I was wondering about the same thing yesterday -- whether the huge differences in sound quality I see from changing speaker placement or room treatment were typical, or (and you guys said it much more nicely) I was just wierd.
I went 5 years or more with a relatively crappy sounding system (the room, not the equipment), but I ended up not listening to music much either during that time. Not sure which was cause and which was effect -- the music just didn't sound very good, and started to bug my ears after a few minutes.
I may be more sensitive to first reflection signal than most, since even now I notice immediately if there's a bad reflection even if it takes me five minutes to figure out the bounces ie where the reflection is coming from.
The interesting thing is that some albums I had written off as "poor recordings, listen in the car only" now sound much better. As an example, the B.B. Gabor CD (local guy from the 80s) sounded like crap on both the HT system and the stereo system downstairs, but with all the treatments in place it now has that "raw" sound you associate with direct-to-disk recordings but nothing fatiguing at all.
The bass problems are at least partially my own fault -- I'm drawn to interesting architecture so tend to end up in challenging rooms. That said, the level of mid-bass clarity you can achieve through luck or treatment is incredible -- the M60s are finally starting to remind me of the $50K systems in $100K rooms I listened to during my misspent youth (forget drugs, my parents worried about me mugging old ladies to feed my audio habit).
Getting into specifics :
1. Mark - breaking the window out didn't occur to me but that's a great idea, will remember it for next time
2. It's possible I was starting further back (ie with poorer sound) than most people, since AFAICS most of you do think about first reflections when setting up your systems in the first place (eg putting speakers on the long wall so you can ignore most of them) and aren't above making little tweaks (wall hangings, carpet, strategically located pillow/chair) where needed.
3. After some more listening I realized that the bass build-up in the bedroom *was* substantially reduced after all -- there was still a lot of bass there but almost as much bass out in the living room, so it turns out that moving one speaker had a huge effect on how the room was energized.
4. Decided there was actually too much bass with the new layout so experimented with speaker distance from the wall. First pulled them out ~5 inches and that seemed to reduce the bass too much, so pushed them back in a couple of inches and now it seems just right.
There's still a freaky amount of bass relative to what I've been hearing for the last 5+ years but the response seems pretty even, at least as far as I can judge by listening to bass notes walking up and down the scale.
My impression has been that when people buy Axioms and end up listening to all their recordings again it's because of the much-improved midrange clarity, but now I'm in the weird situation of wanting to go through every recording again and listen to all the bass lines I haven't heard before.
