[88BlueTSiQuest]

5.1 is 5 discrete audio channels of sound. I guess I should step backwards to help out...

First there was Dolby Surround sound, which utilized 5 speakers. However, it was still just 2 channel audio, that had specific encoding to 'simulate' surround sound. It would run a mix of out of phase sound effects that would be 'mixed' back into phase to be played through the rear speakers, and any equal volume sounds would appear localized through the center speaker.

When Laser Disc was introduced, they were able to utilize more audio channels, so the first 'Dolby Digital', AC3, was implemented, which gave you 5 independant channels of surround. Where Dolby Surround was still only 2 channel, and could only play both rears at the same time, Dolby Digital now has control of each individual speaker, allowing for true sound directionality.

5.1 Surround merely added an LFE(Low Frequency Effects) channel for independant subwoofer control.

6.1 DTS Discrete is just how it sounds. 6 independant channels of sound with the .1 LFE channel(7 channels if you wish to count it like that).

Channels are:
Fronts - Left, Center, Right
Left and Right Surround Side
Center rear.
LFE.

7.1 is merely 5.1 channels of discrete sound, with the 6th and 7th speaker running mono and mixed off the 4th and 5th speakers in much the same way that the center channel speaker in the original Dolby Surround(2 channel) setup was used.

Channels are:
Fronts - Left, Center, Right.
Left and Right Surround Side.
Left and Right rear.
LFE.

Allthough there are technically more speakers in the 7.1 setup, the Rears are essentially just an extension of the Surrounds, and not a true independant channel. Most 7.1 receivers usually have the rears hardwired together in the receiver. This can be seen by looking at the rear of the receiver, and examining how to hook up a single rear speaker(usually Left Rear +, Right Rear -, or vice-versa). Most 7.1 Receivers are DTS-ES compatible, which is why a single rear hookup is listed.


Personally, I enjoy 6.1 DTS-ES Discrete much better than Dolby Digital mixes. Especially when the Center rear is actually utilized to it's fullest potential. 7.1 merely uses the rears for 'ambiance', and doesn't have the ability to make the rears directional at all, they merely try to use them to compliment the surround sides.