TidalCycles looks like the kind of thing I should learn* how to use. It provides plenty of tools for sound mangling. It runs on top of Super Collider. You write the code giving the instructions to make the sound which is then passed back in to the system (when the line flashes green in the video below) to be processed and your sound is returned. The sound is played in a fixed loop – so the more notes the faster they will play so they fit into the loop.
*By learn I mean throw random numbers and brackets at it and see what comes out. This is an initial exploration – which I am probably doing all wrong :-/