Ken, don't use any movie mode(apparently what Jason really meant)on music, since it intentionally makes the center channel more prominent in order to help with movie dialog. Also don't use the all channel stereo mode, since all that does is duplicate the main channels in the surrounds, for more uniform sound all around the room for parties, etc. Still another set of modes to likely take a pass on are the "advanced" modes(Jazz Club, Beer Garden, Sportin' House, etc.)which add artificial reverb.
What to use on 2-channel music sources is DPLII Music, or Neo:6 Music, or maybe(not so obvious)Neural Surround, which also operates on regular 2-channel material in most receivers(I haven't checked the 84). Yes, better surround speakers will, of course, give you a better effect.
I never use a straight stereo mode on music, since I want processing which extracts the natural surround ambience from the front speakers and sends it to the surrounds where it belongs. I use DPLII Music generally(including adjustments of the dimension and center width settings), although I'm now also experimenting with the effect with Neural Surround.
