solution. >> >> >> I'll share a couple of DSP tricks wit you >> as used in guitar subharmonic processors, >> if you don't mind keeping it all in the audio >> domain (which can be more tricky) >> >> Firstly you amplify by about 100 and clip >> the signal >> >> [*~ 100] >> | >> [clip~ -1 1] >> >> this gives you basically a square wave >> >> Next differentiate using a [rzero~] >> so that you get a series of pulses. >> >> Rectify them by clipping again [clip~ 0 1] >> >> Use these pulses to drive into a bank of >> parallel resonators for the rattle effect. >> >> cheers, >> >> Andy >> >> >> >> >> >> >> >> >> >> >> On Thu, 30 Sep 2010 20:15:15 +0200 >> Pierre Massat <pimas...@gmail.com> wrote: >> >> > Ok, i think i get it. >> > I've tried do make a simple zero-crossing detection patch using >> threshold~, >> > but it doesn't seem to really work. From what i've read here and there >> about >> > zero crossing in Pd it seems like the size of audio blocks is an issue >> here. >> > Using a simple osc~ as a sound generator and a threshold~ set to 0 0 0 >> 0, i >> > get a fairly steady bang at very low frequencies, but it gets extremely >> > messy for frequencies above 10 Hz or so. >> > I ve tried reducing the block size in the subpatch where threshold~ is, >> to >> > no avail. >> > I haven't found anything that properly deals with zero crossing >> detection in >> > Pd. So i'm kinda stuck! >> > >> > Pierre >> > >> > 2010/9/29 Andy Farnell <padawa...@obiwannabe.co.uk> >> > >> > > On Wed, 29 Sep 2010 08:42:28 +0200 >> > > Pierre Massat <pimas...@gmail.com> wrote: >> > > >> > > > Hi Andy, >> > > > Are you talking about something like that: >> > > > http://www.complexity.org.au/ci/vol01/fletch01/html/ >> > > >> > > Not quite. THis is very interesting (I've bookmarked it >> > > for future reading) but deals with non-linearity >> > > in a continuous equation. >> > > >> > > For rattling, we are interested in dis-continuous >> > > coupling. >> > > >> > > >> > > > I m not familiar with zero crossing detection at all. From what i ve >> read >> > > in >> > > > the archives it seems to be possible to do it with edge~. >> > > >> > > If you search you will find other ways using snapshot~ and threshold~ >> > > too. >> > > >> > > > So i'd need to >> > > > trigger something like a pulsed noise everytime it detects a zero? >> That'd >> > > be >> > > > the trick? >> > > >> > > Yes, basically drive another synth that makes a pulse or resonant >> click >> > > every time the string crosses zero. >> > > >> > > > Thanks again for your help! >> > > > >> > > > Pierre >> > > > >> > > > 2010/9/28 Andy Farnell <padawa...@obiwannabe.co.uk> >> > > > >> > > > > >> > > > > >> > > > > Aha! This is a different problem. It's about creating >> > > > > a discontinuity such that the string excursion seems to >> > > > > cause a point of new impact in a different system. >> > > > > >> > > > > >> > > > > The traditional way is to do zero crossing detection >> > > > > and use that to trigger some other sound. >> > > > > >> > > > > best, >> > > > > Andy >> > > > > >> > > > > On Tue, 28 Sep 2010 13:07:49 +0200 >> > > > > Pierre Massat <pimas...@gmail.com> wrote: >> > > > > >> > > > > > So i'm really only interested in modeling the rattling sound, >> the >> > > buzz, >> > > > > to >> > > > > > get a dirtier sound, like in most african instruments. I don't >> know >> > > if >> > > > > > you've ever played a guitar with a strip a paper kind of weaved >> > > accross >> > > > > the >> > > > > >> > > > > -- >> > > > > Andy Farnell <padawa...@obiwannabe.co.uk> >> > > > > >> > > >> > > >> > > -- >> > > Andy Farnell <padawa...@obiwannabe.co.uk> >> > > >> >> >> -- >> Andy Farnell <padawa...@obiwannabe.co.uk> >> > >
rzero_pulse.pd
Description: Binary data
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