Problem with xbox 360 and surround sound

[BttleFedC10]

Alrighty, the problem is that when its hooked up and playing a game or movie it doesnt like to play the more quiet stuff. When stuff gets loud it, you can hear it clear as day. You can put your ear up to the speaker and can hear not playing some of the more quieter sounds. The surround system is an RCA. Any way to fix it?

Also whenever i try to plug up the optical port for the sound, I just get a loud annoying beep. Therefore I just use the normal.