2002 tl type s
When I start my car and my radio is off bass comes through my sub really loud and then i turn the radio on everything is good

Also if my sub is not thumping could it be blown it rattles but it does not quake in and out Im thinking its the sub or maybe the box the sub is in is too small?

I have a 1200 watts kenwood 12 sub hooked up to a mtx mono 620 or 820D any input is appreciated

 

take out the sub and check the coils with a dmm

 

Do you have a stock headunit?

 

did the problem just start? Was it working and then stop?