What is MIDI?

Introduction

A key component of modern electronic music is MIDI.

The Musical Instrument Digital Interface protocol was introduced in 1983, as a collaborative effort between major electronic instrument manufacturers including Korg, Roland and Yamaha.

MIDI allows compatible devices – usually keyboards, synthesisers, drum machines, sound modules, and computers – to communicate with one another using a standard, efficient ‘language’.

The MIDI protocol does not transmit audio, but rather information about notes, timing, and other related musical information.

Initially, MIDI was transmitted and received via 5-pin DIN plugs and cabling. More recently, MIDI hardware has evolved and now is often implemented via USB. Wireless MIDI is also in use.

MIDI 1.0

Standard MIDI is a fairly simple system, though more advanced add-ons have evolved including MIDI Time Code, the Sample Dump Standard, and MIDI Show Control.

Version one comprised of 16 channels, each which could carry various information about notes being played, voice changes, control changes for various parameters, and longer information streams used for transmitting and receiving synth/keyboard parameter data. This could be used as a way to backup, restore, and even edit with computer software, voice, patch, performance and system data.

One of the first readily-available MIDI-equipped computers was the (now virtually defunct) Atari ST range of computers. STs became commonplace in both professional and home studios, but were gradually superseded by more powerful PCs and Apple Macs.

Though MIDI is most often seen on keyboard-based electronic instruments, sound modules, and electronic performance pads and controllers, it has also made its way onto other electro-acoustic instruments—with varying degrees of success—including guitars, cellos and drum kits.

Some older mobile phones used MIDI as a basis for their ringtones.

Because MIDI does not transmit sound, just data about the sound, a MIDI track may sound quite different played on different instruments.

General MIDI was introduced in the mid-’90s as an attempt to standardise commonly used sounds across different manufacturers.

MIDI is certainly not ‘old-hat’ though – there’s a thriving community and most music-related equipment, both amateur and professional, can utilise MIDI.

MIDI 2.0

MIDI 2.0, introduced in 2020, offers higher communications resolution, increased controller options, and proper two-way communication between devices.

Developed by Yamaha, Roli, Microsoft, Google and the MIDI Association.

It is backwards compatible with MIDI 1.0, but has enhancements such as upping the number of channels to 256, increased resolution for controllers to 32-bit rather than 7-bit (a huge upgrade) and enhanced expression features.

MIDI 2.0 is still not universally implemented, and with the vast array of older instruments and other equipment still in use, it probably never will be. However, it is an important development in ensuring electronic musical instruments, computer and other equipment can communicate, control and be controlled in a predictable and uniform manner.

MIDI MPE

MIDI Polyphonic Expression is an extension to MIDI which allows for per-note, multi-dimensional control, for providing expressive, acoustic-like performances on compatible electronic instruments.

It takes concepts such as modulation and polyphonic aftertouch and turbo charges them. It allows for manufacturers to create much more expressive instruments, and have those be able to communicate with DAWs and other devices.

MPE can be used with MIDI 1.0 and 2.0. It uses multiple MIDI channels to transmit data, which means MIDI 2.0 would offer more bandwidth for this. The whole part of the performance chain needs to be MPE-compatible, otherwise data may be lost — this includes the controller instrument, the DAW and any software instruments being used.

Some hardware which can use MPE includes Expressive E Osmose, ASM Hydrasynth, Waldorf Protein, Behringer UB-Xa, Arturia PolyBrute 12, and the Roli Piano.

Compatible DAWs include Ableton Live and Logic Pro.