Sequentially Crossfade through poly channels

Hello everyone! Just getting into VCV here and having a lot of fun so far :slight_smile: Got a question about a particular thing I wanna achieve.

Let’s say I have a VCO and I want to change the output frequency by harmonic-series ratios meaning double the frequency, then triple, then quadruple etc etc.

I have worked out a number of ways to do that discretely, meaning insta-hop from one frequency to the next, but now I’m trying to find a way to smoothly crossfade from one frequency the next, in sequence.

This obviously requires a poly VCO, and I’ve found a way to process v/oct CV such that the VCO gets the fundamental frequency on the first channel then the second, third, fourth etc harmonic on suebsequent channels.

(In related news, with this setup any poly VCO becomes an additive synth which is pretty sick in its own right, but not what I was going for hihi). :slight_smile:

So now what I’d love to do is find a way to sequentally crossfade between poly channels. So like, start with the first channel at full amplitude and all others at zero, then crossfade from the first to the second, then when the first reaches zero and second reaches full, crossfade from the second to the third, then third to fourth etc etc.

Ideally this sequential crossfade would map to a single voltage in the end. So you could turn one dial to smoothly transition up the overtone series.

So, any ideas on good ways to achieve this?

(P.S. a very reasonable suggestion is to simply use a wavetable VCO and load a harmonic-series WT. I do that sometimes, but I’d love to be able to do this arbitrarily with any VCO)

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Maybe something like that:

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This maybe…
vcvrack-packone/ at v1 · stoermelder/vcvrack-packone (


Yep - That works simply and beautifully. Every time I see that module in use, I struggle a bit to remember what it does. The concepts don’t seem hard once you get it, but it is not easy for me to follow just by reading the manual. That is not meant as a criticism - I don’t have any ideas on how to improve the documentation.

So I find it difficult to wrap my head around it, but well worth the effort.

Morphing Harmonics.vcv (1.8 KB)


Hey thanks! I did find that Harmonic/Subharmonic generator when looking around for this. Seems useful. :slight_smile:

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That’s exactly what I’m looking for right there! :slight_smile: Question, I’m not finding your brand in the VCV library, why is that? I’m trying to avoid option paralysis at this stage so would rather not install anything I don’t need, and I don’t know if I could work out how to build just the Rotor module. :wink:

it’s a long story and best advice is to search the forum for answers before asking a question asked multiple times, but he is going to release to the library when he’s ready.

Oh of course. Gotcha! Looking forward to it then. :slight_smile:

Your harmonic series crossfade idea inspired me to create a four voice drone piece that I am very happy with:


just a little plug. my ancient VCV “Chebyshev” has 10 CV inputs to control the level of the first 10 harmonics. I doesn’t take hardly any CPU, and you don’t need deal with polyphony to do it.


hello, unfortunately i got an error messaage: Could not load patch: Unarchiver could not write file to dir: Can’t create ‘/home/held/.Rack2/autosave/modules/3387174519679520/wavetable.wav’

What does it mean? Where could i dl the wavetable.wav?

Cheers Karl

Can you open the patch?

no, the error comes up during loading. afterwards Rack is empty.

That Squinky always tooting his own horn! :grin:

In the patch below I replaced the wavetable VCO with the classic VCO.

crossfaded-harmonics_no_wavetable_vco.vcv (2.3 KB)

wonderfull, it works! thank you. i will try to understand and play with that patch :slight_smile:

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It’s a dirty job, but someone has to do it. I also have a feeling it would be much easer to get this effect if you started with a VCO that has independent CV control of each harmonic, but I guess not.

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