Understanding LFOs and modulation a little better

Greetings. I’ve got a few questions coming from the world of Eurorack to the world of MIDI.*

  1. Is it a feature/principle of the Hapax that it completely “takes over” a cc when you assign it to a modulation parameter? For instance, if I assign cc#74 to an LFO for my Super 6 desktop, the filter fader on the Super 6 no longer does anything. Is that how it’s supposed to work? I realize “offset” then sets the base level from which the LFO deviates. I just want to make sure I get it, as it’s different from how I’m used to doing things. I’m used to adding in CVs where the front panel control still do something.

  2. I am trying to create complex modulation. For instance, a pair of square wave LFOs where the second modulates the first. Let’s call them LFO 1 and LFO 2. If I assign LFO 1 to filter cutoff, and then LFO 2 to the rate of LFO 1, the “rate” control for LFO 1 no longer does anything. So is the base rate now controlled by “offset” of LFO2, which is modulated by “rate” of LFO2?

  3. Can track effect LFOs be assigned to multiple destinations? Similarly, can I set up cross-modulation between two LFOs – for instance, where a tiny bit of the output of LFO 1 modulates the rate of LFO2 in the above scenario?

  4. I haven’t messed with the mod matrix yet – I kind of assumed that was for things like sending a CV input to a CC output, or converting a CC input to a different CC number for an output, but perhaps there’s a way to use it to achieve what I want?

Thanks for any insight you can offer.

  • Technically I started on MIDI but most of the way I think about modulation now is from my modular experience.
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Hi !

  1. This would seem to be the specfific implementation of the Super 6. It is quite common to go for the “override model” in the MIDI world.

  2. So is the base rate now controlled by “offset” of LFO2


  3. Not natively, no. However you could perhaps use a clever MIDI loop. Say you send the MIDI to OUT A to the super 6, and patch the super 6 THRU back into IN A of Hapax. Then you set up the track to listen to IN A. Then you setup the modmatrix so that CC74 (the output of LFO1) modulates the rate of LFO2 a little bit. Bear in you’ll need to be careful to filter out the notes in the MIDI IN settings, or you’ll get MIDI note feedback and possibly some other MIDI message feedback.
    TL;DR: it’s probably possible, but not easy.

  4. ^

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It’s pretty common for MIDI synths to map onboard controls to absolute CC values. Eg, all the way down is 0, halfway up is 63, fully up is 127. And they usually just use whatever the last value was, whether it was set via the control or via an incoming MIDI message. For example:

  1. Set the slider on the synth to halfway → parameter is set to 63
  2. Receive corresponding MIDI CC value of 20 → parameter is set to 20
  3. Set the slider on the synth to just above halfway → parameter is set to 64
  4. (etc)

With MIDI, each CC value is a digital message that is sent at the moment the parameter changes, and usually the synth makes no distinction between a CC value sent via internal vs external control. It would actually be fairly complex, and require extra work, for a synth to use an internal control as an offset. And there would be tradeoffs, like that control would no longer be able to send MIDI CC messages that a sequencer could capture.

With modular, it’s super common for incoming CV to be added to the internal CV generated by a knob (resulting in the knob working as an offset), because modular devices don’t need to be particularly smart about voltages, and can just add them together. But you can’t turn a knob on a modular voice and have a sequencer capture and replay that, like you can with MIDI devices. There are trade-offs either way!

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some synths you can do this using their modulation matrix input (or similar) - as modulation matrix are usually/often an offset to the thing its controlling.
but indeed its very synth dependent.

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Thanks everyone. This helps a lot. It also suggests that for some kind of complex modulation, I’ll get there a lot faster with a couple Eurorack modules mixed together and going into the CV in slot, and then just routing it where I need it.