Need help determining next upgrade - 3rd ATTEMPT

I had a room similar to this at one time. It was not easy to set up but what worked for me was using the Audio Physics method of speaker placement. It may be worth looking up and trying out. Almarg has suggested similar points in his post. Unfortunately you do not have a long wall but the system can still work with some modification. Put the listening chair within a couple feet of the back wall. Heavily treat the back wall, preferably with 4" panels. Then try moving your speakers into the room. In my set up they were half any in, but I also found that by moving them back towards the front wall in small increments that a third of the way in worked pretty good as well.

Another method you could try if it is feasible with your space is to use an off axis diagonal set up. If you visit the Decware website there is some good information on how to set this up. If anything you'll learn a lot about speaker placement which is not a bad skill to have.

Realremo, I would agree with others to work on the room acoustics first before you start down the hardware path. There are acoustic panel sites that can provide guidance based on your room size and recommend the proper amount of room treatment. You don't need to spend a ton of money. Perhaps some bass corner traps, and first reflection acoustic panels.

IMO the 12x12 room could be the cause. Temporarily relocate the speakers/system to your largest room. This could help you pinpoint the problem. Does the smearing get worse with increased volume? If the smearing still occurs in a larger room(with increased volume) it's probably more equipment related then... cables/vibration control/power conditioning or even room acoustics.

OK I've shifted my system to the short wall of the room. It's actually 12'8 x 11'4, so this layout gives me more space behind the speakers, and a little more distance between speakers and listening position. I'm also ordering some 2" foam for the back wall. The sub is now in a corner bracketed by concrete foundation walls, the room is in the basement. Bass has tightened up. I think the soundstage has shrunken in width tho, because the system is on the short wall.

Clio, that audio physics website has a ton of good info, so thanks for that.