IV. APPENDIX

APPENDIX A: What is MIDI?

MIDI (Musical Instrument Digital Interface) was established in 1983 by the MIDI Manufacturers Association to allow musicians to connect synthesizers together. MIDI allowed musicians to experiment with music in a new capacity. They could play more than one instrument all from the comfort of one keyboard.

Today, MIDI enjoys ubiquitous use in the computer industry. MIDI enhances the audio output in games and other multimedia software. MIDI, however, is not a software program, nor is it a music recorder. MIDI is divided into three different components: MIDI protocol, standard MIDI file, and the MIDI connector/cables.

PROTOCOL

The MIDI protocol is the language in which the MIDI files are written. The language does not contain the actual note but rather has the instructions on which note to play and how long to play it. The MIDI protocol basically is the conductor of the synthesizer.

CONNECTOR

MIDI files are shared through MIDI cables which carry data needed by each device in order to play the right music. The proper way to connect MIDI devices to each other and transmit the MIDI protocol is through the standard 5-pin MIDI DIN connector (shown below). Every device has both IN and OUT connectors usually located at the back of the device (shown below). These cables allow the MIDI information to flow from device to device.
 



STANDARD MIDI FILES

Standard MIDI files are files that carry or hold the MIDI protocol information. Just like other types of files like a text document they can be shared and copied and modified. Unlike other music files such as .wav files, MIDI files take up much less memory. Another comparative benefit is that MIDI files are editable while other types of files are not.

How does MIDI Work?

MIDI data, taken from a MIDI file, is transferred between devices through MIDI cables. The cable is divided into sixteen channels. The MIDI protocol does two things here. First it assigns the data to a certain channel and then it tells the MIDI receiving device what channel the data is on. The receiving device then tunes into that particular channel and receives the instructions for that channel such as what note to play and for how long.

One analogy that illustrates how MIDI works is that of a player piano. The punched roll represents the notes that need to be played on the piano. The reader on the piano player converts the roll punches into commands or pressure that actually presses the key down. The MIDI files are like the punched rolls. The reader is like a MIDI player and the piano is the synthesizer.