Loud noise can do two things to the ears. It can deafen, or it can lead to over-sensitive ears.

Inside the cochlea (shell) there are tiny, hairlike nerve endings. Truly loud noise can break them right off, and the "root" where they were attached becomes sensitive to future loud noise. High-pitched nerve endings are especially vulnerable. I have that problem.

Another problem that can follow is ringing in the ears. There's a theory that the ringing is caused by the brain, which is trying to re-create the input it should be getting from those lost nerves.

I learned this from an article in a magazine by an audiologist and from two hearing M.D.'s (whatever you call that specialty.) At one point a hearing test caused me such pain that I screamed "No! No!" and leapt out of my chair. The damn assistant didn't offer even a flicker of apology. She was like a robot, hurting me.

Almost all the blasts of sound which have hurt me were preventable. The sign should say, "IF the music is too loud, you have been victimized by fools."