i have a 15 cerwin stroker, which i bought off ebaym and the cone was separating from second spider( i think) and it made that noise when it hit hard. I am still using it in my winter beater, the sq is crap, but you can actually hear it from over a mile away

97 V6 ATX 20,000 Miles alpine cda 9811 Alpine MRV-F357 hifonics brutus BX2000D 2 Kicker L7 15 I NEED GREY LEATHER DOOR PANELS!!!!!! Flip out monitor PS2 Spr-175a SPR-69LP SPR-57LS 60 Ft EDEAD