Quadraphonic Sound: Early Four-Channel Audio Format

Quadraphonic sound refers to a four-channel audio reproduction format. It was introduced in the early 1970s as an attempt to create immersive listening. The system uses four discrete channels placed at the corners of a listening space. Various encoding and playback methods were developed, including matrix and discrete approaches. Commercial releases appeared on vinyl, tape, and later on CD formats. Adoption was limited due to high costs and competing technologies. The format eventually gave way to more flexible surround sound standards like Dolby Surround. Interest in quadraphonic sound has resurfaced among audiophiles and retro technology enthusiasts.