MIDI by its self has no sound
it will require an instrument to be added
midi sends a note on and off
it can be plugged into a synth or sampler (module) with a 5pin midi cable
some synths will have a midi though port that will allow you to chain them together
if using a midi interface then in ablation you will need to use instrument external instrument
the midi device can then be adjusted on the fly while the track is happing