MIDI

MIDI describes events, not sound: "key 60 pressed with velocity 100", "key 60 released", "turn knob 7 to value 90". That is why a MIDI file is a few kilobytes where the equivalent recording is tens of megabytes, and why the same file sounds completely different depending on which synth interprets it. The standard was drawn up jointly by Roland, Sequential Circuits, Yamaha and Korg and presented in 1983 — competitors agreeing on one format instead of each building their own.

Its longevity is remarkable. The original specification is largely unchanged after forty years, the DIN connector has given way to USB but the protocol underneath has not, and every modern digital audio workstation still rests on it. MIDI 2.0 arrived in 2020 with higher-resolution velocity and two-way communication, but backwards compatibility was a stated requirement.