My sub in my MTX Thunderform is a 10" MTX 6000. I've had it about 4 years or so. Well, now it is fading in and out. I also feel that maybe it has lost power in some way since I have to turn the bass up very high to hear it anymore. The sub makes no sound until i press down on the center of the cone then it bumps as it should. I popped it open and I didnt see anything loose connection-wise so could something be wrong with the magnet? Any help appreciated, I cant stand being without it much longer!

 

if you get sound when pushing down on the cone then the sub is bad.