Definition: Dolby Digital EX is based on the technology already developed for Dolby Digital 5.1. This process adds a third surround channel that is placed directly behind the listener.
In other words, the listener has both a front center channel and, with Dolby Digital EX, a rear center channel. If you are losing count, the channels are labeled: Left Front, Center, Right Front, Surround Left, Surround Right, Subwoofer, with a Surround Back Center (6.1) or Surround Back Left and Surround Back Right (which would actually be a single channel - in terms of Dolby Digital EX decoding). A home theater receiver with a Dolby Digital EX decoder is required.
Also Known As: Dolby Digital 6.1