Try switching ears & see if problem move to other ear or not. If problem sound moves it is your earphones. If not have your ears checked. I had a crackling in my right ear & the crackling sound did not move with suspected driver but stayed with my right ear. Some months later I had sudden hearing loss in my right ear. Then distortion got really bad on that side after hearing loss. I still have hearing loss in that ear but much of the distortion has left. Most sound above 5KHz is severely reduced & gone by 9KHz altogether on that ear. I did recover some hearing in that ear as right after hearing loss I had nothing above 2KHz. Before hearing loss I could hear up to 15 KHz.