I noticied that one of my speaker cabs was not working, so I pulled the speaker out and one of the wires to the terminals had come off. I was pretty proud of myself. I reattached it to ensure it wouldn't pop off again, put the speaker back in and fired it up. The speaker now had a rattle coming from the voice coil and I thought for sure the speaker was gone. I pulled the speaker out again, hoping it would be covered under warranty and as I was starting to get it ready for packaging, I noticed a staple (probably from the insulation batting inside the cabinet) had attached itself to the inside of the magnet and was touching the paper speaker cone. I removed it, thinking it was unlikely it was the culprit, but sure enough that's all it was. Amazing how a little staple could make so much noise. I slept a lot better last night.