Dolby Stereo (or Dolby Analog) was the original analog optical technology developed by Dolby Laboratories for 35 mm prints in 1976.

It not only carried left and right tracks for stereophonic sound, but also a third center channel, and a fourth surround channel (which is heard over speakers on the sides and rear of the theater) for ambient sound and special effects. This yields a total of four sound channels, in the physical track space previously allocated for just one mono optical channel. Dolby also incorporated its A-Type noise reduction into the Dolby Stereo process.

The original Dolby Stereo was first used on the 1975 Ken Russell film Lisztomania, in a 3-channel LCR configuration. The first film to be mixed in Dolby Stereo and to utilize the surround channel was 1977's Star Wars, and the success of that film did much to encourage movie theaters to convert to the 4-channel LCRS speaker configuration. Dolby Stereo was displaced in 35 mm motion picture exhibition by the Dolby SR format in the mid-1980s.

Dolby Surround is the marketing name for the consumer implementation of this audio format, the term is not applicable to cinema.

Dolby Stereo 70 mm Six Track refers to a different 6-channel analog magnetic recording system developed for 70 mm prints in 1976. It adapted the original Todd-AO system of 5 front channels and one surround by adding Dolby A noise reduction and replacing the extra left and right channels with twin LFE channels. The system was later modified to use Dolby SR noise reduction and split surrounds, giving the modern 5.1 channel allocation retained today by Dolby Digital. Film sound production

Dolby Stereo