Originally Posted by Ocuriel
Would any of these do the trick, and are they the same as the ones being used as mentioned on above posts?
Yes, Dolby PLIIz includes PLIIx (same algorithm, except you're not using height speakers). So you're good to go with your receiver choice.
When you apply PLIIx to 5.1 material, the front channels aren't touched. 3 channels, 3 speakers, nothing to process. The processing happens only in the surround field, where the information in the 2 surround channels
is steered across your 4 surround speakers
. (Don't confuse channels with speakers.)
If you were listening to a properly laid out 5.1-speaker set-up, you would notice that sounds that were mixed to the left surround channel would be heard from the left surround speaker and sounds from the right surround channel would come from the right surround speaker. Sounds that are mixed to both surround channels would come from both surround speakers, creating a phantom image somewhere behind you. In order to hear that phantom image back there, you would have to be sitting exactly between the surround speakers. If you were sitting to the left or right, that image would collapse to the speaker near your side instead of appearing to come from behind you.
PLIIx extracts those particular sounds and sends them to the speakers behind you. Now, no matter where you sit, those sounds always appear to come from behind you. Since they're coming from actual speakers behind you, they won't collapse to the nearest side speaker. Same directionality as before, just made more stable, especially for listeners sitting outside the sweet spot. One of the advantage of playing 5.1 material on a 7.1-speaker set-up.