I love Spotify, but recently I have been plagued by poor sound quality. Specifically I experienced clipping, popping and variations in volume level during playback. As far as I could tell this affected all the songs I played in Spotify. At first I thought the problem was specific to Spotify, but after doing some tests with Grooveshark and Windows Media Player I discovered that the problem affected all apps playing sound. After a little digging I discovered a workaround for the problem.
Open the Sound properties:
Select Properties for the Default Device, the select the Enhancements tab:
Select Disable all enhancements. If you are playing music it will momentarily pause and then continue, hopefully (as it did for me) with now crystal clear quality.
Last.FM profile: www.last.fm/user/morgands