This article discusses the basics of Dolby Digital.
What is Dolby Digital?
Dolby Digital is an advanced form of digital audio coding that makes it possible to store and transmit high-quality digital sound far more efficiently than was previously possible. First used in movie theaters in 1992, it is the result of decades of experience by Dolby Laboratories in developing signal processing systems that exploit the characteristics of human hearing.
What program sources deliver Dolby Digital audio?
Dolby Digital audio is available from laser discs, DVD-Video discs, DVD-ROM discs for computers, digital cable systems, direct broadcast satellite (DBS) systems, and digital broadcast TV (DTV). Discs are usually marked with the logo
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Can I hear Dolby Digital programs over a regular stereo or Dolby Surround Pro Logic system?
Yes, you can use most of the new Dolby Digital program sources with your current playback system, because they have Dolby Digital decoders built in to provide conventional analog stereo outputs. However, to experience the thrilling 5.1-channel surround sound used on many Dolby Digital programs, you typically need a separate unit, such as an A/V receiver, that incorporates a 5.1-channel Dolby Digital decoder.
What is “5.1-channel” Dolby Digital?
At the option of their producers, Dolby Digital programs can deliver surround sound with five discrete full-range channels— left, center, right, left surround, and right surround—plus a sixth channel for those powerful low frequency effects (LFE) that are felt more than heard in movie theaters. As it covers only about one-tenth the audible bandwidth of the other channels, LFE is referred to as a “.1” channel.
How does 5.1-channel Dolby Digital differ from Dolby Surround?
5.1-channel Dolby Digital provides two surround channels to Dolby Surround’s one for more precise localization of sounds and a more convincing, realistic ambience. Also, the surround channels cover the entire audible range (20–20,000 Hz), whereas the range of Dolby Surround’s single surround channel is limited to 7,000 Hz. This further heightens realism and gives sound mixers more creative freedom. In addition, Dolby Digital’s multiple discrete channels enable more sharply delineated spatial effects, and its “.1” LFE track makes it possible to reproduce low bass effects with stunning impact (twice as loud as the other channels).
How can I determine the soundtrack’s format?
