What is Dolby Digital EX?
Dolby Digital EX For soundtracks, such as those on movies and DVDs, 5.1 means that the soundtracks are recorded with five main channels: left, centre, right, left surround, and right surround, plus a low-frequency effects (LFE) bass channel (called a “.1” channel because it covers only a fraction of the frequency range of the main channels). Some movie soundtracks use a variation on 5.1 called Dolby® Digital Surround EX™, which has now migrated via DVDs to home theatre. This format matrix encodes a third surround channel onto the left and right surround channels of 5.1 soundtracks, and may be decoded or not at the cinema’s or home listener’s option due to their inherent compatibility. Because the extra surround information is carried on the left and right surround channels, Dolby Digital Surround EX encoded soundtracks are still regarded as 5.1 soundtracks. With respect to home playback, the terms 5.1, 6.1, and 7.1 mean that there are five, six, or seven main speakers, plus a subwoofer
