What You Need to Know About Digital Audio
What is Sound?
The sound we hear is made up of tiny changes in air pressure.
Our ears detect these minute changes and transmit them
to our brain, which interprets them as sound. When we
make an audio recording, these changes in air pressure are
represented by changes in voltage. When we play back our
recording, we use a speaker to turn the changes in voltage
back into changes in air pressure that we hear as sound.
Digital Audio
To convert that analog signal into digital audio, we start with
a clock that marks off equal amounts of time. For each tick
of our clock, we measure the voltage of the signal and save
it as a number. The picture shows a grid marked off in time
ticks - each vertical line is a tick; the snaky line is our analog
audio voltage; and the black dots represent each value in the
corresponding digital audio data.
To convert our digital audio
back into an analog signal,
we use a matching clock;
this time, for each tick of the
clock, we read one number
off our list and convert the
number value back into a
voltage. Finally, after we use
some filtering to smooth the
signal and “connect the dots”,
