Co-developed with Lucasfilm THX, Dolby Digital EX adds one or two matrixed rear center channels. Formerly "Dolby Digital Surround EX," the first film to use this enhanced version of Dolby Digital ...

A digital audio encoding system from Dolby that provides four channels. Derived from the Dolby Stereo technology used in movie theaters, Dolby Surround was introduced in the early 1980s for video ...