The SB-2's go down to 56Hz but I am not going to use them for now, maybe as surround backs in the future. The KSF 10.5's, I am going to use as fronts go down to 36Hz as do the KSF 8.5's that I am going too use as surround L&R so that is why I am unsure if I should set them as small or large.. I have turned the crossover on my sub all the way up and set the reciever crossover to 80Hz.