Musical Instrument Digital Interface

MIDI (Musical Instrument Digital Interface) became the USB of music—a universal language that let synthesizers, computers, and instruments from different manufacturers communicate. Like Tim Berners-Lee with the web, Dave Smith and his rivals-turned-collaborators gave MIDI to the world for free, and an entire industry flourished on their generosity.

The adjacent possible emerged from incompatibility. By 1981, synthesizers from Roland, Oberheim, Sequential, Yamaha, and others each spoke proprietary languages. A musician couldn't connect a Roland to a Sequential without expensive custom interfaces. Dave Smith, founder of Sequential Circuits and creator of the Prophet-5 (the first microprocessor-based synthesizer), set out to create a universal protocol.

Smith and Chet Wood presented their 'Universal Synthesizer Interface' proposal to the Audio Engineering Society in 1981. Meetings with Tom Oberheim and Roland founder Ikutaro Kakehashi followed. The Japanese suggested 'Universal Music Interface' (UMI); Smith countered with 'Musical Instrument Digital Interface.' MIDI it was.

The specification took shape through transatlantic collaboration. Sequential and Roland engineers refined the protocol, balancing simplicity with capability. MIDI transmitted note data—which key was pressed, how hard, when released—not audio itself. This meant tiny data rates: the entire protocol ran at 31.25 kilobits per second, manageable by early 1980s microprocessors.

The technology debuted at the Winter NAMM Show in January 1983, when a Sequential Circuits Prophet-600 successfully connected to a Roland Jupiter-6. The Prophet-600, shipped in December 1982, was the first-ever MIDI product. Within years, MIDI became universal.

The cascade transformed music production. Musicians could layer sounds from multiple synthesizers. Computers could record and play back performances. Software could generate and manipulate musical data. Home studios became possible because MIDI democratized tools that once required expensive recording facilities.

Smith and Kakehashi received the Technical Grammy Award in 2013 'for their contributions to the development of MIDI.' When Smith died in 2022, the Guardian noted that MIDI remained 'as important to music as USB is to computing.' The 1983 specification, with extensions but no breaking changes, still works in 2026—a testament to the wisdom of getting the fundamentals right and giving them away.