A discussion I found around the Dell community about a crackling sound on a specific Dell XPS computer. Though, I didn’t personally experienced this (that’s because I can’t afford a Dell XPS, hehehehe) this might help you guys ever you’re encountering the same issue.
The audio corruption may occur if the Dell XPS 730 computer have a Creative Labs X-Fi card installed in it. Apparently, the users complaint of crackling sounds that come out of their computers when they move their mice.
The work-around so far is by downloading and installing this: XPS 730-010004 BIOS Update. It’s the version 1.0.4 of the Dell XPS 730 machine. You can check further info on this in Dell’s Community Forum website or Dell’s Support website.
Hope this helps!