I read this paper on Steven Klein's website titled "Time to Rethink Bass Traps"
Here is a quote I found interesting:
"Monitoring with 5” or 6” woofers in a 20’ room with 12’ ceilings, it is a waste of money to buy bass traps. The speakers simply do not have the energy to excite problematic modal behavior."
My room is 21'x20' and although it has an 8' ceiling, that ceiling will be soft. The hard ceiling is actually the hipped roof which is 8' above the ceiling which would average out closer to 12' than 8'. Anyway I have a hard time believing his statement because I can play a tone and walk around my room and hear the modal peaks and nulls, and I can see it on the graphs.
Am I misunderstanding? He doesn't seem like a kook.