Reference Guide

57
Computers, sound and music
Introduction
Computers, sound and music
This section provides some background on the different ways that computers store and play sound
and music. Computers work with sound and music in two different forms: MIDI and digital audio.Next
topic: “MIDI” on page 57.
MIDI
MIDI (short for Musical Instrument Digital Interface) is the way computers communicate with most
sound cards, keyboards, and other electronic instruments. MIDI refers to both the type of cables and
plugs used to connect the computers and instruments, and to the language those computers and
instruments use to talk to each other. The MIDI standard is accepted and used worldwide. Almost
any electronic instrument you buy today will have MIDI connectors and can be used with other MIDI
instruments and with your computer’s MIDI interface. To record MIDI in SONAR, you have to have a
MIDI cable connecting the MIDI OUT port on your MIDI instrument to a MIDI IN port on either your
sound card or your MIDI interface. You must also make sure that you have installed the software
MIDI driver that came with your sound card or MIDI interface.
The MIDI language conveys information and instructions, both from the computer to the instrument
and from the instrument to the computer. For example, if your computer wants your keyboard to play
a note, it sends a MIDI “Note On” message and tells the keyboard which note to play. When your
computer wants the keyboard to stop playing that note, it sends another message that stops the note
from playing.
The MIDI language has many other instructions, such as messages to change the sound that is
used to play the notes (the bank and patch), messages that enable working with the sustain pedal
and the pitch-bend wheel, and others. By sending the right messages at the right times, your
computer can control your electronic instrument and make it play music.
MIDI information can be sent on 16 different channels. You can set up your MIDI equipment to listen
for messages on all channels or on only a few.
MIDI files contain all the MIDI messages and timing information that are needed to play a song. MIDI
files can be read and played by many different programs, including SONAR, and can even be played
by programs on other types of computers. MIDI files have the extension .mid.
There are several important advantages of the MIDI format:
• Large amounts of music can be stored in a very compact form
• Different parts of a piece can easily be assigned to any instrument you can imagine
• The music contains information on notes, tempos, and key signatures that makes it possible to
display and edit the piece using standard musical notation
The primary disadvantage of MIDI is that the quality of the sound a listener hears will vary depending
on the MIDI equipment the listener is using. For example, MIDI usually sounds much better on an
expensive synthesizer than it does on an inexpensive sound card.
Next topic: “Digital audio” on page 58.