Any free open-source sequencer/synths environments?

I’m looking for something like reason, even if it’s just a cakewalk-style sequencer with VST plugin support. This might also be something interesting to incorporate into blender directly… wish I could program… blender would be an undeniable force.

seems like audio oscillators tied into a sequencer wouldn’t be nearly as hard to program as all the shit blender’s currently capable of.