Polk Hampden desktop left speaker turns off

When I play droning/ambient music, my left Polk Hampden desktop speaker partially turns off after a few minutes (first I hear a "pop" sound, then the sound is cut and you can still hear a faint, muffled sound coming from it). It doesn't happen with other genres of music, and it's only the left speaker that has this issue.

Is there any possible fix to this problem?