Audio + Midi Interface

In June 1981, Roland founder Ikutaro Kakehashi proposed the idea of standardization to Oberheim Electronics founder Tom Oberheim, who then talked it over with Sequential Circuits president Dave Smith. In October 1981, Kakehashi, Oberheim and Smith discussed the idea with representatives from Yamaha, Korg and Kawai.

Sequential Circuits engineers and synthesizer designers Dave Smith and Chet Wood devised a universal synthesizer interface, which would allow direct communication between equipment from different manufacturers. Smith proposed this standard at the Audio Engineering Society show in November 1981.:4 Over the next two years, the standard was discussed and modified by representatives of companies such as Roland, Yamaha, Korg, Kawai, Oberheim, and Sequential Circuits,:22 and was renamed Musical Instrument Digital Interface.:4 MIDI's development was announced to the public by Robert Moog, in the October 1982 edition of Keyboard magazine.:276

By the time of the January 1983 Winter NAMM Show, Smith was able to demonstrate a MIDI connection between his Prophet 600 analog synthesizer and a Roland JP-6. The MIDI Specification was published in August 1983. The MIDI standard was unveiled by Ikutaro Kakehashi and Dave Smith, who both later received Technical Grammy Awards in 2013 for their key roles in the development of MIDI

MIDI was invented so that musical instruments could communicate with each other and so that one instrument can control another. Analog synthesizers that have no digital component and were built prior to MIDI's development can be retrofit with kits that convert MIDI messages into analog control voltages.:277 When a note is played on a MIDI instrument, it generates a digital signal that can be used to trigger a note on another instrument.:20 The capability for remote control allows full-sized instruments to be replaced with smaller sound modules, and allows musicians to combine instruments to achieve a fuller sound, or to create combinations such as acoustic piano and strings. MIDI also enables other instrument parameters to be controlled remotely. Synthesizers and samplers contain various tools for shaping a sound. Filters adjust timbre, and envelopes automate the way a sound evolves over time. The frequency of a filter and the envelope attack, or the time it takes for a sound to reach its maximum level, are examples of synthesizer parameters, and can be controlled remotely through MIDI. Effects devices have different parameters, such as delay feedback or reverb time. When a MIDI continuous controller number is assigned to one of these parameters, the device will respond to any messages it receives that are identified by that number. Controls such as knobs, switches, and pedals can be used to send these messages. A set of adjusted parameters can be saved to a device's internal memory as a "patch", and these patches can be remotely selected by MIDI program changes. The MIDI standard allows selection of 128 different programs, but devices can provide more by arranging their patches into banks of 128 programs each, and combining a program change message with a bank select message.