I have a room which is 13ft by 20ft. I have a 7ft wide projector screen in the middle of one of the 20ft long walls with the front speakers just either side of it. It would be convenient if the rear speakers were at either end of the opposite wall (i.e. 20 ft apart) and possibly wall mounted. Would such an arrangement work or would I end up with a 'weird' sound stage? What would be the best rear speakers to use, bipolar, dipolar or normal? The system would be used for film playback more than music. Nigel.