I have a 2009 Crew Cab with the Alpine system. I recently installed two 12'' subs and an amp, using the stock sub speaker wires for the amp. After enjoying my subs for a few days, I turned them down and noticed that my factory speakers sounded absolutely terrible. They no longer have any bass at all, and they sound very tinny and cheap. Adjusting bass/midrange/treble on the head unit does not change anything anymore. About the same time, I noticed an unpleasant burning/hot smell coming out of my vents. I have no idea what's happening, anybody have any suggestions, or any way to test the stock amp or head unit?