I had a 10" enclosed rockford sub installed, with a 200 watt rockford amp. I paid like $350 total, It was wayy too loud, wayy too much bass even with the bass all the way down. so I checked it out, they were drawing the signal from the left rear speaker, which someone here told me was bad and should be drawing the signal from before the stock amp, so I removed the liner and everything, found the right wires (thanks to silvernights posts!) and reconnect with no problems at all!
now it sounds great, not nearly as much bass, but it works with the system now. before, it was just doing its own thing. even with the volume on just one bar, there was still bass bumping. I also got my midrange back! I don't know shit about car stereos, so when I took off the covers for the amp, I didn't know there was bass boost setting and gain adjustment and crossover control. those guys never told me about that. even when I called and complained!
Now i'll have more confidence when messing with the stereo!
thanks guys!