2004 Impala, factory radio and amp, just installed 2 Infinity 692.7i in the rear. When I am sitting normally in drivers seat I can hardly hear any bass at all. If I lean forward toward the windshield the speakers sound amazing. They thump when you're sitting in the back seat too. But when I'm just sitting up front they lose literally all their boom. It really is crazy the difference from leaning forward and sitting back in the front. Obviously I want it to sound good where Im sitting all the time. Any ideas on how to fix this?