I am looking for a sub to occupy 15 x 14 inches of floor space in a room corner limited by a fixed cabinet. Unfortunately, I cannot easily place a sub elsewhere. Can a ForceField sub be used positioned with the active driver pointed down and the radiator pointed toward a wall or into the room?

That's a new one!

I suppose you could position it with the active driver facing up (or down), feet against the wall (passive radiator needs flat surface below feet to form the slot loading that is part of the sub's design). That said, I am not sure of the long term implications for the driver, or if there would be any difference in performance from a "typical sub on the floor" installation.

Thanks again for your answer. Well, I purchased a Forcefield 4 and then built a small table (about 10 inches tall) with a hole cut out to allow the FF4's active driver to point down toward the floor and the passive radiator to point toward the back wall. I think it sounds fine and takes up very little floor space!

Cool idea, glad it worked out for you, enjoy!