For what it's worth, I have Theater 4's in a 4m x 6m room but set up along the long wall. they sound good. I'd be a little concerned that in a more square room you might have some standing wave issues and with the speakers closer to the corners you might have too much bass. I think Wayne Parham may probably want to comment here. Again FWIW, I'm helping a friend build a pair of 2 Pi's and will post some comments on how they turn out and sound in my system (Bottlehead Foreplay and Paramours).

Garland

This positioning arrangement does not apply to two π speakers. In that case, it is generally best to be less than 30o off axis horizontally from both speakers, with the angles equal. You should also strive to be on the vertical axis with the midwoofer. The sweet spot is smaller, and defined by a line where both these conditions are met. That's where they sound best.

G.