As sound output I am going to use a USB-3.5 minijack converter connected to the Raspberry Pi3. The mini Jack installed on the unit itself causes a lot of interference. I have followed the tutorial in this video to configure the USB output before that of the card itself.

Retropie user: Pi

Psw: Raspberry 

Commands: view the video

Remember reboot the pi3 after the save the file

I used to the test this product 

Usb-mini jack 3.5 female