I just tried toggling the settings > volume between ‘normal’ and ‘high’ – it didn’t seem to do anything at all – what does that do for you?
It ‘lengthens’ the volume bar. So, if you’re at max volume when on normal, switch to high, then the volume bar should now only register at about 66%.
This is on an ‘American’ firmware player (although apparently you can switch between firmwares). Not sure if European players ignore this option (Region listed in version.sdk).
Listening to the music and radio is about the same volume, and loud enough to drown out the TV (although not too loud), that’s on maximum normal volume - max high hurts.