If you look at the before & after waterfall plots which were taken from one speaker in the center of the room. You will notice a ~50hz "lobe" in the before which is much smaller in the after. This is what I think is giving me the apparent reduction in "boominess."
I see the reduction. Still, usually a bass boom is at a higher frequency. I still think the issue at 75-80 is the more likely culprit. The energy excitation at 50 is reduced in time, but it was never very loud... 25+dB softer than the 80 Hz peak. That's like comparing a snap of your fingers to a shotgun blast.
The SPL at 50 Hz is so low that you won't hear much of a signal at that frequency at all. Your speakers are dropping audible response at that range, so it certainly wouldn't cause a "boom"
