MIDI

Musical Instrument Digital Interface, commonly known as MIDI, is a technical standard for communication. It describes a protocol, a digital interface, and the electrical connectors used to link electronic musical instruments. This system also connects computers and other related audio devices.

MIDI is essential because it allows diverse devices to play, edit, and record music together. It does not transmit actual audio signals like a microphone does. Instead, it transmits digital data that acts as a set of musical instructions. This distinction makes MIDI files very small and easy to manipulate compared to traditional audio recordings.

To understand how MIDI works, imagine a conductor giving orders to an orchestra. When a musician interacts with a MIDI controller, such as a keyboard, the device converts that action into a MIDI event. A MIDI event is a digital message containing specific instructions. These instructions include the pitch of the note, the timing of when it is played, and the velocity, which describes how hard the key was struck.

A single MIDI cable can carry data across up to sixteen different channels. Each channel can be routed to a separate device. This means one single controller can trigger a drum machine, a synthesizer, and a sound module simultaneously.

This capability allows a musician to create a massive, layered sound from a very small amount of hardware.

MIDI technology offers several distinct functional applications. The first is instrument control, where one device triggers another. For example, a sequencer can send instructions to a sound module to play specific beats. Musicians can also use MIDI for remote control of instrument parameters. These parameters include volume, effects, and timbre.

Using a continuous controller number, or CCN, a musician can use knobs or sliders to change settings like reverb time or filter frequency. The second major application is composition. Because MIDI records instructions rather than sound, composers can use Digital Audio Workstations (DAWs) to edit music easily. They can change the tempo, the key, or even the specific instruments used after the performance is recorded.

Before MIDI was standardized, the electronic music industry faced a major problem with interoperability. In the early 1980s, different manufacturers used their own proprietary standards to synchronize instruments. These included systems like CV/gate, DIN sync, and Digital Control Bus (DCB). Because these systems were not compatible, instruments from different companies could not communicate. This limitation hindered the growth of the electronic music industry.

To solve this, Ikutaro Kakehashi, the president of Roland, proposed creating a universal standard in June 1981. He reached out to Tom Oberheim and later spoke with Dave Smith, the president of Sequential Circuits.

Dave Smith and engineer Chet Wood worked to devise a universal interface based on Roland's DCB. They proposed this standard in a paper titled "Universal Synthesizer Interface" in October 1981. While Kakehashi initially suggested the name Universal Musical Interface (UMI), Smith proposed the name Musical Instrument Digital Interface instead. The MIDI specification was officially published in August 1983. The first instruments to feature this technology were the Roland Jupiter-6 and the Prophet 600.

In that same year, the Roland TR-909 became the first MIDI drum machine, and the Roland MSQ-700 became the first MIDI sequencer.

The significance of MIDI to the music industry cannot be overstated. It allowed for a rapid expansion in the production of electronic instruments and music software. By allowing one device to control many others, it reduced the amount of heavy hardware musicians needed to carry. MIDI also helped establish the era of home recording. Artists could compose and arrange music in a home environment before going to an expensive studio. This reduced costs and changed how music was produced. In 2005, Dave Smith's original MIDI specification was inducted into the TECnology Hall of Fame for its enduring impact on audio technology.

Today, MIDI continues to evolve and connect with modern computing. The standard has been adapted to work with USB and FireWire connections. The MIDI Manufacturers Association (MMA) and the MIDI Committee oversee the development of new versions. A new standard, MIDI 2.0, was introduced at the 2020 Winter NAMM Show.

Even with these updates, the core concept remains the same. MIDI acts as a universal language that enables cooperation between different technologies, much like USB serves the world of computing.