Home Recording Basics: MIDI - dummies

By Jeff Strong

MIDI is a protocol that musical instruments use to communicate with one another. They do this through a cabled connection and a language that allows each one to understand the other, regardless of the manufacturer or instrument. All that’s required is an instrument equipped with MIDI ports (jacks).

MIDI data is different from an audio recording because it contains no sound as such; rather, it’s limited to performance information. This includes information about various performance characteristics, including the following:

  • *Note-on and note-off: What note is played and when

  • Velocity: How hard someone presses a key

  • After-touch: Whether the key pressure changes after the initial press

  • Vibrato and pitch bend: Whether the pitch changes while a key is pressed

This information allows the MIDI musician to potentially create a performance that is as rich in texture as those of the world’s finest players.

Digital messages that are sent from one device to another across a cable (called the MIDI cable, of course) create MIDI data. The cable connects to MIDI ports on each device, and the messages are sent in the form of binary digits. Each instrument can understand and respond to these messages.