This is impressive for a gamejam. Its like a grid puzzle DAW haha
Love the ideia, wish there were some objective to add some depth to the game. It is more like a toy for now. But it is a well done toy.
I feel like sometimes the sound would not go through a straight line, and than I had to redraw the line and then it worked. Not sure why.
And if you keep working on the project, maybe some usability features would help, like keys to change between tools, easier way to change the note of the modulator or instrument of the percussion would be nice.
My game is also music related, more a rhythm game, though. You might like it, give it a try! :)