If the response curve messes up with the crossover at 60Hz, you may want to go back to using 80Hz - it's possible that there needs to be some room correction between 60Hz and 80Hz. This is exactly what happened to me - I had a peak at 63Hz, and the only way to quash it was to let the sub handle that range so the SMS-1 could take care of it (even though my Paradigms can comfortably get down into the 40's).