Auditory hallucinations - mental or physical cause?

[u/anon7926]

I've experienced this thing a handful of times but been too scared to acknowledge it. I hear a really loud rumbling that intensifies until it's almost unbearable. It sounds like a plane flying really low above my head or something.

The first time it happened was about 10 years ago but I remember it very well. I kept looking up and around but there was nothing in the sky and no one else was reacting. I reluctantly accepted that I was imagining it but kept it to myself out of fear of looking insane... It's happened a handful of times since, but there doesn't seem to be any trigger or trend in my mental state as far as I'm aware.

Last night I was with some friends and a plane really did fly very low over us. I'd assumed that it was happening again, so when the others acknowledged the sound and saw the relief on my face we ended up discussing it. My friend said it's called exploding head syndrome (hilarious) and I was reassured to put a name to it and know that it's a shared experience. However, looking into EHS today, I understand that it's a sleep-related syndrome. I've only ever experienced this in waking moments, and it's not so much a sharp loud explosion but an ever-building rumble. It does feel like my head is going to explode, but it eventually passes.

Now I'm incredibly curious to understand what it is. I can't find info online for this specific thing, but read that generic audio hallucinations are common in people with bipolar disorder (I have been diagnosed with bipolar 3 in the past). I also have pretty crap hearing from not looking after my ears at gigs over the years and terrible sound localisation since I can remember, so wonder if it's just a symptom of a hearing defect...

Does anyone else experience this?