In 1984, MIDI (Musical Instrument Digital Interface) was introduced. MIDI enables the instruments made by different companies to be linked electronically. This allows a single performer to play more than one instrument simultaneously using one keyboard or another controller (e.g. software), regardless of the brand and manufacturer of the equipment. The control signals from a single keyboard are sent via the MIDI interface to other synthesizers that are linked to it, thus allowing music to be orchestrated using a variety of MIDI compatible instruments.
MIDI was a natural consequence of a microcomputer and an inexpensive connection of an electronic musical instrument with a computer.
What does MIDI do? It reports the values of the notes played on the keyboard, including pitch, amplitude, and duration. This should not be confused with recording sounds played on the keyboard; MIDI only "records" a sequence of note values. The timbre or quality of the sound comes from the synthesizer that receives the MIDI sequence. The sequence of the MIDI note values is independent of the timbre or voice of the instrument that is playing the notes. The same sequence of the note values can be played on different instruments using different voices.
The MIDI control signal can convey several parameters related to musical notes that are independent of the instrument on which they are played. These parameters include the pitch value, the amplitude of the note (the strength of the note being played), the effect of using the pitch-bend wheel, modulation wheel, and volume pedal, and the force of pressing a key while the note is held.
The MIDI interface was designed with two basic uses in mind:
• MIDI can link standalone electronic musical instruments and allow one instrument to control the sounds produced by several others. This can be done without a separate computer. The instruments may or may not have a keyboard, although a typical multi-instrumental configuration has at least one keyboard which controls all the operation.
• MIDI can link standalone electronic musical instruments to a computer. In this configuration, the computer is used to trigger the sounds and waveforms on the connected instruments. This way, you can handle multiple MIDI channels simultaneously.