I have not messed with this stuff in a long time, but if your head unit has a bass level like you say, turn that down and adjust your sound with the knob on the amp driving the Sub first, sometimes you have to get that right then barely turn up the bass on your head unit so it sounds deep and clear, a good balance of bass and crisp sound will sound better.
Did you check to see the wires to the subs were not hooked up to negative polarity, are the subs pushing out when they hit ???
Also what ohm are the amps rated, how did you hook them up ?
Did you check to see the wires to the subs were not hooked up to negative polarity, are the subs pushing out when they hit ???
Also what ohm are the amps rated, how did you hook them up ?