MIDI FORMAT
-----------

# event, wait-time, channel, note number, volume
  ['note_on', 0, 1, 25, 96],
  ['note_off', 96, 1, 25, 0],
  ['note_on', 0, 1, 29, 96],
  ['note_off', 96, 1, 29, 0],
  ['note_on', 0, 1, 27, 96],
  ['note_off', 96, 1, 27, 0],
  ['note_on', 0, 1, 20, 96],
  ['note_off', 192, 1, 20, 0],

 * duration: expressed as a quarter note, half note, etc.
 * pitch: expressed as a note-letter and octave number, e.g., "A5"
 * volume: expressed either numerically or as one of the common
   abbreviations from sheet music, e.g., "mf" for "medium-loud"
 * and, for purposes of MIDI, a logical channel number between 0
   and 15