Maybe also this could be of interest: http://puredata.hurleur.com/sujet-2453-cubic-soft-clip-distortion
Mathieu 2010/9/12 <[email protected]> > Send Pd-list mailing list submissions to > [email protected] > > To subscribe or unsubscribe via the World Wide Web, visit > http://lists.puredata.info/listinfo/pd-list > or, via email, send a message with subject or body 'help' to > [email protected] > > You can reach the person managing the list at > [email protected] > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Pd-list digest..." > > Today's Topics: > > 1. Re: Guitar distortion (Chebyshev?) (Mathieu Bouchard) > 2. Re: Guitar distortion (Chebyshev?) (Mathieu Bouchard) > 3. Re: puredata.info wiki structured text format? > (Hans-Christoph Steiner) > 4. Re: Guitar distortion (Chebyshev?) (Martin Peach) > 5. Re: Pd-extended 0.42.5 release candidate 6 released! > (Hans-Christoph Steiner) > 6. Re: Guitar distortion (Chebyshev?) (Mathieu Bouchard) > 7. Re: Guitar distortion (Chebyshev?) (Kim Cascone) > 8. Re: Guitar distortion (Chebyshev?) (Martin Peach) > > > ---------- Messaggio inoltrato ---------- > From: Mathieu Bouchard <[email protected]> > To: Pierre Massat <[email protected]> > Date: Sun, 12 Sep 2010 11:07:29 -0400 (EDT) > Subject: Re: [PD] Guitar distortion (Chebyshev?) > On Sun, 12 Sep 2010, Pierre Massat wrote: > > One issue is that it seems to sound good only when the amplitude of the >> sound is close to 1, which is obviously not the case for a raw guitar sound. >> > > Tu peux utiliser la version polynômiale des formules de Tchébycheff, car > celles-ci s'étendent au delà de 1 sans problème, tandis que la version > arccosinus a des problèmes en dehors de l'intervalle -1..+1 (pour simplifier > les choses, on dit habituellement qu'elle n'existe pas en dehors de cet > intervalle...). > > Mais c'est quand même mieux de pas tellement dépasser ±1, c'est juste que > les polynômes pardonnent beaucoup plus. C'est un effet très dépendant du > volume. > > _______________________________________________________________________ > | Mathieu Bouchard ------------------------------ Villeray, Montréal, QC > > ---------- Messaggio inoltrato ---------- > From: Mathieu Bouchard <[email protected]> > To: Pierre Massat <[email protected]> > Date: Sun, 12 Sep 2010 11:13:55 -0400 (EDT) > Subject: Re: [PD] Guitar distortion (Chebyshev?) > On Sun, 12 Sep 2010, Pierre Massat wrote: > > I m not trying to model an amp here, i m only interested in modeling a >> distortion unit. >> > > Ah, I forgot, did you try [expr~ tanh($v1)] ? > > At first I assumed that you wanted to go beyond that simple distorsion and > into more interesting forms of distortion. Chebyshev's are only useful if > you want something that can also sounds like pitch shifts by harmonic steps. > > I think that tanh is rather close to the physical behaviour of capacitors > being strained, but surely not exactly that, and I didn't do the math to > figure out what the real formula would be. (Did anyone try that ?) > > _______________________________________________________________________ > | Mathieu Bouchard ------------------------------ Villeray, Montréal, QC > > ---------- Messaggio inoltrato ---------- > From: Hans-Christoph Steiner <[email protected]> > To: "João Pais" <[email protected]> > Date: Sun, 12 Sep 2010 11:29:51 -0400 > Subject: Re: [PD] puredata.info wiki structured text format? > > On Sep 12, 2010, at 4:14 AM, João Pais wrote: > > I personally loathe the stucturedText format. I find it very difficult >>> to make it work. I use the MoinMoin syntax whenever I create a page on >>> puredata.info. >>> >> >> is there a reference link for that as well? >> >> I didn't said, but I'm asking this because I wanted to put in an excel >> chart. usually I use normal html. >> > > > http://wiki.winehq.org/SyntaxReference > > .hc > > > > ---------------------------------------------------------------------------- > > Terrorism is not an enemy. It cannot be defeated. It's a tactic. It's > about as sensible to say we declare war on night attacks and expect we're > going to win that war. We're not going to win the war on terrorism. > - retired U.S. Army general, William Odom > > > > > > > ---------- Messaggio inoltrato ---------- > From: Martin Peach <[email protected]> > To: Mathieu Bouchard <[email protected]> > Date: Sun, 12 Sep 2010 11:32:41 -0400 > Subject: Re: [PD] Guitar distortion (Chebyshev?) > On 2010-09-12 11:13, Mathieu Bouchard wrote: > >> On Sun, 12 Sep 2010, Pierre Massat wrote: >> >> I m not trying to model an amp here, i m only interested in modeling a >>> distortion unit. >>> >> >> Ah, I forgot, did you try [expr~ tanh($v1)] ? >> >> At first I assumed that you wanted to go beyond that simple distorsion >> and into more interesting forms of distortion. Chebyshev's are only >> useful if you want something that can also sounds like pitch shifts by >> harmonic steps. >> >> I think that tanh is rather close to the physical behaviour of >> capacitors being strained, but surely not exactly that, and I didn't do >> the math to figure out what the real formula would be. (Did anyone try >> that ?) >> >> > See attached patch. I use it instead of a fuzz box now. > It's not the capacitors, it's the amplifier losing gain when it approaches > the power supply. Vacuum tubes have a softer knee than transistors. > > > Martin > > > ---------- Messaggio inoltrato ---------- > From: Hans-Christoph Steiner <[email protected]> > To: "João Pais" <[email protected]> > Date: Sun, 12 Sep 2010 12:03:25 -0400 > Subject: Re: [PD] Pd-extended 0.42.5 release candidate 6 released! > > On Sep 12, 2010, at 4:14 AM, João Pais wrote: > > a couple of my abstractions aren't packaged with this distribution, e.g. >>>> bezier.pd (it's in >>>> >>>> https://pure-data.svn.sourceforge.net/svnroot/pure-data/trunk/abstractions/jmmmp/ >>>> ). >>>> >>> >>> Yes, once the release process has started, then Pd-extended is built out >>> of a branch in SVN and not trunk. You can either check in the changes >>> yourself, or tell me what to check in. >>> >> >> you mean there are 2 places where we should submit the code? is there a >> wiki page with the instructions for it? >> > > When making a release, we work out of a branch so that only expected > changes get incorporated into the release. > > I would prefer to do it myself, then I don't have to ask you again next >> time about it :) >> >> João >> > > The current Pd-extended release branch is here: > > svn co > https://pure-data.svn.sourceforge.net/svnroot/pure-data/branches/pd-extended/0.42 > > There are some basic instructions here, basically you want to do an SVN > merge from trunk into a branch: > > http://puredata.info/docs/developer/GettingIntoPdextended > > some instructions: > > http://www.google.com/webhp?hl=en#sclient=psy&hl=en&site=webhp&q=svn+merge+trunk+into+branch&aq=f&aqi=g-c1g-o1&aql=&oq=&gs_rfai=&pbx=1&fp=ab5cdb1806fef4aa > > .hc > > > ---------------------------------------------------------------------------- > > Programs should be written for people to read, and only incidentally for > machines to execute. > - from Structure and Interpretation of Computer Programs > > > > > > ---------- Messaggio inoltrato ---------- > From: Mathieu Bouchard <[email protected]> > To: Martin Peach <[email protected]> > Date: Sun, 12 Sep 2010 12:05:30 -0400 (EDT) > Subject: Re: [PD] Guitar distortion (Chebyshev?) > On Sun, 12 Sep 2010, Martin Peach wrote: > > It's not the capacitors, it's the amplifier losing gain when it approaches >> the power supply. >> > > Yeah, but it seems to be a pattern similar to the one found in capacitors, > because capacitor theory has exp(-x) all over it, and the only way that > capacitors behave like [hip~] is when the signal is much below the capacity > rating (µF)... otherwise they lose gain... when they don't, it's because > exp(-x) can be well approximated by x. > > And then, exp is very close to tanh in several different ways, one of them > being this (use gnuplot) : > > plot [-2:2] [-1:1] exp(x*sqrt(2))-1, 1-exp(-x*sqrt(2)), tanh(x), x > > I put the plain 'x' at the end to show what I mean above (though you > already know that) > > _______________________________________________________________________ > | Mathieu Bouchard ------------------------------ Villeray, Montréal, QC > > ---------- Messaggio inoltrato ---------- > From: Kim Cascone <[email protected]> > To: [email protected] > Date: Sun, 12 Sep 2010 10:22:59 -0700 > Subject: Re: [PD] Guitar distortion (Chebyshev?) > couldn't locate the Smeck.pd download on the link posted for Miller's page > but here is the direct link in case you couldn't find it: > http://crca.ucsd.edu/~msp/smeck/latest/smeck-01.zip<http://crca.ucsd.edu/%7Emsp/smeck/latest/smeck-01.zip> > > > > > ---------- Messaggio inoltrato ---------- > From: Martin Peach <[email protected]> > To: Mathieu Bouchard <[email protected]> > Date: Sun, 12 Sep 2010 13:24:57 -0400 > Subject: Re: [PD] Guitar distortion (Chebyshev?) > On 2010-09-12 12:05, Mathieu Bouchard wrote: > >> On Sun, 12 Sep 2010, Martin Peach wrote: >> >> It's not the capacitors, it's the amplifier losing gain when it >>> approaches the power supply. >>> >> >> Yeah, but it seems to be a pattern similar to the one found in >> capacitors, because capacitor theory has exp(-x) all over it, and the >> only way that capacitors behave like [hip~] is when the signal is much >> below the capacity rating (µF)... otherwise they lose gain... when they >> don't, it's because exp(-x) can be well approximated by x. >> >> > I guess it's similar since capacitors charge at a rate proportional to a > voltage difference, while transistors can supply charge carriers at a rate > proportional to a voltage difference, so caps charge fastest when they are > nearly empty and transistors have the best gain with small signal inputs. > > The whole universe has exp written all over it in fact... > > And then, exp is very close to tanh in several different ways, one of >> them being this (use gnuplot) : >> >> plot [-2:2] [-1:1] exp(x*sqrt(2))-1, 1-exp(-x*sqrt(2)), tanh(x), x >> >> I put the plain 'x' at the end to show what I mean above (though you >> already know that) >> >> > Of course, all the hyperbolic trig functions are made from exp, by > definition. > > http://en.wikipedia.org/wiki/Hyperbolic_function > > Another use of exp is the sigmoid function used in biology, that can be > used to make a soft transition from one state to another as in 'fuzzy > logic'. > > Martin > > _______________________________________________ > Pd-list mailing list > [email protected] > to manage your subscription (including un-subscription) see > http://lists.puredata.info/listinfo/pd-list > >
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