It's like a car idling outside. I put ear plugs in, but there it is, IN my head. Occasionally when it's loud, i feel soft buzzy vibrations in my legs.
Started about 9 months ago. And ive moved, but there it is. And if i don't hear it, i just need to think of it, and there it is, like im "calling on" it. Mainly my left ear but resonates throughout. Oh btw, im in Australia.