How much affect do room acoustics have as a function of SPL? What I mean is this, if I play my music in around 80 -85 db which is fairly loud, my system sounds pretty good. Now if I play the exact same piece of music between 85 and 90db, I find that highs and mids become really shrill and etchy sounding, less clear. I know my system is part of the blame for this but I also wonder if room acoustics plays a significant role in this. When people build dedicated HT rooms, does the acoustic treatment's effects hold constant across the entire volume range for a given system? Lets say we're using 90db efficient speakers and a 100wx5 or 6 amp/receiver just to narrow down some of the variables.