Quadraphonic sound

Quadraphonic sound uses four audio channels in which speakers are positioned at the four corners of a listening space. The system allows for the reproduction of sound signals that are (wholly or in part) independent of one another. It is an early form of what is now called surround sound.

Four-channel quadraphonic surround sound can be used to recreate the highly realistic effect of a three-dimensional live concert hall experience in the home. It can also be used to enhance the listener experience beyond the directional limitations of ordinary two-channel stereo sound. Quadraphonic audio was the earliest consumer product in surround sound. Since it was introduced to the public in the early 1970s, many thousands of quadraphonic recordings have been made.

Quadraphonic sound was a commercial failure when first introduced because of a variety of technical issues and format incompatibilities. Four-channel audio formats can be more expensive to produce than standard two-channel stereo. Playback requires additional speakers and amplifier channels. It may also require specially designed decoding equipment.