I have 2 15" MTX thunder 4500's running at 4 ohms off a memphis 1000 watt d class. I was riding around town today when I noticed a remarkable difference in output.. I checked the subs when I got home, to see that one had NO output at all.. I took the sub out to look at it, and the voice coil seems to be "seperated" or torn away from the spider.. Is this the reason that the sub stopped working, and is it repairable? It's not a major concern, I only had these subs as a temporary fix until I order my 15" Fi BL. It would still be nice to have both of these subs in working order though. Any thoughts?

here's a link to a video of what happened..

http://www.youtube.com/watch?v=OwHBUcLlb-c

I think you aleady answered your own question.

I think you aleady answered your own question.

Well I mean it's pretty obvious, but is it repairable? And what are the possible reasons that it happened

It's not worth repairing.

That sub failed due to mechanical failure, be careful in the future when your running that BL, as it is a very high quality woofer but it can break just like the MTX did.

agreed, cone broke from the spider. your sub unloaded. Call mtx and get a recone ( if its worth it to you)

Too much excursion.

Too much excursion.

It looks like the only thing that happened was the glue came loose.. Is it possible to just glue it back together? Or is there a more detailed reason to why this caused it stop working?

You may be able to glue it back together. I forget what kind they use on there, CA glue or something?

It broke because the spider can only stretch so far. It's like taping one end of a rubber band to a desk and then pulling on the other end. The spider is attached to the basket, like the rubber band to the desk. When you pull the rubber band up (ie- the cone moves out during excursion) it can stretch to a point, then at some point the tape will give away from the desk and you will pull it off (ie- the spider will either rip or the glue will come undone from the former).

You may want to take a DMM and measure the resistance of the coils, though, also. Usually when you have mechanical damage like this the voice coil will still move up and down in the motor so the sub will still technically work and it might make some bad noises as it scratches around without support from the spider. But you could have also either burned the voice coils, which then the heat may have melted the glue on the spider joint, or you could have also snapped the tinsel leads during the overexcursion, which won't allow any power to the voice coils.

I know you can secure a surround with a two part epoxy. I'm not sure about the spider though.

They use CA glue or epoxy (depending on company) on the triple joint.

I'm willing to bet the coil destroyed itself then it came out of the gap and hit the top plate, can you look at it through the vents? Measure resistance as well.