Just moved into a new room.. The longest length of the room has a mirrored closet on one end which I assume is not great for sound to bounce off when mixing/monitoring. The wall not facing the mirrored door has a window on it, and the wall with nothing on it faces the wall with window.
I'm inclined to put the DAW against the wall with the window since the window would be above the speaker area- and then line the bare wall with some treatment. Unfortunately the mirrored closet door on the side stays but I can open it halfway to reduce reflection.
A mirror will reflect sound but not because it being a mirror (like reflecting light) but because it is a rigid/solid surface. Needless to say I would be inclined to face the other wall and turn the closet into a LARGE/DEEP bass trap.