well, I used to have super hearing. Had a hard time being around CRT displays because the flyback transformers were really really loud. Now, with age, I get a phantom limb tone of 16KHz. [1]
Coincidentally, the peak notch in the OP was the 1st subharmonic of that.
This is very common though, isn't it? Every child can hear a tube TV running when muted. Dog whistles too and all. And that's not even at the top of kids hearing range.
Does not being able to be around CRT displays because of the noise make qualify one as having super hearing? Pretty sure a good percentage of the population have that problem
Was tested while attending an electronic music class. Professor displayed everyone's result, so we could compare. His chart was the worst, as a cautionary tale. Too many live performance in front of the PA.
Coincidentally, the peak notch in the OP was the 1st subharmonic of that.
[1] https://en.wikipedia.org/wiki/Flyback_transformer