simple over powering. 2x more then it can handle at a daily pace. burnt a coil. find a sub thats closer to that wattage easy as pie rlly. setting an amp is easy. there are "professional" ways of doing it. but u can do it by ear.

 

^^madwarrior says it best. i have no doubt in my mind that my amp (jbl 601.1 Class D Monoblock) is putting 480rms of CLEAN power out at 2ohm but my poor little pioneer sub that was engineered to bring a moderate amount of base to a small space was clearly not built to handle that much power, it even says best used with amps that put out less than 300w rms. i am thinking yes, the type r will handle more power but the same idea applys its meant to bring moderate amount of base to a small space, so with a 4 ohm sub it will be in a much, much happier power situation at 424w rms. Also i had no warning my coil was frying this time, blasting down the highway with all the windows down, and music cranked, i wonder how bad it would have smelled if the windows were closed lol, needless to say the inside of my box smells...interesting

alpine also supplies this little graph