i have the same problem.....
my old unit (just a regualar panasonic cd player) had two rca sub preamp outputs. they were 4 volt. i recently bought a jensen dvd/cd player with a flip out screen. it only has one rca out for the subs. i had to use a splitter to plug in my rca's from my amp. the new one is only 2 volts. i am getting maybe half the bass i was before even after having to max out my amp. i am sorely dissapointed. i am returning the one i just bought and gonna trade it for a panasonic dvd/cd player with a flip out screen. i was told by one person the loss of bass was from going from panasonic to jensen. someone else said it was because of going from 4 to 2 volts on the preamps and having only one sub out rca. WHAT IS THE REASON for such a drastic loss in bass??? the new panasonic that im about to trade in for also has only one? do all the new decks have one and why? i dont wanna go through all the switching and installing and be left with the same result of minimal bass. i have 3 alpine type r's that used to bang my trunk off but now it barely moves. someone please help. thank you.