What you need:
- USB Keyboard and Mouse
Open the menu on the player (see http://support.aerissolutions.com.au/support/solutions/articles/4000123308-getting-to-the-menu-mbr1100-xmp2200-xmp6200)
Click on the advanced menu button
Click on the Display/sound (1) and then click Sound (2)
Click Sound (1), then adjust the volume bar (2).
Once you have got the volume set to the desired level, press OK (3).