In the late 1960's, television broadcasting and viewing, and the sounds associated with it were in their infant stages. The ability to broadcast multiple tracks of information, particularly sound, was not available. HiFi Stereo for radio, and soon after, Stereo television was introduced in the mid 1970's. The result was a quality viewing/listening experience for live television. Dolby Laboratories introduced technology that would record in stereo in much the same way as broadcasting in stereo, so the birth of Home Theaters with huge, full surround sound came to be in the 1980's.

Dolby Laboratories' discovery made it possible for the advent of surround sound or, the encoding of sound information into a multi-track signal taken from the original movie or tv soundtrack. Sound processors made by Dolby could be paired with existing stereo receivers to achieve surround sound. Soon, stereo equipment makers incorporated Dolby technology in the design of their equipment, making surround sound affordable and available to all.

The Dolby Surround process involves encoding four channels of information--Front Left, Center, Front Right, and Rear Surround into a two channel signal. A decoding chip then decodes the four channels and sends them to the appropriate destination, the Left, Right, Rear, and Phantom Center (center channel is derived from the L/R front channels).

The result of Dolby Surround mixing is a more balanced listening environment in which the main sounds derive from the left and right channels, the vocal or dialog emanates from the center phantom channel, and the ambience or effects information comes in from behind the listener.

In musical recordings encoded with this process the sound has a more natural feel, with better acoustical cues. In movie soundtracks the sensation of sounds moving from front to rear and left to right adds more realism to the viewing/listening experience by placing the viewer in the action. Dolby Surround is easily useful in both musical and film sound recording, and will be a mainstay in home theaters for many years to come.