Does anyone have a link to a page that has information on diagnosing and repairing woofer problems? I've got a 15" subwoofer driver that I am getting very little output of (but the cone is moving somewhat with a signal I believe), Three other identical drivers work fine in the same configuration. I'm guessing its some sort of voice coil problem (are these symptoms characteristic of a frozen coil?) but I don't have too much experience in this arena.