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SDDS

What is SDDS?

Sony Dynamic Digital Sound® (SDDS®), is the film industry's most advanced digital sound format. In developing SDDS, Sony applied its experience in professional and home audio to give the movie-going audience the highest quality sound presentation. SDDS is provided by Sony Cinema Products Corporation (SCPC) a Sony Electronics company which has the mission of supplying the cinema exhibition industry with advanced technologies and products. SCPC is headquartered in Culver City, California, (within the Los Angeles area) with a European office located in London, England.

Why did Sony develop SDDS?

A central part of Sony's business is to improve the way people listen to and enjoy sound. Sony has developed the best in audio recording technology with innovations such as the compact cassette, the audio tape and the compact disc. In recent years, Sony has expanded its business into the production of quality software for both music and film. With Sony's venture into Hollywood and its commitment to the motion picture industry, Sony has also chosen to apply its expertise in digital audio to improving the cinema experience.

How is SDDS different from other digital film sound formats?

While all digital soundtrack formats offer audible improvement over the analog formats of a few years ago, the SDDS system is superior in its ability to deliver the highest quality. SDDS excels over other formats in several areas; the number of channels, its built-in digital redundancy, and its audio coding technique. While the other formats have a maximum capacity of six channels, SDDS can accommodate eight. SDDS uses a data reduction technique known as ATRAC that delivers excellent quality while keeping each recording channel truly discrete. When these elements are brought together under the renowned Sony name, the audience hears a presentation that cannot be duplicated by any other digital format.

Why eight channels and how are they used?

The expanded loudspeaker configuration has its roots in the widescreen Cinerama and 70mm formats of the 1950 and 1960s. These used five full range loudspeakers behind the screen and a single surround channel giving the audience six channels. Variations economized by not using the Left Center (LC) and Right Center (RC) screen loudspeakers but used their film tracks for split or stereo surrounds (LS and RS). Although the addition of the stereo surround and sub-woofer channels was an improvement, the loss of the LC and RC screen loudspeakers created problems for sound engineers who wanted to create a sweeping sound to fill the larger screens. Today, SDDS with five screen loudspeakers, two surround channels, and a sub-woofer channel takes the best of 70mm sound and returns the missing LC and RC loudspeakers.

What is the difference between SDDS and THX?

SDDS is a digital soundtrack format, which involves both the recording in the studio and playback of digital sound in the theatre. THX® is a certification program and consulting service that advises theaters primarily on quality amplifiers, loudspeakers, and proper room acoustics. THX certification is independent of the film's format. Theatres who conform to specifications and recommendations by THX use their logo to identify conformance to these standards. Any manufacturer's sound system that conforms to THX standards is frequently identified as a THX Sound System.

Does SDDS have a consumer equivalent for DVD and Laserdisc?

SDDS is a professional format intended only for the motion picture theatres. Its eight-channel configuration, with five loudspeakers behind the screen, would be inappropriate for smaller 5.1 channel home systems. Sony intends to keep SDDS as an exclusive experience for the movie theatre. In fact, both competing formats put the exhibitor at a disadvantage in that their home versions have higher performance than their professional systems. While the DVD specifications have provided a designation for a potential SDDS bit stream, Sony has no current plans to develop a consumer version of SDDS.

What about Surround EX?

Surround EX is a joint development of Dolby and THX that adds a Back Surround channel by incorporating an analog matrix decoder with the Left Surround and Right Surround tracks. Technically, Surround EX is not a new film format but rather a minimal enhancement to the existing 5.1 channel loudspeaker configuration. The analog matrix technique, much like Dolby's Pro Logic for consumers, is compatible with all digital formats including SDDS. Dolby and other companies have announced external analog matrix decoders that can be added to any existing digital system.

SCPC is working with filmmakers to better define what they would like in surround channels. If it is apparent that additional channels are desired, Sony will likely incorporate surround enhancements in future products. Sony feels that rather than an analog matrix system, the industry would benefit from a fully discrete and digital approach.

Is there a version of SDDS for 70mm and special venue applications?

For many years, the use of 70mm has been winding down due to its high print and handling costs, however an occasional film is released in 70MM. Recently there has been discussion of a limited return to 70MM for special venue formats and for larger screens. SCPC is closely following the trend in 70MM releases and is evaluating if a dedicated 70mm SDDS format is justified.

Why are directors and sound designers insisting on SDDS releases?

The filmmaking community is insisting on SDDS because of its sound quality. Filmmakers have always been driven to improve the look and sound of their creative efforts. Just as cinematographers seek out better lenses and better photographic processes, the sound designers want to use the best technology to reproduce their work.