Auto frequency decreasing


I would like to build an automatic decreasing of a VCO frequency, and this from a starting note and gate or trigger.

Here is the idea: 1/ I get a note and a gate from a MIDI keyboard, Or: A note and a gate from Entrian. 2/ So I have the « starting note ». I need now to decrease it one octave bellow, and this automatically. This time, I’m not looking at a starting and final note from Entrian using a Slew limiter :grin:

I guess of course that I have to decrease the VC used to pitch the VCO. I tried many different assembly, using ADSR to pilot the pitch, or adding the Vc note with the one of an octave bellow and a slew limiter, etc. But…

I can’t do it. Could help!? Alain, France

Thank you! But I would like a portamento between the start ans the target note. I tested these modules from Baugodio, and all I have is a note on the outside, my target one, and that’s it.

How to say to my patch: « give me a portamento from the started note I give to you, to a target one wich is one octave (for instance) below? »


VCV have a new module called Fade. You can patch the starting CV(note) into one input and the ending CV(note) into the other. You can then route an LFO or whatever to the mix amount.

That’s one way. Another is to use CV mix (another new module from VCV) route your starting note to one input and an LFO (or adsr) to another input. Adjust the second attenuator to 10% to get one octave. (Assuming your LFO runs from 0 to 10 volts).

There are alot more ways.

? Offset for the inital Oct, Scale at -.2 for down portamento of 1 Oct, Sustain 50% and Release sets the glide speed

(although there’s a weird spike coming from DADSR’s attack, maybe a different module is better suited)

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“Insert slew limiter on pitch CV” :slightly_smiling_face:

CV-slopes.vcvs (5.4 KB)
(File → Import Selection)


You can bypass the 8vert by making the 2nd attenuverter on CV mix -10%.


CV-slopes.vcvs (4.4 KB)
(File → Import Selection)

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Thank you for all your responses! Working on them ;o)

Your idea works great for me. Thank you so much! I still have 2 things I don’t understand:

  • Why do we have to use the INV output ? DADSR gives me a decrease signal, so I would have taken that signal and substract it to the note pitch…
  • The SUMS module is a mystery when I study it with scopes…

Any way, thank you! Alain, France

Thanks to your idea, that’s what I have… We have lot of these types of sounds in JM Jarre music :o)

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Oh, INV just so happend. It’s either way, just invert the OFFSET accordingly (+0.2) And VCV’s own ADSR is better here. The Bogaudio one seems to have a short Attack phase, even if set to 0.

Interesting! Thank you ;o) This different approach gives me different ideas…

Alain, F

But I can use à Slew limiter, because I have only one note. Do I misunderstood ?