Quadraphonic (or Quadrophonic & sometimes Quadrasonic) sound – the most widely used early term for what is now called 4.0 surround sound – uses four channels in which speakers are positioned at the four corners of the listening space, reproducing signals that are (wholly or in part) independent of one another. Quadraphonic audio was the earliest consumer offering in surround sound. It was a commercial failure due to many technical problems and format incompatibilities. Quadraphonic audio formats were more expensive to produce than standard two-channel stereo. Playback required additional speakers and specially designed decoders and amplifiers.

The rise of home theatre products in the late 1980s and early 1990s brought multi-channel audio recording back to into popularity, although in new digitally based formats. Thousands of quadraphonic recordings were made during the 1970s, and some of these recordings have been reissued in modern surround sound formats such as DTS, Dolby Digital, DVD-Audio and Super Audio CD.

In 1967 the rock group Pink Floyd performed the first-ever surround-sound rock concert at “Games for May”, a lavish affair at London’s Queen Elizabeth Hall where the band debuted its custom-made quadraphonic speaker system. The control device they had made, the Azimuth Co-ordinator, is now displayed at London's Victoria and Albert Museum, as part of their Theatre Collections gallery.