Dolby Digital#Dolby Digital EX
Dolby Digital EX is an extension of Dolby Digital multi-channel sound system and has been with the film Star Wars 1999: Episode I imagined.
Comes to 5.1 speakers in the Dolby Digital system / come on ( 6.1) or two ( 7.1) back surround channel / channels to play through one or two speakers accordingly / n
The signal of the sixth channel is encoded in the signal for the left and right surround channel (the signal corresponds to all colors that are identical in the left and right surround channel ), and decrypted using a special decoder. The coding is carried out, similarly to the encoding matrix of the analog Dolby Pro Logic, via phase encoding. This backward compatibility with Dolby Digital 5.1 is guaranteed.
The theatrical version works on the same principle and is run under the name " Dolby Digital Surround EX".
In a home theater 6.1 arrangement only makes sense when a very large distance between the left and right surround channel exists. Otherwise, the playback of the seventh channel ( Surround Center ) on the 5.1 arrangement ranges, with a phantom surround center is formed over the two surround speakers.