i have 2 infinity reference 6x9's hooked up to a 40x4 sony 4 channel amp, they are loud as hell but have no bass but if i turn up the bass on my cd player it distorts like crazy, the only way they sound good is if i put the balance either all the way to the right or all the way to the left. but in the middle, no bass. What should i do to fix this problem, ive tried alot of stuff already.