ABSTRACT
The first commercially successful multichannel sound formats were developed in the early 1950s for the cinema. At the time, stereophonic sound, as it was called, was heavily promoted along with new wide-screen formats by a film industry feeling threatened by the rapid growth of television. Unlike the two-channel format later adopted for home use because of limitations imposed by the phonograph record, film stereo sound started out with, and continues to use, a minimum of four channels.
