Have you noticed your new CDs are louder than your old CDs (or even albums)? That's because the volume has been turned up in the mastering process. This results in a loss of dynamics (less difference between quiet and loud) and hence a worse sounding record. Now there's an industry organisation called Turn Me Up campaigning for a return to dynamics. They've made a demo video (embedded below from YouTube) which demonstrates the effects. Music Machinery has an excellent entry (complete with graphs) on this subject and here's the Wikipedia article. Quiet is the new loud.