You asked where I set my subwoofer crossover.
I set my crossover point around 80 hz and the phase at 0 degree, then adjusted the output level on my sub until it sounded balanced with my main speakers. Seems to me I set the output level control around the 9:00 position, but your subwoofer setting may be different. Since my particular subwoofer has a roll off rate of 24 db/octive, this setting seems to work best with my N3S. Since not all listening rooms and placement are the same you will need to experiment with the settings until it sounds best to you. The settings I suggested will at least get you in the ball park.