A reference to the reproduction and transmission of sound stored in a digital format.

This includes CDs as well as any sound files stored on a computer. In contrast, the telephone system (but not ISDN) is based on an analog representation (system that represents changing values as continuously variable physical quantities) of sound.

In sound recording and reproduction systems, digital audio refers to a digital representation of the audio waveform for processing, storage or transmission. When analog sound waves are stored in digital form, each digital audio file can be decomposed into a series of samples.