My car sounds so good with the Deck installed you can hear the quality and bass from the speakers but once i put the rca wires and subs and amp hooked up it doesnt sound teh same from teh speakers does it mean the volts are being taken away from teh speaker outputs to the Sub/Amp combo?
you could try some baffles or some type of sound deadener to keep the bass waves away from the speakers and get more sound out of them. but brandon is probably right.