Hello all, first time poster. I recently acquired a single Alpine SWR-12D4 powered with a MRX-M110.
The other day, with a DMM, I tuned the amps gain to be slightly under the max RMS of the sub. While playing, after maybe 10 minutes maximum the sub had some smoke coming from the ported box. The sub still plays though i question how well, it has always seemed to be quieter then anticipated. I've tested each voice coil with a DMM of which both are still reading the correct Ohm. In addition there is now some sort of rattle coming from the sub while playing and even when I removed it from the box and gave it a quick shake. Everything is under warranty still, basically I'm looking for the best diagnosis and the steps needed to have trouble free listening pleasure again.

Any information would be greatly appreciated.