[PD] spring modeling/scanned synthesis (was: trying to test 'pdp library and 'pdp_scan~')

Alexandre Torres Porres porres at gmail.com
Thu Feb 15 20:17:16 CET 2024

So, hi, allow me to add an answer from the SC forum
https://scsynth.org/t/spring-modeling/8977/8?u=porres this and the next
comment answers my question whether I can just use filters like [resonant~]
(based on SC's Ringz). Short answer: yes. Let me quote.

"Many types of second order bandpass filters are also calculated as one
feedforward term and two feedback terms, meaning that (at minimum) some
types of BPFs *are* spring-model resonators."


"The spring stuff is interesting for getting an idea of how filters work,
but the standard EQ filters are practical implementations of it, and you
can just use those"

Em qui., 15 de fev. de 2024 às 02:19, Alexandre Torres Porres <
porres at gmail.com> escreveu:

>  Em sáb., 27 de jan. de 2024 às 05:00, cyrille henry <ch at chnry.net>
> escreveu:
>>  Now let me see if I can get the main principal, is it like you have wave
>>> table points that move according to spring like motions when excited and
>>> evolving through time?
>> it's the masses that move!
>> if you want to understand more, look at :
>> http://www.chnry.net/ch/IMG/pdf/-2.pdf
> ok, the masses move, but they move according to a "spring like motion" as
> I said and each mass represents a point in a wave table, right? Also, you
> have a chain of masses and the last one (the last point in a table)
> connects back to the first one, huh?
> Anyway, just had some time to look back on this. And I've been checking
> some Spring-Mass-Systems.
>  I was checking the code of the Spring class in SuperCollider, I was able
> to port it to Pd. See
> https://github.com/supercollider/supercollider/blob/db7eed2a17c361503dbc7f70a557874b6001e3cd/server/plugins/PhysicalModelingUGens.cpp#L77
> note the code says
> *// some basic physical modeling ugens - julian rohrhuber 1/04// these are
> very simple implementations with cartoonification aspects.*
> And in fact, I was checking this other mass spring damper system
> implemented in Max (that I also ported to Pd) and it seems a much more
> robust system with more meaningful parameters based on actual physical
> quantities https://www.youtube.com/watch?v=2rFkZD51mT8
> How do both compare to pmpd? Is there any canonical model or it's one of
> those things that is a matter of taste and subject to things like desired
> efficiency versus realism? Do any of you know of more models out there in
> Pd or other computer music systems such as Csound, MAX, etc?
> I've also been having fun with Sine Waves with exponential decay
> envelopes. Like with the [decay~] object from ELSE which is like the Decay
> class in SC - a one pole filter that you set a "t60" decay time in ms (time
> it takes to decay 60dB). This way you have a good control on the frequency
> and decay time. Another option is to just [resonant~] from ELSE, which is
> also like SuperCollider's Ringz.ar, excited by impulses. This is a
> resonant 2nd order filter that "rings" for a given decay time and
> frequency. How does this compare to "Spring Models"? How is Spring
> "springer" than creating damped oscillators with [decay~] and [resonant~]?
> Also, for reference, I found this in Pd as well
> https://www.youtube.com/watch?v=zW7y5yb0YWQ that I am relating to
> [resonant~].
> Who's got more references?
> Cheers
> thanks
> Alex
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