How many sq feet of diffusion do I need?

Thanks everyone especially Lowrider57 for the kind words. I am a bit limited in what I can do in that room.

I can't treat 1st reflection points since my family needs access to the closet and window which are at these points.

I can't move the speakers away from the front wall more because the window and closet door cannot be accessed.

I don't think I need anything behind me because there is only a 1/3 height wall above which is open to our spacious family room and kitchen.

I guess my dilemma is I don't even know if I need room treatments. How would I know since I never had any treatments? All I know is everyone who has treatments says it's the single biggest improvement to their system.

It seems the two things people tend to agree on is larger rug and bass trapping to help clean up mids and highs. I guess I can start here but how would I know if I need more treatments? Maybe I should just screw it and continue to listen in ignorant bliss?

Not to flog a dead horse, but couldn't you hang one vertical panel on each side wall as seen in Krell_man's System photos. It looks like you have room for a panel to the left of the door or hang it on the door.
IMO, that would absorb some standing waves; your exposed side walls are causing major reflections which lead to increased brightness.
That's it from me, I'm not trying to sell you anything. lol.

Tommy,

RealTraps and GIK Acoustics, and probably others as well, have stands for their absorption panels. Then you can just move them when you need to.

Chuck

I would try absorption over diffusion. I believe an acoustic panel on each side wall, even if not ideally placed as to 1st reflection, and base traps in corners behind speakers would help. In addition, you will have done something which seems to be a need for you. Check out ATS Acoustics, I have made my own panels and base traps from their supplies.

I am still having fun experimenting with my listening room.
Regards, Mike