everything got "muddy"

Just wanted to note something unexpected that I experienced today. Last week I hooked up a pair of RTi70's to my receiver and loved the sound I got even better than the sound room at the store....bi-wired 'em and got an improvement in the highs and the midrange seemed "warmer"...and amazingly to me, these things can actually hold their bass well too! Anyway, I also ordered the PSW350 to compliment the bass duties thinking I would have a nice set-up. Sub was hooked with Monster sub cable to the LFE input......sounded muddy. Unhooked that and tried both the left and right side of the L/R rca inputs.....still sounds muddy. (Better, but still muddy) Obviously, I am thinking of hooking up the line level inputs to the sub next, but I really don't want to miss out on the bi-wire enhancement. And I would like to keep the speaker cable mess down to a minimum.LOL (is that ever acheivable?) The receiver is a JVC RX-992, with a built-in eq.....(a feature that I really don't like, but have learned to deal with) the manual says nothing about hooking up a sub except that if the consumer wishes to hook a sub to the product to buy a seprately puchased sub and hook it up via rca cable....nothing on filtered or unfiltered and there is no way to program a setting of main or small or anything, just a "subwoofer out" jack on the back. After playing various CD's (Van Halen's Balance, Sammy Hagar's UnBoxed, AC/DC's FTATR, etc) the best I could come up with was the sub at a 90 degree angle in the corner behind the left speaker with the mains about 10 feet apart. The sub hooked at the left rca input, not the LFE input....the cross set at the max and the volume at about half to 3/4 . Is there any one that can let me know if there is something that I am missing in getting a "cleaner" sound out of my rig? I am almost considering sending the sub back and just being happy with the RTi70's as a stand alone rig. But then again are we really ever just "happy" with anything? Thanks for the posts.