Thanks again all, for the compliments.
Let me tell you, the additional open space I now have is just magical for the Vistas, especially compared with what room situation I had before (see original pics at begining of thread). But, as we all know, or will find out eventually, there is no "perfect" room and I will still be tweaking room and settings 'till the end of time.
The first tool for this were the acoustic panels. I'll post up eventually how and what on the DIY section. basically, they did cut down on bass when deployed in the corners and eliminate the hot reflective spot in their current position behind the speakers. This, as well as covering the plasma display broadens the soundstage in a very discernable manner.
As you can see in the photos, the right speaker sound is re-inforced by it's 4' proximity to the right hand wall. The left speaker has 14' of clearance to the corner before interacting with the left wall. The initial result, with the acoustic panels in their current positions, is the soundstage expanding all the way to the right wall and being biased that direction overall. There is also a highly reflective flush panel door to the left 4' outboard on the rear wall. (more on this further on).
This is where the Behringer DEQ2496 comes in.
This digital equalized/processor brings much much more to the table than it takes from the system, and I recomend the relatively small investment for anyone.
My original goal for a stereo was one of purity of components, i.e. no processing, no tone controls, nothig but straight source - switching - amplification - sound. I've since then come to my personal conclusion that this would also mean no walls, floor, or ceiling either, were I to achive sonic nirvana without any kind of correction.
The DEQ has 6 processing modules: Graphic EQ, Dynamic EQ, Parametric EQ, Feedback destroyer, Width, and Compressor/Expander. Dealing with the assymetry of my walls, I use the Width module.
Basically, this allows me to shift the overall soundstage left or right, with or without any common mono signals following the general direction or not. It also allows the overall apparent width of the soundstage to be expanded or contracted to suit need. The perfect tool for any imperfect room.
I now have a beautiful soundstage, filling over 16' of width on an 8' speaker spread. Not to give credit entirely to the 2496, the tall acoustic panels play a major part. So did the aforementioned door on the rear wall, but negatively. What the expanded/ corrected soundstage produced there was a hot high frequency reflection. I didn't want to dampen the area, thus loosing the gained left hand stage so I covered the doorway with a pair of Slatted Bifold Closet doors for diffusion. Wow! What a good simple highly effective fix.
Next tweaks with the Behringer was the Auto EQ function in the Graphic EQ Module. It does auto eq, but overcompensates and is dependant on mike placement, with all the inherent node /null assosiated with positioning. I used the resulting settings as a guideline, reducing each band change by 75% or more for an acceptable and subtle difference. Next was the Parametric EQ module for further subtle tweaking. I've found reduction in levels here gives improvement over increasing levels, especially in the lower octaves.
There is massive potential for overkill with the DEQ2496 or any other like component, and the learning curve is daunting. It is even a pain to wire correctly (another forthcoming DIY thread) but as I said before, well, well worth any small detriment, whether real or imagined, that may be introduced by its inclusion. At its worst, it can demonstrate what non-invasive measures can be made through more traditional methods.
So That's where I'm at so far, more happy than not with the system. A small tweak here, a small tweak there maybe. The next major hurdle is to cobble up a decent FM antenna for the tuner.