Maybe this can already be done, and I just don’t know how?
My Montage 7 has this really nifty feature where I can give it a line in from my drummer or bass player and it syncs the live set’s (like a rack) tempo with the incoming audio. My guess is it uses something like a “beat detective” and changes the bpm.
The coolest thing is that it can FOLLOW the incoming audio, so if my drummer gets frisky and jumps 10bpm by the end of the tune, my arps and LFOs stay in sync with him.
There’s a YouTube video that shows a group doing this.
If Yamaha can squeeze this into the Montage’s processor, there has to be a way to do this on an actual computer.