Home Cinema Sound Formats

Dolby Digital 5.1 Digital surround sound available on all home cinema packages. Uses five discrete channels of digital sound and a separate subwoofer channel (the ‘.1’ in 5.1)

Dolby Digital EX Updated version of Dolby Digital 5.1. Includes a third non-discrete rear-speaker channel to enable you to add one or two extra rear ‘centre’ speakers.

DTS 5.1 Rival to Dolby Digital 5.1, now included on many DVD films. More musical than Dolby Digital

DTS ES Matrix 6.1 DTS rival to Dolby EX

DTS ES Discrete 6.1 Ups the ante on Matrix 6.1 and Dolby Digital EX by including a discrete channel for centre-rear effects. In other words, this is true 6.1- channel surround

Dolby Pro-Logic Analogue surround processing that takes Dolby Surround-encoded stereo signal from TV broadcasts or VHS videos, and turns it into surround sound. Only the front stereo speakers boast discrete surround sound here, with centre speaker and mono rears being derived from the stereo signal

Dolby Pro-Logic II A soupedup version of Pro-Logic, this uses processing jiggery-pokery to make the non-discrete analogue surround sound more like Dolby Digital 5.1

Dolby Surround Most television programmes carry this additional, analogue surroundsound signal, which can be decoded by home cinema systems into Pro-Logic I or II

http://www.hdtvorg.co.uk/technology/home_cinema_sound_formats.htm