I believe I successfully implemented the following in VCV rack. The oscillator rise and fall rates are constant, but the oscillator frequency changes by modulating the lower and upper bounds of the oscillation.
I found I needed to use a windowed comparator (comparator with a tolerance factor). My implementation produces an ascending ramp wave. The Thru module introduces some sample delays. I empirically found the sample delay count that required the smallest tolerance factor possible.
I used an extra comparator to allow for the bounding oscillators to switch places as to which is the min boundary and which is the max. The purple cables from the 2nd WinComp are just a wacky way of supplying a constant 10V signal to offset the fall time to the minimum supported value so that when switching the slew source to the min input for one sample the output instantly reaches that min value. I didn’t feel like adding an additional module for the constant CV.
I believe Peter’s Bound/Bounce oscillators can produce bounded triangle waveforms. I tried to emulate this in VCV, but it was not stable. I am thinking of creating one or more Venom modules that will do this. Perhaps some variation of Peter’s Fourses and/or Swoop modules.
Great Dave!
No I never got it to work properly –I was trying it with a triangle wave and having a symmetry/skew control on it. But I got distracted and left it –occasionally revisiting it with experiments, but no big things really. Excited to see where this will lead you!
A bit more hardware oriented, but this is also a very insightfull read on the concept, written by the same Richard Brewster (aka Pugix):
He analyzes and reconstructs an old schematic of a predecessor of the wonderful Sidrax Organ by Peter Blasser/Ciat Lonbarde and gives an interesting insight on the bounds modulation on it. Maybe it will inspire you.
In my excitement, I want to share this excellent resource of the bounce/bound concept as used by Peter Blasser. It is in the users guide of the Sidrax, written by Josh Singer (ieat31415).
On page 5 and 6 he explains it really well.
Edit: I do not know for sure if the link above works, but you can find the same document here:
Thanks! I imagine it will take time to digest all that. Based on a quick scan it looks like it will be easier to understand then Peter’s impenetrable writing style. I hope it can give me insight as to what happens if the lower bound exceeds the upper bound. For my patch I used a comparator with min/max outputs to switch the roles as needed. But the little I have read from Peter implies his creations have some other behavior that I do not understand.
The last link I shared (Josh Singer) is explaining it in more common math.
But yeah, Peter’s writings are enigmatic on purpose –once you get to know his instruments better, they start to make sense more and more. But for a start it surely is not an easy read.
