... and was far, far better than what I had before. There was no way I was going to improve it without doing serious treatments.
+1 on the first. I have also ht the serious treatments wall regarding bass in my concrete box (at least its not square).
I have no doubt that ear break-in occurs and that it take a fair amount of time. Over the first 6 months or so what sounded good to me changed considerably. At some point, the surrounds sounded better level matched where I couldn't 'hear' them. I went from running the sub 10+db hot to maybe 2db hot. I could start to recognize instruments and music where I was getting too much reflection from my room (yes Virginia the M80s can be bright
on some material in a higly reflective room).
As much as I talk about tweeking (I'm a propeller head at heart) I spend far more time listening and only tweek after I completely understand what I am tweeking.
Oh, and you need at least 6 subs.