So today my friend showed me his 2 12" MTx terminators that i sold him (brand new). They are in a sealed box with a kenwood amp i (forget what kind). He got it all installed MAYBE a week ago. I told him they need to break in so he kept them low, and has been very happy with them. They were working perfectly up until today. Before we went to lunch they worked fine, but a few hours later when we came back he turned them on and a terrible noise was coming out of them. It sounded like the cone has seperated from the basket (if even possible)... When i pushed on the subs they were still stiff. But when i pushed it would reach a point then basically make a pop feeling if that makes sense. I did this to BOTH subs and they did the same. I could here the air pushed out in the box but they felt weird when i pushed on them. We turned off the car and disconnected them. Then reconnected and turned the car back on, no change. They are in a sealed box and we didnt take them out to check. But if anyone can help me out and tell me what you think it is? I would greatly appreciate it. Thanks