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.

 

For more information, see:

Audio playback in SONAR

Tracks

Clips

Track-by-track playback

Connecting an instrument, home stereo, or microphone to your sound card

Choosing inputs

Audio recording

Audio hardware (sound cards) and drivers

Audio

MIDI