I remember sometimes waking up in the middle of the night and start noticing/hearing a loud as fuck deep humming sound that seems to have some kind of hearthbeat if I just stand laying on bed doing nothing, I have lived in totally different places and I remember hearing the exactly same sound sometimes at night I just seem to notice that happens the same day I would go hiking to certain place, everytime I notice the sound at night it feels like the sound is leaking itself through the walls and reverbs like being inside something like a water pipe
where I live now I think I hear it everytime I go into my dorm room that is very small sometimes it seems to sound way louder than other times and the sound seems to be easily drowned by other outside enviromental noises I have more experiences hearing that kind of sound but cant remember right now exact details