A friend e-mailed me asking if this could be done. I told him I would ask the experts: I know I am going to have to worry about impedance matching, but do you think I can do the following? Two inputs (A and B) into my 4x12 with a three-way toggle switch. Position 1: All four speakers only input A. Position 2: Two speakers input from A, other two from B. Position 3: All four speakers only input B.