That’s an astonishingly loud machine - I can barely hear mine. I sometimes lay and try to listen to it, but quickly I find the sound of my breathing makes up the majority of noise in the room.
It is not the machine at all. I have a ResMed AirSense 10 AutoSet. Bystanders tell me that they hear next to nothing. It is the sound that is made in the mask (ResMed AirFit F30i) when I inhale that drives me crazy. Every time I breathe in, it sounds like Darth Vader.
If sounds on your face and in your head are that noticeably loud, you may have obstructions in your ear canal, such as impacted earwax. Does your humming sound louder when you plug your ears, or does it stay the same?
I figured, since hearing protection solves the problem, it's not a problem inside the head. Well it might be after all as I am apparently super sound sensitive.
