Dolby SR

The Dolby SR (Spectral Recording) noise reduction format was developed by Dolby Laboratories and has been in common use in professional audio since 1986 and in cinema audio since the late 1980s. It is a revised version of Dolby's earlier formats, combining aspects of Dolby A, B and C (e.g., sliding band and fixed band companders) to improve the dynamic range (i.e., the range in decibels between peak level and noise floor) of analogue recordings and transmissions by as much as 25 dB.

Dolby SR is used in many modern professional audio analogue (i.e., tape) recordings by recording and postproduction engineers, broadcasters, and other audio professionals. It is used as the optical analog format on almost all 35mm film release prints, and is always the accompanying optical analog format when Dolby Digital is present.

Dolby SR was originally implemented in Dolby's Cat.280 card, which was pin-compatible with the Cat.22 A-type noise reduction card. Thus, devices that took the Cat. 22 card could be upgraded from A to SR by replacing the Cat. 22 with the Cat. 280. The Cat.280 card functions in many devices including Dolby's Model 361 frame. Some Dolby Cinema processors require a special version, the Cat.280T, which functions for decoding (playback) only.

Dolby Laboratories

Dolby Laboratories, Inc., often shortened to Dolby Labs, is an American company specializing in audio noise reduction and audio encoding/compression. Dolby licenses its technologies to consumer electronics manufacturers.

History

Dolby Labs was founded by American Ray Dolby (1933-2013) in the United Kingdom in 1965. He moved the company to the United States (San Francisco, California) in 1967. The first product Dolby Labs produced was the Dolby 301 unit which incorporated Type A Dolby Noise Reduction, a compander based noise reduction system. These units were intended for use in professional recording studios.

Dolby was persuaded by Henry Kloss of KLH to manufacture a consumer version of his noise reduction. Dolby worked more on companding systems and introduced Type B in 1968.

Dolby also sought to improve film sound. As the corporation's history explains:

The first film with Dolby sound was A Clockwork Orange (1971), which used Dolby noise reduction on all pre-mixes and masters, but a conventional optical sound track on release prints. Callan (1974) was the first film with a Dolby-encoded optical soundtrack. In 1975 Dolby released Dolby Stereo, which included a noise reduction system in addition to more audio channels (Dolby Stereo could actually contain additional center and surround channels matrixed from the left and right). The first film with a Dolby-encoded stereo optical soundtrack was Lisztomania (1975), although this only used an LCR (Left-Center-Right) encoding technique. The first true LCRS (Left-Center-Right-Surround) soundtrack was encoded on the movie A Star Is Born in 1976. In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby Stereo sound. Dolby reworked the system slightly for home use and introduced Dolby Surround, which only extracted a surround channel, and the more impressive Dolby Pro Logic, which was the domestic equivalent of the theatrical Dolby Stereo.

Dolby (disambiguation)

Dolby may refer to:

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