I crossed my mains over at 40Hz, my center at 80Hz, and my surrounds at 80Hz. Is the mains signal above 40Hz sent to the mains and below 40Hz to the sub? Is the center signal above 80Hz sent to the center and below 80Hz to the sub? At what frequency is the LFE signal low passed, 40Hz or 80Hz?

With the crossover arrangement you describe, here's what would happen (assuming the crossovers to be absolute at the set frequency, although in reality they are a slope that operates around that frequency):

• Data below 40Hz from the left and right channels is redirected to the subwoofer.
• Data below 80Hz from the center and surrounds is redirected to the subwoofer.
• All "LFE" data (the ".1" channel in Dolby Digital 5.1 and DTS soundtracks) is sent directly to the subwoofer, where it merges with low frequency data redirected to the subwoofer from the other channels.

Does that help any?

Yes, thanx.

Assuming that your speakers in question are set to small.