XPS 13 (9343) sound popping, esp. when streaming

Ever since upgrading to Windows 10, the sound on my XPS 13 pops, particularly when video is being streamed (i.e. Netflix, Youtube). I hear intermittent crackling sound that will temporarily stop (for max 1 minute) if the video is reloaded or paused and played again. This noise is not apparent when I plug in my headphones. All of my drivers are up to date. I've turned off enhancements, updated any video streaming software/plugins, and no change.

FYI, I'm having exactly the same problem on an Alienware M15x circa 2010.