I received my headset and it was fine for a few seconds and then this erratic popping/crackling sound began (random intervals between the pops). It is like listening to an old record.
It does the same thing when I plug audio buds into the 3.5 jack.
My wife can hear the sound from the couch so it is pretty distinctive.
I've also tested on 2 computers with the same result.
I just recieved my Rift S today and the audio coming from the headphones is crackling and popping non-stop. UPDATE: I was asked by support to return the unit for a replacement.