MIDI carries digital performance data — notes, tempo, position — over one cable across up to 16 channels

MIDI is a widely adopted digital protocol that lets instruments exchange performance information: what note to play and when, the song’s tempo (BPM), and the current position in the song. Physically it runs over 5-pin DIN, USB, or 3.5mm TRS cables. A single MIDI cable carries up to 16 independent channels (more over USB), so one cable can address many separate sounds, or — via a MIDI Thru box — daisy-chain several instruments. MIDI carries no audio; it only carries control data, which is why a MIDI-connected rig still needs separate audio cabling to a mixer. Understanding that MIDI is control-only, multi-channel, and cable-agnostic is prerequisite to wiring a multi-machine setup.

Examples

A sequencer sends channel 1 to a bass synth and channel 10 to a drum machine over a single DIN cable; a MIDI Thru box fans that cable out to three more instruments.

Assessment

How many channels can one MIDI cable carry, and what kinds of data does MIDI transmit? Why does a MIDI-linked rig still need separate audio cabling?