I have a feeling the spike at 120 is a crossover issue, 60-70 is normally an 8 foot ceiling, 40-50 (and if you had 9 foot ceilings) is the room size. So reflection point over your head and in front of you. Pull the speakers out from the walls, if only for listening. The suck out is REAL important.
WHY?, you’ll enjoy the un bloated bass, because you’ll volume DOWN.
You filled in the missing parts, you’ll see, MC was right on. Take care of the suck out and the bass will clean up.. Bass traps at 12" to 48" in all 4 corners, Not higher, not lower.. Both front and rear walls, dead center, do something, Drapes, kill the returning waves a bit...
EQ the rest. I use full blown DSP for bass management, nothing else 300 hz and below. PEQ, GEQ, slopes, threshold, phase...everything..
Above 300 hz all passive with high quality parts..
The slow decay rates are because the room is WAY to lively.. That is also why you have all the combing (dips, and actual valleys..)
Ricochet biscuit, comes to mind..:-)