Have you verified that the amp is receiving the full 12-15V? And checked all the obvious settings on the amp? Low pass filter, gain, etc? I can't imagine why it would be different in the Cruze over a different vehicle with the same set-up, especially if you're using a line level-RCA converter. I wasn't able to compare mine with my last vehicle because I broke my amp out of frustration trying to take it back out of the Cobalt. So I bought a new one. One thing I will note, my Cobalt's stock sound system was much louder than my Cruze's.
Do your subs have dual voice coils? The only thing I can come up with is your impedance is higher now. If you've accidentally wired the sub coils in series then you would not be getting as much power through them as you should. You can check your impedance with a multi meter to be sure you're running 2 ohms or 4 ohms, whatever the lowest your amp can handle is.
There probably isn't any settings on the converter, check the amp though.
That isn't true, blown subs just sound really bad. The coils will still move, but they aren't connected to the cones so it'll sound really rattly. Since you have two DVCs theres no way to run a 2 ohm load, you can run either 1 ohm or 4 ohms. Most amps won't accept 1 ohm, so you'll have to wire them to get 4 ohms. Which will give you the same results as wiring one DVC for a 2 ohm load. I'd consider testing one sub at a time, in this configuration (given your amp is rated for 2 ohms) *Note: Also assuming your subs are 4 ohm subs.
Im actually in the same boat as the OP. You can't turn the bass up much at all on the head unit or else it distorts the door speakers like crazy.
