Clarence, as you might guess, this could be a fairly long story, but I'll summarize. When you're playing a 5.1 DVD use DD or DTS, whichever the disc has. When you're playing 2-channel material(e.g. CDs, FM, TV)don't use any direct, pure or 5 channel stereo mode. If your setup is 5.1 use DPLII to extract surround ambience sound contained within the 2 channels(in varying degrees)and steer it to the surrounds where it belongs. Experiment with the center width and dimension adjustments available with DPLII to try to improve the effect.
