You are right about the speakers being too close to the back wall. All the articles including the cardas method are clear on that, but so is my sweetheart : " Not an inch more, thatīs as far out as they can come !!"
So, I turned to the dark science of speaker placement, sound absorbers, forums, etc...
Some articles have suggested the use of sound diffusers. The whole idea being the reduction in reflected sound intensity at the listening position without prominent reflections. By reflecting the wave from the back side of the panel in all directions, strong reflections are eliminated and an assortment of time delays are produced, thereby distributing the interferences in the frequency spectrum. Here, speakers slanting at an angle are an added bonus.
Any ideas? Anybody used any diffusers to good effect?
Also there a train of thought out there that in certain cases absorption is not always good,
or too much of it.....
My head hurts from the differing opinions on acceptable time delays, and their detrimental effects, but some reflected sound is good , so the room is the final culprit and has to be tamed!! All identical rooms sound different due to the furniture present and its layout.
I think the little lady will summon the men in the white coats if I insist in being able to hear small differences as the speaker positions are tweaked!!!
Another funny thing is that when I asked for help in moving the speakers around and testing with music, my assistantīs position of choice was different from mine!