How many sq feet of diffusion do I need?

Thank you Lowrider57. Yes, my room measurements are in feet. To be
honest, I think my system sounds very good but frankly I think I dont know
any better because I never had any room treatments. I had a company
come in and do some analysis of my room and they identified various
issues such as modes. Their total solution involves bass traps, absorption
on side walls and ceilings, and diffusion on the front wall. I didnt want to
commit to the entire package, preferring to take small incremental steps.

To answer you question, yes its a live room. I "think" the highs
are bit too harsh. And I have messed around quite a bit with my speaker
position. To me they sound best at their current position.

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?