A family of techniques for compressing digital audio based on the human perception of sound (psychoacoustics). Perceptual audio coding eliminates quieter sounds that are not heard by most people. For example, when several musical instruments are playing simultaneously, depending on frequency and volume at any given moment, the sounds from one instrument can seem to cancel out the sounds of another. See
frequency masking,
temporal masking,
subband coding,
audio codec and
speech codec.