I started having these crackling sounds 3 days ago and it was frustrating because it was impossible for me to listen to my my music with tons of distortion or watching stuff. I searched endlessly on the net but found no fix, tried dcpchecker, latencymon, and driver updates, reinstall, ethernet, realtek blah blah blah but nothing worked, then I thought it could be a ground problem within my pc. so what I did was clean up my pc.
I opened my pc and it was full of dust. dust everywhere. spiders even mosquitoes living in my pc. freaking insects. first thing I did was disassemble my whole pc, cleaned out the dust from the motherboard, powersupply,videocard,ram and case anything were the PCB is physically EXPOSED. reassemble the pc then turn it on. second I opened my music player [media monkey] played some music at the same time doing the browser srcolling, window change anything that could throttle my cpu but no crackling had been encountered, now everything works fine. Im guessing there was some electrical dust ground looping something.