Reference Guide

1224
Beginner’s Guide to Cakewalk Software
Audio
other messages that are meant for a different instrument on the chain. This setting is usually called
MIDI Receive, and might be abbreviated on an instrument’s control panel as MIDI RX.
Since most projects have several tracks in them, and each track is usually assigned to a different
sound, how do you control what sound you hear when you press a key on your MIDI controller?
In Cakewalk programs, one of your tracks is always a tan color, because it has the focus. Whatever
track you click grabs the focus, and the sound that’s selected for that track will sound when you play
your keyboard.
For more information, see:
Audio
Audio Hardware (Sound Cards) and Drivers
MIDI Channels, Interfaces, Inputs, and Outputs
MIDI Drivers
MIDI Files, Projects, Tracks, and Clips
Controlling Which Sounds You Hear
MIDI
Audio
The audio format works by converting any sound that’s recorded into a long series of numbers,
storing and usually editing the numbers, and then converting the numbers back into sound.
When you record sound using this format, the microphone you use causes the voltage in its cable to
change rapidly as the mic’s diaphragm vibrates. These rapid changes in voltage are measured and
recorded by an analog-to-digital converter, and these measurements make up what we call digital
audio. To convert digital audio back into sound, a digital-to-analog converter uses the stored
numbers to cause the voltage in a cable to change rapidly, and this voltage then moves the
diaphragm in a loudspeaker in a similar way to the way that the microphone’s diaphragm moved
originally (unless the numbers have been edited to produce a more desirable sound). These
converters, commonly referred to as A to D or A/D, and D to A or D/A, are part of your computer’s
sound card. Better sound cards usually keep their converters in a separate box that’s not in the
computer itself, because the computer’s fan and disk drives add noise to the sound card’s signal.
Digital audio works like cartoon animation. In a cartoon, a series of still photographs is displayed
rapidly in sequence to make it look as if the objects in the photographs are moving. When digital
audio is converted back into sound, the voltage is changed at regular intervals to simulate
continuous sound. To make high-quality sound, the original voltage during recording has to be
measured, or “sampled,” at rapid enough intervals to fool your ears into hearing continuous sound.
Audio CDs use a sampling rate of 44,100 per second. To store and edit so many numbers places a
big load on most PCs, much bigger than the processing of MIDI data causes.