I'm having the same problem on my machine, with an SB Live! using the
newpcm driver. I built world on 29 July. (My previous buildworld from
2 weeks ago had no problems)...
as a note... it seems that the clicking/crackling somehow relates to the
intensity of the sound... i notice the effect more with some of my louder
mp3's, and less with others (like classical pieces which can have brief
periods of silence)