Eliminating sound problems (crackling, popping, stuttering) on a Dell Vostro 1700

I really like the Vostro 1700, but one of the few problematic areas is the sound system. When the computer is completely idle -- no programs running, no downloading, no nothing -- the sound playback from MP3's, WAV's, even CD's has lots of crackling and popping in it. The problem is pretty noticeable since the audio interruptions occur once or twice a minute.

After some web searching, I found that some people have cured similar sound problems on other Dell notebooks by disabling the 802.11a band of the wireless network card. This band is not used for b or g communication, and so probably will not affect wireless communication with modern routers. I disabled the a band (control panel -> system -> device manager -> network card -> options) and it seems to have cured the sound problems completely. I'm guessing the 802.11a frequency domain interfered with the Sigmatel audio chip. Lousy RFI/EMI protection?