Sound trouble through Amplifier Yamaha RXV675

[apollo13]

Hello

I encounter a trouble audio while using VLC with my MacBook Pro:
I connect the Macbook with HDMI to my Video Ampli Yamha RXV675 through the "video Aux Hdmi", connected to my tv.
When I am reading HD video with VLC, the video is perfect, but the sound is horrible in the Ampli
I tried many audio parameters with VLC and the amplier, but nothing change, particularly when the sound is actions.

do someone has an idea on that topic?