Dolby Laboratories

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"Dolby" redirects here. "Dolby" may also refer to the engineer Ray Dolby or the musician Thomas Dolby
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Dolby Laboratories, Inc. (Dolby Labs) (NYSE: DLB) is an American-based company specializing in audio compression and reproduction.

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[edit] History

Dolby Labs was founded by Ray Dolby in England in 1965. He moved the company to the United States in 1976. The first product he made was Type A Dolby Noise Reduction, a simple compander. One of the features that set Dolby's compander apart was that it treated only the quiet sounds that would be masked by tape noise. Dolby marketed the product to record companies.

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 B-type in 1968.

Dolby did not manufacture consumer products outright; it licensed the technologies to consumer electronics manufacturers.

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

Upon investigation, Dolby found that many of the limitations in optical sound stemmed directly from its significantly high background noise. To filter this noise, the high-frequency response of theatre playback systems was deliberately curtailed. . . To make matters worse, to increase dialogue intelligibility over such systems, sound mixers were recording soundtracks with so much high-frequency pre-emphasis that high distortion resulted.

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). In less than ten years, 6,000 cinemas worldwide were equipped to use Dolby sound. Dolby reworked the system slightly for home use and introduced Dolby Surround and Dolby Pro Logic.

Dolby developed a digital surround sound compression scheme for the cinema. Dolby Stereo Digital (now simply called Dolby Digital) was first featured on the 1992 film Batman Returns. Introduced to the home theater market as Dolby AC-3 with the 1995 laserdisc release of Clear and Present Danger, the format did not become widespread in the consumer market, partly because of extra hardware that was necessary to make use of it, until it was adopted as part of the DVD specification. Dolby Digital is now found in the HDTV (ATSC) standard of the USA, DVD players, and many satellite-TV and cable-TV receivers.

On February 17, 2005, the company became public, offering stock for sale on the New York Stock Exchange under the symbol DLB.

On March 15, 2005, Dolby celebrated forty years of enhancing entertainment at the ShoWest 2005 Festival in San Francisco.

[edit] Technologies

  • Dolby Analog SR or simply Dolby SR (Spectral Recording) is a professional four-channel noise reduction system in use since 1986, which improves the dynamic range of analog recordings and transmissions by as much as 25 dB. Dolby SR is utilized by recording and postproduction engineers, broadcasters, and other audio professionals. It is also the benchmark in analog film sound, being included today on nearly all 35 mm film prints. On films with digital soundtracks, the SR track is used in cinemas not equipped for digital playback, and it serves as a backup in case of problems with the digital track.
  • Dolby FM A noise reduction system for FM broadcast radio. Dolby FM used Dolby B, combined with 20 microsecond pre-emphasis. This system integrated into a small number of receivers, and was used by a few radio stations in the late 1970's and early 1980's. The system is no longer used, however.
  • Dolby Digital (AC-3) delivers digital audio via six discrete channels (referred to as "5.1"). The three front channels (Left/Center/Right) deliver crisp, clean dialogue and accurate placement of on-screen sounds, while twin surround channels (Left Surround/Right Surround) wrap around the audience and immerse them in the action. The LFE (Low-Frequency Effects) channel delivers real impact for explosions and other effects that can, literally, be felt as well as heard. Used in DVDs and cinemas and on digital satellite (DBS), cable, and DTV and HDTV terrestrial services. It can also be used to deliver 5.1 surround radio services.
    • Dolby Digital Surround EX introduces a center rear channel to the 5.1 playback format of Dolby Digital. It is matrixed out of the rear left and right channels, and so does not create true 6.1 sound.
    • Dolby Digital Plus is an audio codec based on and compatible with Dolby Digital, but more advanced. The DVD Forum has selected Dolby Digital Plus as a standard audio format for HD DVD video. Dolby Digital Plus can also be applied to limited bandwidth environments such as broadcast television.
  • Dolby-E selected hardware.
    Enlarge
    Dolby-E selected hardware.
    Dolby E is a professional coding system optimized for the distribution of surround and multichannel audio through two-channel postproduction and broadcasting infrastructures, or for recording surround audio on two audio tracks of conventional digital video tapes, video servers, communication links, switchers, and routers. The Dolby E signal does not reach viewers at home. It is decoded back to baseband audio just prior to the final DTV transmission and then re-encoded into the final audio format specified by the various DTV emission systems.
  • Dolby Headphone is technology that allows for simulated 5.1 surround sound in a standard pair of headphones.
  • Dolby HX Pro Single-ended system used on high-end tape recorders to increase headroom. The recording bias is varied with respect to the high frequency component of the signal being recorded. It does nothing to the actual audio that's being recorded, and doesn't require a special decoder. Any HX Pro recorded tape will have, in theory, better sound on any deck.
  • Dolby Stereo or simply Dolby Analog is the original analog optical technology developed for 35 mm prints and is encoded with four sound channels: Left/Center/Right (which are located behind the screen) and Surround (which is heard over speakers on the sides and rear of the theatre) for ambient sound and special effects.
  • Dolby TrueHD is Dolby's next generation lossless coding technology. It offers bit-for-bit sound reproduction identical to the studio master. Over seven full-range 24-bit/96kHz discrete channels are supported (plus a LFE channel,making it 7.1 surround) along with the HDMI interface. It has been selected as the mandatory format for HD DVD and as an optional format for Blu-ray Disc. Theoretically, Dolby True HD can support more channels, but this number has been limited to 8 for HD DVD and Blu-Ray.

[edit] See also

[edit] External links

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