Are both drivers on the Empire working? Yes
If you put your hands on both while its playing can you tell if they are in phase with eachother? Yes
What are the knob settings on the plate amp & what are the settings for it in your receiver?
Subwoofer=Crossover is all the way to the right (LFE input being used, so this should not matter). Output level is 10 o'clock, phase is @ 0.
Receiver = Level is 3.0, crossover is 120hz, LFE+main, placed about 8-10' from primary listening area and currently underneath TV / Front mains. ( I have also placed it in the rear of the room)