Hi Paul. You should have a menu in your AVR for 2ch direct/stereo where you can select the subwoofer. On my Denon 2809 it is under "Manual Setup"....then "Audio Setup"....then "2ch Direct/Stereo"....under "custom" you can set your fronts up how you like, and assign your subwoofer to use, the subwoofer mode and set the crossover and distance to the sub.

Half of communication is listening. You can't listen with your mouth.