Original name for Dolby Digital EX.

THX Surround EX provides direct decoding of Dolby Digital EX and Dolby Digital soundtracks. It can also be used in tandem with DTS-ES, DTS, Dolby Pro Logic, or Pro Logic II decoding. In either case, THX Surround EX applies unique processing enhancements such as Cinema ReEqualization(tm), Decorrelation(tm) and Timbre Matching(tm) to increase the realism and impact of the home theater experience. THX Surround EX decoding is capable of producing 6.1-channel sound from any home theater source. With Dolby Digital EX and DTS-ES DVDs, the 6.1 channels are implicit in the soundtracks themselves (in the case of Dolby Digital EX DVDs, the back surround channel is matrixed in the left and right surround channels). With 4-channel (Dolby Surround) and 5.1-channel (Dolby Digital and DTS) sources, the extra channel(s) are derived using special THX processing. You'll need a receiver with 6-channel power (or a 5.1-channel receiver with an auxiliary amplifier or a powered speaker) to enjoy THX Surround EX's back surround channel.

Dolby Digital created Surround EX for movie theaters. THX Surround EX is the home theater version and it decodes a back surround channel signal from the left and right surround channels to create a 360-degree sound environment. EX encoded DVDs are required.

THX Surround EX features additional left and right surrounds Back channels on the basis of Dolby Digital 5.1 channels. The sound field enhances the sense of depth and smoothness of movement.

a home theatre surround format engaging an additional rear surround speaker, allowing for dramatic 360 degree surround sound. This technology made it's theatrical debut with the opening of Star Wars: Episode I The Phantom Menace.

Officially-licensed decoding system for Dolby Digital Surround EX software. Mode can also be applied to DTS-ES software. Usually uses two centre-rear channel speakers.

This is built to further extend Dolby Digital Surround EX (DD-EX). This could be considered a 7.1 channel system. As opposed to DD-EX, which has an added channel in the center rear, THX-EX puts 2 more channels in the rear, so there is a front left, front right, front center, listening position left, listening position right, rear left, rear right. It uses Dolby Digital 5.1 as a base and matrixes in the extra 2 channels into the rear channels similar in fashion to Dolby Pro-Logic and Matrixed Surround. It is going to be available exclusively in THX Ultra certified products.