Two apps i know allow you to do this:braj wrote:the built-in synth isn't controllable via the midi apps, I don't believe.
Triad MIDI Slave Manager:
http://www.df.lth.se/~triad/triad/ftp/MIDI/midislav.txt
M64:
http://gallium.prg.dtu.dk/anyware/
Both of which require one of three different MIDI interfaces,
DATEL / Siel+JMS / Passport or Sequential MIDI-interface
Im lucky to have found a passport
http://plogue.com/davidv/c64/passport.jpg
and a Sequential, but this one is a standalone thing, and has its own built in sequencer:
http://plogue.com/davidv/c64/sequential.jpg