So I bought this 91 a little bit ago. Love the car immeasurably but like us all I keep finding little things that aren't right. Right now I can't figure out what is going on with that big speaker dead center of rear. I am assuming it is a woofer but it does not thump as such. I put in a heavy bass CD and send sound to rear only and the door speakers are the only ones producing sound. Everything else sounds clear as a bell (no Nakamichi unfortunatly). Any help would be greatly appreciated.

I also have a 91 LS 400 there is a small amp in the trunk that drives the sub woofer speaker it is only 2 ohms I had the speaker taken out and put in a regular subwoofer and put in a 200 amp to drive it. you will play hell trying to find a 2 ohm amp to drive the back deck speaker. I had Fry's techs put in the speaker and amp and it really get the base moving. All the speakers in the 91 LS 400 are 2 ohm I left the rest alone the front stereo unit drives the front and back door speakers I am coming up on 322,000 miles and everything is original including the A/C they build great cars.