I'm still a bit confused about the exact math I would need to run to understand the max SPL in my room (which is just around 5000 cubic feet, so it's on the border between large and extreme). How are boundaries taken into account? If corners gives such a nice SPL boost, would they still have some kind of disadvantage, say more distortion or less flat response? In my room the corner actually gave the flattest response (not flat, but other locations were worse) along with significantly higher SPL (at least according to Audyssey calibration trims chosen for each location). What about multiple subs? For example, would a pair of Pb-2000 (or at least a pair of Pb-2000 Pro) classify as extreme together?
Would all "extreme" level subwoofers let me play reference levels in the bass in worst-case scenario? Or is it calculated based on a more realistic scenario? Not that I need reference levels, but I do listen at -18db and use DEQ so lowest frequencies are more like -9db from reference, and might need some more headroom for maybe listening a bit louder or boosting the bass a bit to taste or just for Audyssey headroom. I want to know if the data here is enough to figure out whether my system can obtain said levels, and if not, what system could, as well as what levels I can safely play with what I have or if I spend X money.
Would there still be some difference in sound quality other than just the measured SPL? Would it be significant? As in, would a subwoofer with max 110db play 100db "cleaner" than a subwoofer that maxes out at 100db?
Also I guess I also need to figure out how much SPL my speakers can handle. Is there a simple way to measure that in REW?
From here I understand that measuring subwoofer distortion at high SPL with umik won't work, but maybe there is an alternative trick to find the "local/personal" limit by measurement/experiment?