Whats the reason for having dark colors in a dedicated HT room?Science or asthetics?
It's so that when there is a bright scene the room walls don't reflect the light and distract one's eye from the screen. Scientifically dark surfaces reflect less light than lighter surfaces. So I guess it a combination of Science and Aesthetics. Flat black would be the best choice for a dedicated theater -- but not many wives would approve of that -- so aesthetically a maroon, dark green or deep blue color scheme is usually preferred.
