Your noise sounds (ugh, scuse the pun! *slaps forehead*) like Tinnitus, from what you've said. But don't worry about it - it's perfectly normal. It's only if you have other funny things going on (eg vertigo) that you might want to contemplate worrying about it.
A word of caution - if you focus on it, it might start bothering you.
Mine bothers me in exams and I was quite relieved to find that I didn't have to (as I'd always thought) 'put up with it because everyone else does' - I now have white noise generators (colloquially known as maskers lol) which help They distract me from the T, and they're rather sotthing anyway. Yay.
And. Most people with T have it for no apparent reason. I've had it since before I can remember, and I certainly wasn't exposed to loud noises at any stage of my life!
But yeah, don't focus on it too much and don't worry about it. Else you might find yourself being unable to ignore it.
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Spectrumite ... somewhere.