Decided to revisit this thread after further tweeks: Unplugged the bass management completely. MINOR repositioning of left speaker as toe-in was about 1/16" off. MORE bass treatment in front corners, swapped speaker cable back to my old Kimber 8TC (black & blue version)
1/48th octave sweep:
1/3rd octave:
The dip at 55 hz is much better and disappears when using 1/3rd octave sweep.
Overall, the soundstage is a bit better with regard to both focus and depth, but I think my vocals are a bit worse
- a bit too "chesty" so to speak.
.......the search goes on.