When a sub is blown it usually makes a scratcy or grinding noise if you push the sub in but if its blow it realy wont make much of a sound so it sounds like your voice coil is going out you will want to get this looked at quick or it can get expensive...i had one were it was cheaper to buy a new sub rather than fix it. it can also just be it disorting from too much power. i would never go over the power limit when dealing with 3000 watts, that can get realy expensive quick