The RXA will have several settings for audio pass through, try pure direct mode when comparing the output from the center channel.
If its louder in pure direct mode its in the settings programmed in the avr. There should be a pure direct button on the front face of the avr and on the remote.
Have you tried removing and reinstalling or swapping your HDMI cable?

Last edited by brwsaw; 04/28/18 08:46 PM.