I had this sub installed in my car for years and worked great. Had to take it out and it sat in storage for a while and rats had gone in the enclosure and chewed through the foam layering covering the back of the driver (pictures attached) is this foam covering necessary for the sub to work correctly or is it just an extra layer of security so nothing hits the back of the driver. All of the other components (wiring,etc) look new. Is this sub destroyed? Sorry as I am not very educated on the workings of subwoofers and this might be an obvious answer.