MIDI stands for Musical Instrument Digital Interface and is a specification created in the late 1980's to try and create a unified way of connecting devices to each other in a studio environment.
MIDI 1.0 began in the late 1980's to try and create a method of being able to interface pieces of hardware together in the aim of connecting them to a computer in order to capture the output of the device.
The concept was to create a universal language for audio equipment.
MIDI became very popular very quickly and many manufactures decided it was best for them to include the 5 Din MIDI connector onto all of their devices. This made MIDI universal. With the development of the computer swell it was now possible to do a lot of home audio recording and sequencing at home, with relatively cheap equipment. Most Electronic keyboards and synthesisers by the mid 1990's contained a MIDI interface in order for them to be connector to other outboard equipment as well as computers.
In the late 1980's software such as Sibelius and Finale made it possible for notating MIDI data for easy viewing and printing. Scoring on the computer saved a lot of time and effort. Sibelius was built on the concept of a word processor, allowing MIDI controller messages being transcribed just like binary letters appear on the screen. Later development saw DAW's building in MIDI capabilities to allow more slipstreamed integration of most Audio and Sequencing tools. MIDI is an essential part of the studio.
There are many different pieces of equipment that can be used with MIDI:
MIDI can send two types of messages:
System - System Messages are designed to be sent to change a setting on a piece of hardware. This travels most of the time through the THRU connector until it finds the piece of hardware it needs to communicate to.
Controller - A controller message can be anything from Note value to Note-Down and Note-Release. When analysing the data from MIDI most of the time we only see the controller messages.
MIDI use a simple 5 DIN connector in order to connect to all of the devices. The order that the devices are plugged in doesn't really matter. On the back of most devices there is an IN, OUT and THRU connector. The IN acts as an Input, OUT as an output and THRU as a way of daisy chaining devices together.
MIDI Files are very small in file size and can contain a lot of DATA, this enabled musicians to create pieces of music that can be played on most computer hardware that has a sound card. This has enabled the development of more MIDI files and replications of commercially available songs, which have been created at home on cheap equipment. In the early 2000's with the introduction of the internet it was popular for people to share MIDI files on their websites. This has since allowed more people to collaborate on them and share them further. Due to MIDI's compactness it was possible to use MIDI files as ringtones on early mobile phones, as most of the operating systems of these phones were JAVA based, and MIDI is a key component to JAVA's sound module. Later
MIDI can now be used to control most things not just audio equipment, for example MIDI can now be linked with OSC to allow connectivity to other devices such as home automation systems and other home gadgets. The introduction of the iPhone and iPad has allowed software such as TouchOSC to allow the device to be converted into a MIDI Controller.