Okay i see the problem. There is a general misconception to what the LFE cable/ out put does. By def it mean Low frequency effect channel that movie producers throw in- in music there is no such channel. So that means this channel is NOT what you want to use as the main signal source to your sub. So now this is how i reccomend you hook up the sub. Get a single cable that goes from the sub out of the receiver to the LFE. Then take an rca cable and connect it to the audio out of the receiver, just to the left of your sub out, and connect that to the line in of the woofer. Now on the receiver make sure its set to the mode to send signal to the sub. Now regardless of what you are playing you should be able to get the full kick out of your sub, and a little bit of extra sugar with the LFE when you specifically play movies.
any more questions?