what was ur crossover at? did u set ur gain with it at that?, that will blow some of the subs frequency range. somethin that happened when i had my cheap LA 12" sub. i had lpf at 50 hz set gain with 50 hz -6 db tone, sub hit good then didn't hit as good as days went by, like it got weaker and weaker, everything up from 60 hz it still played.