MIDI

Musical Instrument Digital Interface (MIDI)

Basically, MIDI is a ‘protocol’ (a set of rules and specifications) that allows different electronic instruments to share information.

The most common use is to provide an electronic musical instrument with the information that it needs to play a complete song. Imagine a player piano; MIDI is the roll of music that you put into it.

A set of MIDI instructions includes note info, but also pitch, tempo, volume, and nearly any other kind of info that influences the playback — and it can be sent to multiple instruments at once, synchronizing all of them (hopefully). This is sometimes referred to as “sequencing”, and the software that allows the user to compose or assemble a MIDI file is called a “sequencer”.

MIDI has about a zillion other uses, however. Because electronic instruments are complex, idiosyncratic, and sometimes extraordinarily flexible, MIDI had to be designed to be robust and flexible and scalable and all of those other words that executives use when they’re trying to sound ‘techy’.

The drawback is that the final sound cannot be guaranteed; though MIDI specifications are well-established and largely adhered-to, you’ll inevitably hear a MIDI file that sounds different on different machines…this may cause subtle differences in timbres, or even in extreme cases a partial or complete failure to interpret the MIDI information (i.e., weird noises or complete silence).