Still isn't exactly clear what that is, but I'll guess its a diffuser of some sort?
The intent was to build something symmetrical to add some diffusion to the rear wall of the theater. Since the distance from the rear wall to the seat is about 7-8', I added some absorption to eliminate any direct reflection back to listeners ears.
I wish that I could say "WOW" it sounds so much better, but that is not the case. I am sure that it is added some benefit though.