Quote: "If you pause,resume, then loop a midi,the midi plays back in piano?! I think thats REALLY Cool, because now you can have upto 64"
This is what's happening:
Midi is basically a bunch of events; on/off switches, note numbers, timing, things like that. Each microsecond, the events are looked at to tell the midi controller or the midi device (the thing that plays back the midi - sound card, keyboard, etc) what to do.
Some events are sent every time a midi note plays: what's the timing, the note number, the velocity (how fast was the note activated - similar to how hard was the note played) - the channel to play on, and there are other events. An instrument change, is not necessarily sent with the other midi events. It's usually only sent at the beginning or whenever a channel needs to change to a different instrument sound.
When you stop or pause midi, depending on the playback software or hardware, it resets all of the events to defaults. For instruments, that default is instrument 0, which happens to be piano. So when you resume playback, the other events go on playing correctly because they are sent with each time code, but the instruemnt has been set to 0 and will only change when it comes upon another instrument change event.
So, it's not really giving you more tracks. You could accomplish much more varied combinations of instruments if you put instrument program change events in the midi file.
Enjoy your day.