MartinLogan was just trying to have options available for people.
If you have a receiver like yours, then you can have the receiver manage which frequencies go to the sub and which go to the other speakers. I think that's the best. When that's the case, you'd want to use the subwoofer output on the receiver and the LFE (low frequency effects) input on your sub.
If you don't have a subwoofer output on the receiver but instead have a set of left/right analog pre-amp outputs, then you could connect those to the left/right inputs on the sub. Then, you'd use the low pass filter control on the sub to manage which frequencies the sub would play.
Not all subs have inputs labeled "LFE." Some will say in the manual which input (if it matters) to plug the subwoofer output from a receiver into. Other subs have an LFE input that bypasses the sub's internal low pass filter (I don't think that yours does that). So, there are different options available out there.
In short - your receiver will handle figuring out which frequencies go where, so you're in good shape connecting to that LFE input. I would set the sub's low pass filter control to the highest possible number - that's to make it so that the sub doesn't filter out frequencies that you want it to play.
