Between the OP's question and my response, you should be able to get a pretty good idea about what you're asking. Remember, OP's front speakers are his
only speakers.
http://forums.audioholics.com/forums/showthread.php?t=32506
Who ever suggested running a sub off of their front speakers of a HT system? If you've got a LFE or sub out and a powered sub, there's no reason to. Now, that shoulfd give you a big clue.