David, so that's the way that Pioneer unit accomplishes bass management. The High Pass Filter rolls off the speakers below the selected frequency and the "cut off frequency" rolls off the sub above the selected frequency. Consistent with home audio practice, both should be set to the same frequency for the smoothest blend(unless you want the overlap that you mention for "double bass" to some extent). From the frequency response shown for the speakers, 80Hz should work well as the crossover.


Enjoy the music, not the equipment.