@OP While not necessarily the cause of your problem, you will get comb filtering from reflections from your sofa as well. So a throw on it will help as well. If you are hearing the problem within a foot of the speaker, check that it's not a resonance in the speaker itself - check that all the drive units are properly torqued.
Asymmetric Room
I have a semi treated asymmetric room & am getting some hash/glare from certain artists. I performed a frequency sweep from Qobuz using “Audio Line-Up Test Tones (Calibration Reference Check)”. I am getting a wavering tone in the 1khz and 1.25khz range.
chatGPT made several recommendations… speaker toe in, seating placement, ceiling treatment & treatment of the pool table on the left side (open area of the room). I can’t change seating position (large L shaped couch) & toe in had no effect. I very much prefer not to treat the ceiling (but will if I have to).
My system & room layout is loaded. Any recommendations would be appreciated. Thanks