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→Basic Principles
== Basic Principles ==
The most basic way to think of digital audio is like animation or video. By playing a number of individual "frames" quickly enough, it gives the appearance of motion. In the case of audio, the frames are called '''samples'''. Unlike video, however, digital audio is not an illusion - the digital representation of the sound is capable of storing all the information contained in and can be converted back into required to reproduce identical sound waveswithin a given frequency range, at least theoretically.
The amount of information a digital audio signal can represent is determined by the ''bit depth '' and the ''sample rate''. '''Bit depth''' is the number of bits per sample. Each sample represents the ''amplitude'' of the sound wave at that point in time. The higher the bit-depth, the more distinct values are possible for each sample, allowing more and more accuracy in recording. If the bit depth is significantly low, the values for each sample will be quite "off" from the analog wave. When such digital audio is converted back to analog, the resulting waveform will have a significant difference from the original. This is called '''quantization distortion''', and it can result in increased noise and added frequencies in addition to simply loss of fidelity. Sometimes this effect is used purposefully (usually in electronic music), referred to as ''bitcrushing''.
The number of samples per unit of time is called the '''sample rate''', typically represented in kHz, which is the number of thousand samples per second. The sample rate determines the highest frequency that can be accurately represented, which is called the '''Nyquist frequency''', occurring at half the sample rate. With a 44.1 kHz rate, the highest-representable frequency is 22.05 kHz, which is roughly the maximum frequency that humans are capable of hearing. Typical depth/rate values are 16-bit/44.1 kHz (used on typical consumer CD's) and 24-bit/96 kHz (for commercial recording). Modern commercial hardware even supports up to 192 kHz, and some devices may operate at much higher rates in order to reproduce physical processes whose operation may affect lower-pitched, audible audio frequencies.