I am not quite sure I understand your post. Are you saying you have your EP500 gain contol set to max while the gain on the receiver for the subwoofer is set -10?

Are you using an auto setup or an SPL meter when you calibrated?

I would set the subwoofer gain to the half point (maybe even less) and set the receiver trim to -4 to start and then gradually increase the trim on the receiver to level match the subwoofer using an SPL meter.

If using an auto setup, I would set the sub gain to half and run it mulitple times to see what kind of results you get.

I’m armed and I’m drinking. You don’t want to listen to advice from me, amigo.

-Max Payne