OK… So, I thought I’d find a VST somewhere to do this, but the closest I’ve found is a Ableton Live proprietary plugin, which I can’t use.
What I’m trying to do is filter out all notes but the the lowest active note. Think of it like a moving key-range that is one note wide and is always the lowest held note. Its a bit hard to describe, but I’ll try.
The idea is to be able to play a chord, and filter out all but the lowest note, and send that note to a different plugin, like a sub-base or something. When note-off is sent to the lowest note (and there is no sustain), it waits for the next note-on, and if that note-on is lower than any other held notes, this note-on is passed through and becomes the lowest note. If a new note-on occurs that is lower than the current lowest note, a note-off is sent for the current lowest note and the new note gets a note-on and becomes the new lowest note.
Conceptually, think of sending the lowest played note to a sub-base plugin, monophonically.
I haven’t figured out a way to do this with C3, nor have I found a VST to do this.