I recentley bought a new cd player and sub. The cd player is pioneer 7800-mp with 5 volt preouts. The subwoofer is a JL Audio 12W6v2-D4 in a JL powerwedge box powered by an Alpine MRD-M500 mono block amp rated at 500rms. The sound is horrible. Basically the old CD player (pioneer 7600) and sub (JL 12W3v2-D-4) sounded a lot better. Am i missing something. I have to turn the gain half way down on the amp to even get a decent sound out of the sub otherwise the sub sounds distorted. I am running the amp and sub at 2 ohms. Any ideas?