I have this weird muscle in my ears I can flex to block out (or at least lessen) loud noises. I've never been able to explain it adequately to anyone, or find out what is going on, but it's absolutely real and not just, wait for it, .. in my head :-)
In modern cars when the vehicle detects an impending collision it floods the cabin with pink noise to trigger a reflexive contraction of this muscle to protect the passenger's hearing from the even louder sounds of the collision and the airbags.
I can do the rumbling too. And a clicking too. I can even make someone else hear my ear clicking by having them press their ear to mine. I wonder if that's causes by the same thing.
Same here, I hear a rumbling. I do occasionally use this to block or lower very loud (potentially hearing-damaging) sounds if there are no other means available.
