MIDI

MIDI, short for Musical Instrument Digital Interface, is a technical standard that describes a protocol, digital interface, and connectors enabling a wide range of electronic musical instruments, computers, and related devices to communicate.

Developed in the early 1980s through collaboration between Roland and Sequential Circuits, MIDI 1.0 was released in 1982–1983. It uses a serial data protocol at 31,250 bits per second and originally employed a five-pin DIN connector to carry messages across up to 16 channels per cable. The standard was designed to carry control information rather than audio signals, allowing devices to trigger sounds, synchronize timing, and exchange performance data.

MIDI messages include notes, velocity, gate information, and a family of control messages such as Note On/Off, Polyphonic Aftertouch, Channel Pressure, Control Change, Program Change, and Pitch Bend, along with System messages like System Exclusive. Messages are structured as status and data bytes, and the original format limited data to 7-bit values, though extensions and newer specifications have expanded capabilities.

In 2020, MIDI 2.0 was introduced, preserving backward compatibility with MIDI 1.0 while adding bidirectional communication, higher-resolution data, per-note controls, and MIDI-CI (Capability Inquiry) to negotiate device features and capabilities. This evolution aims to improve expressiveness and interoperability without discarding the established MIDI 1.0 ecosystem.

Transport options have expanded beyond traditional DIN cables to USB, USB-MIDI, Bluetooth, Ethernet, and other networks, enabling diverse configurations in studios and live environments. General MIDI (GM) also standardizes instrument mappings to ensure consistent playback across devices. MIDI remains a foundational technology for sequencing, production, and performance. It encodes performance data rather than audio, which is produced by synthesizers or software instruments.