subwoofer rattles like hell

hi rich, it is connected speaker level with paul speltz's anti cable, solid copper wire, nice cables. it is conected to a yamaha ca-1010 integrated amp. the gain i refer to is the knob for gain on the back of the sub. i can't turn the volume on the amp past three, way too loud beyond that. thanks.

Alrau1, it is a push pull configuration so i think if the drivers are pushed too hard it might overload just one of them. what you say does make sense though. problem being i bought it used and it seemed to work pretty good until i made all my adjustments and break in time of the other components, so manufacturers warranty is not an option. it, sadly, was a stretch for me to purchase even used (i'm saving for a bigger house) and i fear repairing will be out of the question. i guess i was hoping for a different answer but thanks a ton for everybodies input!

thanks for your attention, i had done all those things, i am contacting mirage.