My answer may have been inappropriate due to my misunderstanding. IMHO, great depth of image (pin point imaging) can exist only when you have achieved optimum resolution in equipment, room and set up. (My biggest improvement in depth of image came with boxes with SOTA tweeters).
Diffusion could help your sound if placed on the wall behind your chair. Although I doubt it, it might even help on the side walls as well. So could some deadening materiel. The frequencies that bring depth of image to life are the high frequencies so you can (sorta) replicate the effects of using expensive materiels by simply hanging some heavy materiels on the wall(s) temporarily and see what happens. If you get no change at all in depth of image then you can figure you are barking up the wrong tree.
FWIW. It is hard to fine tune a system over the internet. :-)
Diffusion could help your sound if placed on the wall behind your chair. Although I doubt it, it might even help on the side walls as well. So could some deadening materiel. The frequencies that bring depth of image to life are the high frequencies so you can (sorta) replicate the effects of using expensive materiels by simply hanging some heavy materiels on the wall(s) temporarily and see what happens. If you get no change at all in depth of image then you can figure you are barking up the wrong tree.
FWIW. It is hard to fine tune a system over the internet. :-)