One thing about the THX baffle wall you mentioned. I never really heard that term before so I looked it up on the THX website. It's like "Ding, ding, ding...that's what that was!" I remembered that the main auditorium at the UA Prestonwood had this thick insulation pad on the wall behind the screen. It was about 6 inches thick and was like very thick insulation. It was about the same size as the screen. You could only really see it when we did screen replacements. Other THX auditoriums had somewhat thinner ones. Prestonwood was odd because that main screen had originally been mounted flush with the wall when the theatre was built in 1980. The backscreen speakers were mounted in housings cut through the wall. When the THX upgrade was done, a false wall was created that mounted the screen. The speaker loft spanned the space betweeh the sceen and the back wall, which created the storage area below where the subs were. That mysterious pad looked weird just stuck to the back wall.
I really miss running those THX trailers. With the original 70 mm one we'd ramp the volume knob up full blast at the end when the house was full. And everyone would clap. It would rattle the drinks out at the concession stand.