MIDI — the cable that organized music
MIDI carries no audio. It's a stream of tiny event messages — this key went
down, this hard, on this channel — which is why a 1983 protocol at telephone-modem speed
still runs every studio: events are small, and meaning ages better than sound. Two rival
companies designed it, gave it away license-free, and four decades later it remains the longest-lived
digital standard in music. This page is the history and the bytes.
Anatomy: watch the bytes as you play
on the wire — press a key
Every message starts with a status byte (first bit 1): the high
four bits say what kind, the low four say which of 16 channels. The
data bytes that follow (first bit 0) are therefore only 7 bits —
which is why almost everything in MIDI runs 0–127, and why pitch bend glues two data bytes
into one 14-bit value to stay smooth.
The seven channel voice messages
| status | message | data bytes | what it means |
|---|
System messages
| status | message | what it means |
|---|
Controllers worth knowing by number
Wire facts: classic MIDI runs at
31,250 bits per second over a
5-pin DIN current loop, opto-isolated so grounds never hum. A three-byte message takes about a
millisecond — so a big chord
must arrive as an arpeggio too fast to hear (usually).
Running status lets a sender skip repeated status bytes to save a third of the
bandwidth. Watch all of this live from your own controller in the
MIDI Monitor.
1981 → today
MIDI 1.0 ↔ MIDI 2.0
| MIDI 1.0 (1983) | MIDI 2.0 (2020) |
|---|
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