You can set your mains to a lower crossover point as well and still have them set to small, with most of the newer avr's out there. I have my M80s at 40 or 60 and set to small, this will direct anything at 40 hz and lower to the sub and leave the M80s to do the rest making full use of the ~35hz rating of the M80s and then some days I will try the LFE + Mains setting just for fun, sometimes I think it sounds better.
Randy do you remember why THX chose 80hz as the crossover point? No looking it up either.
