I have an HK avr525, a Yamaha SW150 sub, and Polk Audio RM6500 speakers. I have recently wired my sub directly to the receiver rather than having the front speakers run in and out of it. I have noticed that my bass response is not as strong as before. On the 525, there are sub settings for Global, or Independent. Which should I use, also, what should I have the crossovers set for the fronts, center, surrounds and sub, to improve the sound quality? Thanks!!