Boris Mikhaylov wrote a nice DSP effect some time ago called BS2B , or Bauer stereophonic-to-binaural for long. This effect applies a few tricks to make music better when listening through headphones. More (and quite interesting) details about the algorithm can be found on the official BS2B page. Boris wrote plugins for Winamp, Foobar 2000 0.8.x/0.9.x and the professional audio interface VST. I added an XMMS 1.x plugin to that list now. You can download it from SourceForge.