By introducing an additional rear surround audio channel, Dolby® Digital Surround EX™ takes the Dolby Digital 5.1-channel setup one step further, clarifying audio effects that pan from front to back, and creating a more enveloping surround sound experience.
Adds a center rear channel to the Dolby Digital 5.1 system for increased cinema realism
Supports 6.1-channel home audio playback
Enables Dolby Digital Surround EX soundtracks on DVDs to automatically activate EX decoding in a compatibly equipped EX receiver or preamp/processor via a digital flag contained in the bitstream
Includes backward compatibility with any Dolby Digital 5.1 cinema installation and millions of existing home playback units
Dolby Digital Surround EX adds a third surround channel to the Dolby Digital 5.1 cinema audio format, enabling more precise sound placement, exciting special effects, and a more realistic audio experience.
In the cinema, rear-wall surround speakers located directly behind the audience reproduce the additional Surround EX channel, while the Left and Right Surround channels are reproduced by speakers located on the side walls. Home theater setups employ one or two back surround speakers for the additional EX channel.
Even if a cinema or home theater system is not equipped with the extra Surround EX rear speakers, the traditional Left and Right Surround channels fill in. This enables content encoded in Dolby Digital Surround EX to be backward-compatible with the thousands of cinemas and millions of homes worldwide that are equipped with 5.1-channel Dolby Digital decoding.
The cinema versions of feature films originally released in Dolby Digital Surround EX carry the matrix-encoded extra surround audio channel in subsequent DVD releases as well as in 5.1-channel digital satellite and TV broadcasts.
For home theater systems with a receiver or preamp/processor with Dolby Digital EX decoding and speakers to support 6.1-channel audio playback, Surround EX soundtracks are heard as they were intended, with increased realism created by the extra surround channel. As the extra channel is matrix-encoded into the Left and Right Surround channels and derived during production from natural cues in the soundtrack, no sonic information is lost in regular 5.1-channel Dolby Digital playback.
Current Dolby Digital Surround EX soundtracks contain a digital flag that can automatically activate the EX decoding in a receiver or preamp/processor. For titles released prior to late 2001, EX decoding must be turned on manually.