Stereophonic sound or, more commonly,
stereo, is a method of sound reproduction that creates an illusion of multi-directional audible perspective. This is usually achieved by using two or more independent
audio channels through a configuration of two or more
loudspeakers (or stereo
headphones) in such a way as to create the impression of sound heard from various directions, as in natural hearing. Thus the term "stereophonic" applies to so-called "
quadraphonic" and "
surround-sound" systems as well as the more common two-channel, two-speaker systems. It is often contrasted with
monophonic, or "mono" sound, where audio is heard as coming from one position, often centered in the sound field (analogous to a
visual field). Stereo sound is now common in entertainment systems such as broadcast radio and TV, recorded music and the cinema.
