Techniques Used to Create Polyphonic Tones

Doubling is used to create a honky-tonk type sound. It is created by composing one track, then creating a second track identical to the first but slightly detuned.

Another trick is to create a MIDI echo. The idea is to run two tracks simultaneously, but play one a few milliseconds behind the first and therefore create a MIDI delay.

Faking the Filter, Velocity and/or MIDI volumes (controller 7) can be used to achieve a kind of filter effect, by duplicating a track, picking sounds with very different timbres, and cross fading between the two tracks.

Big Bend, MIDI Pitch Bend Sensitivity can be altered and set to large intervals (e.g., two octaves) to simulate portamento or ravey synth effects.
The SP-MIDI format can be used to stylize an entire phone with similar sounding tones from ring tones to alerts and alarms. Ring tones are fun for users and are serious business.