I have some Kenwood KS-H52 Speakers I picked up for 25 bucks and got a 7.1 1000 watt receiver that came with a subwoofer. before I picked up the receiver I have a older Panasonic unit that was built to drive 6.5 inch speaker and the bass sounded amazing for how old they are, after hooking up the receiver the sub sounds great but the built in subwoofers are not working, How can I make the subwoofer work as well as the built in ones? The Panasonic unit was a small 2 channel stereo., Thanks