@erik_squires
Thanks for the suggestion, Erik. I have been moving a lot of things around and mostly attending to frequency response. To place traps, I listened and measured around the room, and located traps where the peaks are highest. In some places, however, the peaks are *not* at the floor, and your suggestion helps remind me to consider that raising panels might help imaging even if frequency does not. Unlike some other posters here, this is my room to do as I wish with, and so anything which can be tried is fine with wife, family.
Are the (P) panels bass traps or diffusor/absorbers, by the way?