Thanks for the compliment AVRat. Yes, my PB12-NSD is sitting behind the screen (on a sand filled box at stage level) between center and FR speaker.
It's actually performing pretty nicely. I'm sure that what I did with bass traps is helping immensely. With the size of the sub, I was pretty limited on location options so did what I could with treatments to mitigate any nasties due to placement constraints. Following is a sweep with REW on just the sub from MLP:
I'm working (very part time) on getting a null figured out in my crossover region, and also considering getting another sub this year with the goal of placing behind screen as well on left side.