To compensate for individual tastes, the iPod's EQ setting can be adjusted by each user. Go to Settings > EQ in the iPod menu. However, if there's one or more songs that lack high end or maybe sound boomy, then you have to adjust these tracks in iTunes. Choose the track(s) you want to tweak, then hit Command + I (capital letter "i" not the digit 1). At the top you click on Options where you can then choose one of the Equalizer presets. This is also where you'll want to go when you find a particular song that's louder than all the others.