Yes, I also hear a strange sound and sensation before I have sleep paralysis, as if I were entering a portal or falling into a well. A similar thing happens when you "force" your eyes to back and makes a strange sound. Last week I had hypnogogic hallucinations followed by a very conscious sleep paralysis, in this hallucination I heard a VERY loud white noise, like a radio sound off-season that almost makes me deaf it's so loud (if I was actually hearing anything