What does the display on your receiver show (what is it set to) when you are watching movies? If your using multi-channel analog, it will have its own separate input.
Another thing is when you are adjusting the trim levels on the center (does it actually get louder)? If not then it it bypassed.
Do you have any other audio cables connected to your blu-ray player?
If the receiver is doing the processing turn off dynamic range control.
BTW since your blu-ray player has multi-channel analog out connections it will have its own bass management and setup in the player itself which you have not mentioned.
