Woofer cracking

JoeA4

I have two 10" momo woofers. I hooked one up in a new fiberglass enclosure I made and it had a cracking sound when I turned the volume up. The amplifier's gain and bass boost are set to the mid of their low and high setting ranges. When I had them in the old enclusures, the amplifiers settings were set almost to their max and the woofers were crystal clear. I've had them stored in my room with a towl laying over them for a year. The room is always at room temp with air conditioning, so I don't think they were stored incorrectly. I attmepted to hook the one speaker up into the old enclosure again and it gave me the cracking sound. I filled the box with polyester fiber fill like I've know some people to to with their enclosures and i got the same results. Upon inspection of the one woofer I did not hook up, I noticed a small tear inthe ribbed diaphragm under the cone of the speaker. The tear is right around where the cone is bonded to the diaphragm. What is the most common reason for this damage and how do I fix it. The I do believe I only had a year warranty on them and that has expired. Any advice/suggestions are greatly appreciated!