Creating Surround Sound

[zenzen1]

Watching and listening to some of my VideoHits music DVDs, I notice that when the amp is set to Dolby ProLogic II, some tracks do exhibit surround sound quality, while others are definately coming from the front speaker only. What is the difference in these tracks, and is there some way I can modify the front-only tracks to be more surround sound ?

[jimmalenko]

I'm not up with the exact techie terminology in this case, but what I believe happens is that Dolby ProLogic 2 can take a 2ch source and output a quasi-6ch surround signal from it. I'd be investigating a couple of tracks that do appear to be surround as well as a couple that don't in something like GSpot (the latest beta should read VOBs/MPEG) and see if you can see any difference in the properties of the files as far as audio goes.

[guns1inger]

You may also find that some of the tracks have been mixed as Doby PL sources, which means that they were mixed down from from four channels and encoded (for want of a better term, as PL is an analogue process) and flagged as PL. This will enchance any effect to the rear channels as the PL decoder has more to go on.

As for being able to create more of a surround effect, there is little you can do without getting the masters. You can try tricks like removing the vocals (sometimes possible, but rarely completely successful) to create new rear signals, play with frequencies and timings etc. A lot of effort for potentially little to no benefit. If you do wish to pursue it, have a look through these guides to see if anything helps http://forum.doom9.org/showthread.php?t=83752

[offline]

zenzen1,

you should be able to set your PLII capable amp to "music mode". This will create a surround effect in music but is terrible for movies or TV. Just disable it when not listening to music.

Most fully certified Dolby ProLogic II capable amps have both a music and movie mode.