Computers represent an audio (sound) signal by a set of values (samples) obtained by repeatedly measuring (sampling) the signal. Each sample is stored as a string of bits. For example, suppose a 5-second audio signal was sampled at a rate of 44100 samples per second and each sample is represented by 16 bits. Then, the audio data size = 5 x 44100 x 16 = 3528000 bits = 441000 bytes. When the computer plays these samples at a rate of 44100 samples/second, they appear to the human ear as a real continuous sound. Methods (MP3 for example) have been developed so as to compress audio data so that they are represented using a fewer number of bits.
