So i have 2 DVC 12" XE competition MA audio subwoofers in a ported box with about 1.6 cubic feet per chamber hooked up to a boss bl100 2 channel amp and a sony xlpod head unit(best one they had at best buy). Im not sure if my subs are blown or if my amp has gone bad. when i evenly push the cones in there is no scathing sound nor is there a change in resistance from when brand new. the subs sound very well for the most part they just make some what of a humming noise when hitting lower notes. I have them hooked up like this http://akamaipix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/2DVC_4-ohm_2ch.jpg Please help i am not sure what is wrong.