More commonly known as Dolby Pro-Logic :)

You get a center, front left & right, and a rear channel decoded from the normal stereo channels. (the 1 rear channel is fed to both rear speakers)

Dolby 5.1 is indeed digital, from a DVD & Sky+ for example.
You get 5 independant channels:
Front left & right, center, rear left & right
and a seperate channel for the subwoofer (the .1)

Quadraphonic and Dolby Prologic surround sound are two different things. Quadraphonic has four completely independent audio channels in the same way stereo has two.
Surround sound via Prologic uses extra info embedded into a stereo pair, which allows a suitable decoder to steer the sound to the correct speaker(s).

Sorry, i did mean ProLogic - my brain can't have been working at the time.

:o :shrug: :wavey: Having a 5:surround system I find that audio through my ntl box is not true 5:surround..ESPECIALLY annoying when ordering a film that announces 5:sound. I can listen in super stereo only....Ntl need to update there boxes with 5:1 output capability..But will they?!!:shrug: :spin:
:wavey:

our digi box has l/r phono outs.. its a pace 4000 i think.

you're only going to get pro-logic via the tv though i think.

surround is damn good on the xbox though ;P

The best the NTL boxes are capable of is Dolby Prologic. This is 4 channel surround sound through a stereo connection. Dolby digital (for 5.1 surround sound) requires a digital connection, which is not present on our boxes.

Any film which is stereo, probably has a prologic surround soundtrack though, although the amp will need to be switched manually to Prologic mode as most Amps cannot automatically pick it up.

NTL should update the boxes though..

In what way should they update the boxes?
You mean replace them with boxes with coaxial or optical digital outs? For Sky you need to buy a £300 Sky + box in order to get Dolby Digital.
How many channels currently are available with dolby digital surround, not many. Just Sky movie channels I believe.

Still if u are a sound aficiendo then you would be listening to Dolby digital/DTS on your dvd's cos that what I do cos I know 9 out 10 times the best sounds are from the DVD format.

And you can get this quality from the sky sat feed on the sky movies channels with the right stb.

Pro logic takes the stero feed and sends all perfectly in phase signals to the centre speaker.

perfectly out of phase signals to the surround speakers and left only and right only signals to the relevant speaker.

Its a clever system really.

I think this 7.1 sound is getting a little excessive in terms of the number of speakers though.

Only the 300quid Sky + box has Dolby Digital outs.

Aye and I find VERY little justification forking out £300 on a sky box that seems to have the same warranty as the normal box unless someone tells me different.

Close proppin, this Sony stb does have them aswell :)

Can I have a job please :P

Nope go to the back of the queue. A number of Sky boxes have optical SPDIF outputs but they only give you stereo out (and hence Prologic). Sky will not allow anyone to give Dolby Digital outs on anything except the Sky + boxes.

:D

Sky got very upset at sony putting that on there AFAIR.

Actually, I do mean replace them with Sky + styles boxes with Digital Out. Then charge the user a higher rental because they are getting a more advanced box.

Possibly also upgrade Front Row to DD, as I believe NTL is a part owner of this channel..