Bog Audio FM-Op Ratio CV Control

Spent the day lost in FM land with Bog Audio’s FM-Op. What an incredible module. One thing that I’m confused by is that the ratio is not controllable via CV. You can get some incredible effects (manually) moving either the modulator, or the carrier around through related ratios, and it would be wonderful to be able to automate this. It doesn’t appear that there are any other modules that offer this, so I have two questions:

  • why is this parameter not cv-controllable?
  • is there a work around?

I also use Reason, and it uses a ‘Combinator’ which is a device that wraps other devices and allows its own CV inputs to be mapped to any manual controls the devices have. This allows automation of almost any parameter, including those without CV inputs. I’m pretty sure there is nothing equivalent in VCV.

Try this:


… or ask Matt Demanett directly and make a feature request on Bogaudio’s repository on GitHub :slight_smile:


The ratio control just changes the base pitch with a more convenient UI. So just modulate the V/Oct input. btw - gratutious plug - I made an FM operator that is similar, but adds a waveshaper and other goodies. If you are bored you might check it out.


Thanks. FM Kitchen Sink looks great. I’ll definitely check it out.

I’ve tried modulating the V/Oct by different values, but I’ve found the results to be inconsistent. If I put two set of operators up against each other, one set using the ratio controls and one set using multiplication of the V/Oct, it seems to be impossible to truly match them up (using Analyser) so there is definitely something else going on in there. It’s also quite confusing mentally mapping fixed voltages to ratios.

Thanks. That does the trick!

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