ok so i have a FI Q 18" (fully loaded) off a cadence dakota 1200x1 rms amp. on certain songs and after played for a while, the sub will bottom out on certain songs. (i was told that weird noise was bottoming out) ive searched n searched but all the ones i found were discussing ports...i have a sealed 5 cu ft. box. so could it be that my amp is gettin hot and losing control of the sub? or what?