**Exploding head syndrome is a parasomnia condition that causes the sufferer occasionally to experience a tremendously loud noise as originating from within his or her own head, usually described as the sound of an explosion, roar, gunshot, loud voices or screams, a ringing noise, or the sound of electrical arcing (buzzing). Exploding head syndrome - Wikipedia, the free encyclopedia
I've often been aware of the moment that the ear transitions from hearing the outside physical world and shuts down so that you only hear the "inner" workings of the body, such as very loud heartbeat. I used to think that this transition to hearing the heartbeat was the sole cause of the exploding head syndrome**...or the violently loud throbbing noise you might experience during SP. But now I'm aware that this transition is even more affected by any noises in your bedroom. For example, a fan, music, or television, will change from normal sound...when the ear makes that transition to shutting off the outside world...and will turn into extremely loud static. It's as though someone changed the channel to snow and turned the volume all the way up. I'm pretty good at turning violent and frightening SP noises and physical sensations into more pleasant things, but even for me, at times the exploding head noise is too loud and invasive to allow me to fall asleep or enter a LD.

So because I sleep with my fan on pretty loudly, I experience this quite a bit. But I can't sleep without my fan on. If you do sleep in dead silence, then you might never have this problem. But quite simply, blocking the noise by covering your ear with a blanket or sheet 100% effectively stops the violent noise. I sleep on my side so one ear is already buried in the pillow, so I just threw my blanket over the uncovered ear, and it worked at stopping any unpleasant sound.

I've tested it several times, with different noises, including the tv, and it works every time at stopping the violent noises of SP. So I realize it's an oddly specific situation, but if you find yourself plagued by exploding head syndrome/violent noises during SP, just cover your ears. Or hell, get some soft and comfy earplugs if your situation is bad enough.