blown sub?

sup fellas,
my sister has 2 mtx subs which i believe are the thunder4500 and some sort of hifonics amp i donno, but they have been sounding kind of weird latelly. i dont kow if they are blown since ive never heard a blown sub before but by searching it sounds as if it should sound like popping. anyway they have been running perfect for the past couple of years and now when the music plays the right sub makes a sound like...i donno how to explain it..probably something like if a piece of paper is vibrating really fast. sorry for the lack of info but it is kind of hard to explain. if anyone has any feedback it would be greatly appreciated. thanks

if it sounds like a peice of paper shaking really fast and kinda loud. probably a fried voice coil. it stinks too. not repairable, buy some new ones

http://cgi.ebay.com/MTX-12-thunder-4500-450w-max-225w-rms-DVC_W0QQitemZ5835776909QQcategoryZ39778QQssPageNam eZWDVWQQrdZ1QQcmdZViewItem

yea i thought it was dead lol. btw is there anyway i can tell if it is for sure by looking at it? what could have caused this?

short of taking the sub apart itll be hard to tell if its a voice coil. the 4500 is a dual voice coil sub. try hooking up one voice coil at a time. if it works with one but not with the other. there is your problem. if neither works it could be both coils but could also be few other things. sounds like a VC to me.

bust out the ohm meter, meter both coils.

if it is dual 4ohm coils each coil should be around 3.2ohm DC (check its t/s params to be sure).

If either coil is really high (like undreadable in the lowest ohm setting) you either melted the coil to where there is a break in the path or burnt the coil so the copper has uber high resistance. if it is really low you melted the casing on the wires of the coil.
Either way the driver is garbage.

However if it something like a loose tensile lead that is about to break off it can be soldered back on and oyur good to go.

alright then im checkin tomorrow.