MIDI Saving sound files as MIDI files is often a good choice when you're looking for quality sound with the smallest file size possible. To make a MIDI file, it helps if you know a little about music or can play an instrument. You have to have MIDI software that gives the computer instructions about things like what notes to play, how long to hold them and what sound should be used. You also need some instrument source. Most MIDI software lets you create several parts or tracks.
Tracks refer to the different parts of the music.
A bass part would be a track, and a saxophone part would be another track. When using MIDI software, you choose the instrument sound you like or simply play the notes you'd like to use for your first track. If you're using a sound source such as the QuickTime instrument set or Beatnik sounds from your sequencing software, you can choose notes using your computer keypad and assign each note a length. If you have a MIDI instrument, you can just play the sound and record it to the track. You can download many MIDI arrangements of all kinds of songs.