I have perfect hearing and no head trauma.

I always though that Tinnitus was a high pitched ringing sound but the audiologist explained that tinnitus sounds are very varied.

The noise I experience is like the low whirring of a central heating system always on in the background sometimes with a regular beating sound very like the low bass in a song.

Over time I noticed that it was the clenching of my jaw, especially when under stress or worrying about stuff, that was the main cause of the sounds.

Laying in bed at night I can now stop the noises by relaxing my jaw with my mouth open while I am trying to fall to sleep.