Use a Y-splitter from the Onkyo, and set the subs up so that they are both the same distance from the listening area. The Audyssey MultEQ XT setup tool will then measure and tune them as one.
Make sure you do all 8 measurements with Audyssey.
Set the subwoofer crossovers as high as you can.
Dave
Make sure you do all 8 measurements with Audyssey.
Set the subwoofer crossovers as high as you can.
Dave