It sends the notes you play to another device — a computer, a sound module or another instrument — as data rather than as audio. That is what lets a keyboard play software instruments or trigger a second machine.
Data, not audio
MIDI is a description of a performance. That is why a MIDI take can be corrected, transposed and given a different instrument after the fact, and an audio take cannot.
What it enables at home
Software pianos and synthesisers played from real keys, notation programs that follow what you play, and learning software that knows whether you hit the right note.
What you still need
An audio path — headphones on the instrument, or an interface — to hear anything. MIDI alone is silent.
The questions players ask
Is USB the same thing?
On most current instruments, USB-MIDI carries the same data over a USB cable. Five-pin MIDI sockets remain on hardware that talks to other hardware.
Does MIDI carry sound?
No. It carries which note, how hard, and when. The sound is produced at the other end, which is why a MIDI recording can be re-voiced afterwards.
Last reviewed 2026-08-19