I tried to use the "volume adjuzt" slider. That will actually not adjust the max volume of MP3s. It will simply change how the volume increases. If you move the slider all the way to the right, what will happen while listening to the iPod is that you will reach the max volume at 50% of the volume bar on the iPod itself. If on your iPod you keep "increasing" the volume beyond 50% on the volume bar, you will get no result, as you are already at max. I do not understand what the purpose of such feature would be, but that's exactly how it works.