I’ve been following the discussion about resetting to non-EU standards in an effort to increase player volume. That will certainly help – but there is another more effective way.
Just go to Music Settings and increase the gain setting of the Music Equalizer. Nominally the frequency bands are set to mid-level so that users can boost the bass and treble by selecting the various pre-programmed music-type settings. If you’d like to boost the overall volume, just go to Custom and boost the mid-frequencies as well.
I did this to boost the volume for audio books, but now I use this same setting for music as well. Works great for me. All the volume and sound quality I could possibly want!