Headunit/EQ issue

I have an Alpine head unit with a built in eq/crossover . I set the eq on the headunit to flat . I wanna use a Rockford Fosgate symmetry epx2 for the preamp crossover and eq instead of the headunit since I can load different eq settings and at the push of a button I can switch setting depending on what type of music I listen to . Also I can set the boost to minimum at 45 hz if I don’t want so much bass instead of adjusting the eq settings all the time on head unit .

Wondering if using the symmetry with the head unit I have is causing the issue with low output out of the symmetry or there is an issue with the symmetry itself .
Any thoughts ?