You need to connect the subwoofer signal through the SMS-1 and then connect the SMS-1's EQ output (both audio and video) to an input on your receiver (the SMS-1 guide I linked to in my previous post can help a lot in explaining what's going on). The SMS-1's test sweeps will run from 15Hz or so up to 200Hz, which will involve both your sub and your mains. This is done in part to help work out the integration of the sub with the mains (adjusting the phase and the volume levels, for example). It also allows the test sweep to work with a wide assortment of crossover points between sub and mains, since not everybody crosses over at 80Hz.