great instructable ! i am using your code now to drive relays via transistors so that i can program beats using old radios as the sound source (turned on and off by eight relays) I have come across an issue though that i dont understand at all,
When i plug the midi input straight into the midi out of my korg ms2000 everything works fine and dandy, however if i control the arduino with my edirol ua25 sound cards midi out the arduino will not handle two simultaneous notes. If i dont send a note of for the first note, i have to wait approx 1 sec until i can press a new note that it will handle, this happens with my edirol PCR-500 midi keyboard too. What is going on ? :-?