I remember reading something a while ago that about how our brains do a good job of filtering out the specific signature a room gives to sound. I think Dr. Hsu said it.

To make an analogy, it's akin to wearing ski goggles. When you first put them on, everything looks decidely tinted. But then your eyes adjust over the period of a few minutes and everything looks normal again. When you take the goggles off at the end of the day, all the colors seem off again.