I recently installed one 10" subwoofer into my standard cab 1999 Chevy S10. I purchased a Sony 1200w Sub with a slim truck series box, since I have very little room behind my seats. I bought a sony MP3 Deck as well. I installed an older model Rockford fosgate 500w amp that Ive had for about 10 years and used in several different cars. This is the first time I've used it to power a 10" as I've always used a larger 12" woofer. Install was clean and everything worked fine, however, after about 30 mins of use, the woofer starts to rattle very loudly, putting your finger on the cone stops the rattle, so I know its coming from the cone area and its not something in the truck. The sub is very warm to the touch. If you turn the system off and wait about 10 minutes the rattle/distortion is gone and starts to rattle after a few minutes of use. At first I thought I blew the sub but it seems to fix itself after cooling down. What can I do to solve this? Do I need a higher power sub? Thanks in advance.