I just encountered a similar experience. Crossing over my sub at 80Hz (used to be 35Hz) with sub built-in room correction. Very amazed it smoothly integrates with my floorstanders. Also in a relatively large room.
Sub best at high crossover?
I am wondering, is my ears deceiving me, or is the Velodyne DD-18 actually sounding better, when I defeat the crossover (by setting it to max, 199hz), and turn the volume some steps down? This is in a fairly large room, with the sub well positioned, augmenting full range speakers. I hope others will share experience.