MIDI Controller - Use in A Data Stream

Use in A Data Stream

See also: General MIDI: Controller events

Modifiers such as modulation wheels, pitch bend wheels, sustain pedals, pitch sliders, buttons, knobs, faders, switches, ribbon controllers, etc., alter an instrument's state of operation, and thus can be used to modify sounds or other parameters of music performance in real time via MIDI connections. The 128 virtual MIDI controllers and their electronic messages connect the actual buttons, knobs, wheels, sliders, etc. with their intended actions within the receiving device.

Some controllers, such as pitch bend, are special. Whereas the data range of most continuous controllers (such as volume, for example) consists of 128 steps ranging in value from 0 to 127, pitch bend data may be encoded with over 16,000 data steps. This produces the illusion of a continuously sliding pitch, as in a violin's portamento, rather than a series of zippered steps such as a guitarist sliding their finger up the frets of their guitar's neck. Thus, the pitch wheel on a MIDI keyboard may generate large amounts of data which can lead to a slowdown of data throughput.

The original MIDI spec included 128 virtual controller numbers for real time modifications to live instruments or their audio. MIDI Show Control (MSC) and MIDI Machine Control (MMC) are two separate extensions of the original MIDI spec, expanding MIDI protocol to accept far more than its original intentions.