"To render the sound on your tablet or phone, you would attach the MIDI file to a song.
To send the MIDI data to another device to render the sound there, you would attach the MIDI file to a MIDI preset."
I have each of these cases working individually. But what if I want to render the bass on my tablet (via soundfont) and send the midi drum notes to an external module? I tried attaching the same midi file to both the song and to a midi preset, but it seems to then only send to the soundfont bass.