SP Studio Systems SP-12 manual Appendix D Understanding MIDI/SMPTE, What does the Midi cable do?

APPENDIX

APPENDIX D: UNDERSTANDING MIDI/SMPTE

MIDI is causing a certain amount of confusion among musicians. Fear not -- it’s not all that difficult to understand, and the SP-12 makes it particularly easy to deal with MIDI.

For those of you who aren’t that familiar with MIDI, we’ll first answer some common questions. -

What does the MIDI cable do?

An instrument already has an AC cord that carries electrical current, and an audio cord that carries audio signals to an amplifier. Now you have a third connection: the MIDI cable. This carries neither audio nor power, but transmits information about the status of the instrument to, and receives “status reports” from, other MIDI instruments. This information is coded in a computer language. . a somewhat primitive language with few words and several dialects, but a language nonetheless.

What does MIDI stand for?

MIDI stands for Musical Instrument Digital Interface. You already know what “musical instrument” means, so that takes care of the first half of this phrase. Digital means that the instrument’s information is conveyed in digital, or computer, language. Interface is the term for the actual link between instruments, where data passes from one instrument to another. So MIDI is a link between musical instruments that speaks data in computer language.

How can information control a synthesizer or drum machine?

First we need to know a bit about computers, since MIDI instruments have microcomputer souls...in fact, MIDI could not exist without microcomputers.

Computers are decision makers, and they base those decisions on the data they receive. However, to be useable by a computer any data has to first be translated into a number-based language that the computer can understand. Actually, when you press a keyboard key with a computer-based instrument, you are not directly [[controlling the sound source. Instead, each time you close a keyboard switch you’re sending a number to the computer, and this number tells the computer what note you want it to play for you.

The computer’s “window on the world,” where it receives and transmits numerical data, is called its data - The computer looks to see whether any information is on the data bus, and if so, acts on this data. For example, if it sees a digital “word” that says “play F#” on the data bus, it will do as the data commands and control a sound source so that it plays an F#. However, note that the computer doesn’t care whether this word is placed on the data bus due to closing a keyboard switch or striking a drum head -- once MIDI translates a note into computer language, the note becomes compatible with any device that speaks the same language. MIDI provides access to the computer’s data bus and selects which device will be “on the bus” at any

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