Quadraphonic sound uses four channels to output sound; right front, left front,
right rear, and left rear. The goal of a quadraphonic sound system is to
reproduce sounds in both the front and back of the listener, which simulates 360-degree sound. Quadraphonic sound became the more common and popular choice in
the late 1950s to early 1960s versus Four Channel Discrete
which was also available during that time.
New Adventures in Hi-Fi This "Hi-Fi & Computer" audio article cuts through the techbabble and tells the story of multi-channel audio, and details the latest 'high resolution' surround sound formats.
Surround Sound Past, Present, and Future (PDF) A history of multichannel audio from mag stripe to Dolby Digital. The first commercially successful multichannel sound formats were developed in the early 1950s for the cinema. At the time, stereophonic sound, a concept new to the public, was heavily promoted along with new wide-screen formats by a film industry feeling threatened by the rapid growth of television.
