MIDI

thumb|Example of music created in MIDI format thumb|alt=Several rack-mounted synthesizers that share a single controller|Using MIDI, a single controller (often a musical keyboard, as pictured here) can play multiple electronic instruments, which increases the portability and flexibility of stage setups. This system fits into a single rack case, but before MIDI, it would have required four separate full-size keyboard instruments, plus outboard mixing and effects units.

Musical Instrument Digital Interface (; MIDI) is an American-Japanese technical standard that describes a communication protocol, digital interface, and electrical connectors that connect a wide variety of electronic musical instruments, computers, and related audio devices for playing, editing, and recording music. A single MIDI cable can carry up to sixteen channels of MIDI data, each of which can be routed to a separate device. Each interaction with a key, button, knob or slider is converted into a MIDI event, which specifies musical instructions, such as a note's pitch, timing and velocity. One common MIDI application is to play a MIDI keyboard or other controller and use it to trigger a digital sound module (which contains synthesized musical sounds) to generate sounds, which the audience hears produced by a keyboard amplifier. MIDI data can be transferred via MIDI or USB cable, or recorded to a sequencer or digital audio workstation for editing or playback.