Surround sound is a technique for enriching the sound reproduction quality of an audio source with additional audio channels from speakers that surround the listener (surround channels), providing sound from a 360° radius in the horizontal plane (2D) as opposed to "screen channels" (centre, [front] left, and [front] right) originating only from the listener's forward arc.
It is characterized by a listener location where the audio effects work best and present a fixed or forward perspective of the sound field to the listener at this location. The technique enhances the perception of sound specialization by exploiting sound localization; a listener's ability to identify the location or origin of a detected sound in direction and distance. Typically this is achieved by using multiple discrete audio channels routed to an array of loudspeakers.
There is a variety of surround sound based formats and techniques, varying in reproduction and recording methods along with the number and positioning of additional channels.