Please help. I bought a jvc 50x4 stereo with 22rms and installed 4 jvc 230w with 40w rms speakers which are 6.5 inch and are installed in the doors where the old ones came out. At a certain level the speakers get distorted, and the bass does not sound very good. Have double checked wiring and made sure speakers are mounted tightly but still sound poor. Have had jvc before and should sound better than the factory ones. What could be the problem