I tried having the setting wherein the crossover was set to 100 or 80 with small for speakers. You hardly notice a difference in movies but with music I noticed with my speakers the soundstage was not as prominent. When I set it the speakers back to large the soundstage was back to its nice depth. With my setup I actually like having my cross over off at the reciever level and have the full frequencies sent to my sub. I had my subs crossover set to about 60hz and my speakers all set to large. That gave me the sound I enjoyed the most with my speakers.
I tried with many setting to the crossover on my reciever and the sub crossover set all to max to get it out of the way but it still sounded best with the sub setting the crossover and the speakers set to large.
Experiment and see what you enjoy the most with both movies and also music.

http://www.quadloft.com/hometheater- new HT