I tried the softvol trick in mplayer, but it did not seem to make a difference (between softvol=true and softvol=false). However, I installed ogg-support (0.7) before (instead of mogg), and it did seem to make a big difference in the volume!

Now the media playing is working decently (, so I'm thinking whether I'll get rid of OS2007HE to free up some space.