What I'm talking about is not related to balancing the the speakers as you guys are talking about. I run the sub pretty lean. The changes I notice are more in the mids and highs and is somewhat hard to describe but I'll try: a little less reverberation, vocals are a little less "breathy", soundstaging is diminished.

The real test would be to turn the cross-over on the H/K to its lowest setting and then turn the sub off. I could A/B between no sub/no crossover and no sub with crossover engaged. Haven't had time to play like that lately.