Hardware Physical Modelling


I’m on it!

Thank you @ Foxhood. That’s a great link. I do whatever comes to mind, but having a path to follow leads to interesting experiments, especially if you spend time trying to figure out why some components of a patch work the way they do.


sounds great, very interesting!

i don’t ask… but…

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Sounds really interesting, mind posting a sound clip ;)?

My interest in modelling is not to reproduce real instruments but to try and replicate some of the physical events that help produce those sounds and transform my “imaginary sound world”, into something more corporeal or lifelike. I see it as converting signal into matter.


That design could suit inferior, automated mass production to satisfy consumer demand, but that is not in the immediate future.

For now it’s interesting to consider the technique, which interestingly has not been solved in the digital (audio) domain. I’m not sure of the mathematical derivation of waveguide as an analog to the wave equation in 2 dimensions (i.e. vibrating string), but it certainly sounds very different to my ears, and it’s nice to find that analog computation is far from obsolete. Digital techniques in solving PDEs are computationally heavy, using elaborate variations on finite difference method, but the resolution of analog integrators is unrivalled, something which the humanoid has endless affection for.

Will be moving to physical prototyping soon, as mentioned before will get some audio demos out.


thanks, please post the audio demos here, very interested in this design!
i believe the mungo p0 percussion module does modell a circular membrane…not entirely sure about that anymore.


Patch notes are in the SoundCloud description.

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Has anyone tried the CG products Delay 1022? How does it compared to the mungo d0 for modelling?

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If you had to choose between the Mungo c0 and the d0 for these purposes, which one would you choose? It’s rather obvious that short delays are essential but I’m uncertain if the c0’s BBD is up to the task or if d0 is the safest choice.

Opinions are welcome.


Still lacking an interesting noise source in my rack, I’ve been looking at the CG Products Noise VCA, but can’t find a supplier in the USA that carries it. It looks perfect for using as an exciter though: noise, resonant multimode filter, and VCA all in one with some clever routing options. Is anybody here working with one of these?


No but I’ve been looking at the Delay1022 Mk2 as a nice delay option instead of the Mungo. Seems that both modules have modeling as their design inspiration .


with short delay times, karplus strong etc the difference doesn’t matter, the c0 is great for that too, only when the delay times get longer the bbd emulation filters the thing down quite a bit.

the cg products delay is great, it has an internal lpf which helps reduce the high frequency noise (i guess clock noise?), so the sounds get a bit muffled, great for bassy string sounds etc.
all his products are great, love the peak&hold, the ring modulator, now i get the oscillator and i am thinking of getting his noise vca too. it seems that he designs his modules with percussion or percussive sounds in mind. his own instruments look fun and interesting, i guess the circuits from the modules are all integrated in these fantastic looking instruments!:


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Am I right to assume that I could use one of the outputs being fed back to Input 1 (with the on-board attenuation) as a Feedback path ? As it was suggested earlier in this thread Delay > Filter > Delay gives really nice results.

I have to say that the CG Products UI is inviting. It has the old-school precision test equipment vibe which seems perfect when you’re doing physical modeling.


there are three different feedback paths with a corresponding switch, up is normal positive feedback internally routed, controlled by feedback knob. middle position is “open”, that’s the one you want if external filters etc should be used, you take the signal from delay out and then use the second input. third position is inverted feedback again internally routed.

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the cg delay is really great, imo the best analog bbd delay in eurorack, although the doepfer ones are cool too. but you can’t really compare to the mungo, the digital delay is so much cleaner and more versatile for such patches.

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From first perspective I would’ve guessed that the CG Delay is more suited to the task. But knowing Mungo, I can imagine that a digital BBD would be noiseless (no high frequency) and could go into very extreme places. That being said, I’m still very curious to try the CG. It lools inviting and seems designed for the purpose. It’s also readily available in EU and cheaper.

Since the earlier patch suggestion would have it set at thr highest rate possible and have a filter do the pitch division, I’d like to believe the high frequency of the BBD wouldn’t be intrusive.


Here’s a weird question: how important is distortion? I’ve been listening to some Geiger Counter demos, and contrary to reason, I hear some sounds in there that could be useful to provide some dimensionality to the sound. Some crackle. Without becoming too digital or too broken.

Is that covered by the feedback system already?
Opinions are welcome.


Geiger Counter is a pretty flexible waveshaper. I had the pedal version and would have kept it if not for the ER-301’s sample scanner unit (though I need to find a consistent way to stop it from wrapping around when the start and end points are discontinuous). I can see how it would enhance anything involving feedback loops.

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I wouldn’t say it’s necessarily important. But it’s certainly fun and will give you new sounds that you might end up liking. I recorded this audio last week of an electric guitar patch using the Disting’s triangle-to-sine shaper as a subtle distortion in the feedback loop and it really made the sound come alive.


It’s a different sort of distortion from the geiger counter though, of course. I think the Geiger would be great for percussive patches with its dirty digital style.

The main thing to keep in mind is most distortion will quickly cause a feedback loop to become uncontrollable mush, and a little bit goes a loooong way. In the patch above, I had the Disting’s gain up just barely enough to introduce distortion, so low that if it weren’t in a feedback loop compounding on itself, it would probably just sound like a dry signal. If you’re working with a harsher distorter that doesn’t have a wet/dry control, you might need to split the path and mix your own dry/wet balance. That’s one of the best ways I’ve found to deal with runaway distorted feedback.

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I was afraid that would be the case. I owned the module years ago, but I’m not a big fan of bitcrushing etc, so I sold it. A friend decided to sell his and I checked the DivKid video to refresh my memory and I have to say that I like the timbers that the waves impose on the incoming signal. Someone said they used it in feedback patches, and after second consideration I now know they meant creating noise out of it, but it clicked “what if I had it on my physical modeling case to add some extra dimension after the feedback?”.

I have to give it a try I guess.

[quote=“smbols, post:140, topic:17740”]
The main thing to keep in mind is most distortion will quickly cause a feedback loop to become uncontrollable mush, and a little bit goes a loooong way. [/quote]

Thanks for the pointers. I’ll try using the Geiger Counter’s two inputs to see how it feedbacks, but I’ll mainly conceptualize this as a filtering device, to be added on the feedback path or after the feedback. In either case, I have a bunch of mixers there to create feedback loops and tame in how much each element gets a say in the structure. I’ll report back with my findings.


i like wavefolders inside the feedback, especially a dc offset there can change the sound alot, for flute sounds this is really cool.

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