Solved!!! Thanks to help from the Shack. Experiments with location helped a little, but as I said, choices were limited. Then, I tried changing MY position! Turns out that my favorite seat is the worst in the house. The massive 35Hz peak turned out to be not much of a peak at all. My seat had a massive null at the bottom end, and flipping the phase took out the dip in the 45Hz region. Now the BFD gets me the graph below. Will experiment further in the future to go flatter, and/or try a house curve. For now, though, a whole new world! firing up Tron Legacy quickly confirms the change. Thanks again everyone!