ok....i have an alpine hu..speakers pump normally...rattles the car!..now..is there a way where i can use the hu to power the speakers normally?and use the stock amp to power a 400wtt. 12 sub???? ive tryed everything..ill even delete the back subs so the 12 will have more power...i want the hu to power the door and the stock amp to power the 12 sub...help???? thank you!