Mr Bateman is probably right about a null around 150hz and how to go about fixing it. Usually it's a cancellation problem when your EQ doesn't affect the dip in response. You can also vary the slope of the crossover to eliminate the null.

I think you also have cabin gain at ~300hz. Try taking ~250hz & 400hz down a few db. As another poster mentioned, this is a tough area in the response curve in car audio. The rest of the response curve looks pretty good.