Game Development Reference
In-Depth Information
Analog versus digital
Sound recording involves recording an original set of sound waves and reproducing
those waves in a variety of ways. The two basic recording methods are called analog
and digital. Both types of recordings require a sensor, such as a microphone or an
electric guitar pick-up. With analog recording, a physical record is created by moving
a phonograph stylus to imprint a pattern on a vinyl record or fluctuating a magnetic
field via a magnetic tape recording head.
Digital recording bypasses the physical element and creates a record directly on
a hard drive or other digital medium as a series of binary numbers representing
samples of the amplitude of the audio signal at regular intervals. An advantage of
digital over analog recording is the ability to make an exact replica of the file. Analog
duplication often results in a degraded quality replica.
Both the methods use analog playback by vibrating the head of a speaker or head-
phone to replicate the original sound waves.
Recording and playback
This section covers the recording and playback technology involved in sound design.
Recording
The process of capturing an analog audio signal and converting it to a digital format
is done with an analog-to-digital convertor (ADC). This is a piece of hardware that
measures electrical input and records in binary format. The fidelity of the conversion
process is dictated by several factors: the sample rate, the word length, and com-
pression.
The sample rate
The frequency at which the ADC measures the level of the analog wave is called the
sample rate. The higher the sampling rate the higher the upper cutoff frequency of
the digitized audio signal. Sample rates are measured in frequency of samples per
second; the higher the frequency, the better the audio quality.
