Speaker sound differences?

I've posed this question before but I thought I'd ask again. I find my right speaker a little tinnier or bright sounding than the left speaker. Is this normal or could it be a crossover problem with my Hales T5's. The difference is not noticable from my listening position but is noticable if close up to each speaker. Could this be a room issue even though my room is a perfect rectangle being 17'x13'x9'. I do have windows on the right side but they are covered with blankets and the left side of the room has another room on the other side of the wall. As well there is a door on the left side of the room at the back of the left wall. If I change the channels of the amp to the opposite speakers I hear the difference between the right and left channel of the amp(PasX250)from speaker to speaker switch and the difference is very slight but the character of the slightly thinner sounding right speaker remains. I would try switching the speakers themselves but the effort to get the speakers properly placed to begin with is something I don't want to play with. Could the windows on the right side of the room cause the thinner sound of the right speaker? I notice that the entire speaker sounds thinner including the bass but it is only noticable if looking for this difference right up close at the speakers. The woofers will pump the same(so it looks like) but the left speaker goes a bit lower in bass if looking for this phenomenon.The left speaker is generally fuller sounding all around. It is subtle however. I guess my question is Is it possible I have a crossover problem or inbalance with my Hales or is it more likely a room issue or even an amp related issue? Has any one heard of speakers doing what mine do as a result of inbalanced crossovers? I'm concerned as I will never find replacement crossovers for Hales speakers. Any advice would be highly appreciated as it is of concern to me . I should mention that I got a Hydra 6 to replace my PS Audio P500 and the difference between speakers is less noticable. If I play straight test tones between the speakers they sound even. This phenomenon is only noticable with music. Thanks for your help.