So lets see, 56 years old, growing up around small arms fire, trumpet player in marching, concert, jazz and rock bands through high school, rock concerts (up close and personal in high school, more reasonable distance in college and beyond), 13 years on a factory floor and oh yeah, a veteran Army Field Artillery officer. Did I forget to mention I used to be one of those folks who jumped out of perfectly good airplanes? Maybe a 13kHz threshold isn't so bad.
This makes me wonder tho at what point my hearing would make component quality a moot point? For example, I just finished building (and have started burning in) a pair of N1X's with Sonicaps, Mills resisters and Sonicap Gen II caps by-passing every cap. I did not use platinum by-pass caps. With my hearing issues I wonder if I would be able to perceive any difference between the Gen II caps and the platinum caps.
This issue also comes into play when choosing between speaker models as well as between upgrades i.e X-MTM, X-MTM Encore, N3TL, O3, X-Static, OB5, OB7, or one of the new models Danny is working on. Given that the listening room would be appropriate for either ported, TL or OB speakers, at what point would my hearing no longer allow me to hear a difference?
It's more than a theoretical question. Today my wife told me she wants me to build a new speaker system for the living room and she wants floor standers for the mains.

Now I have to choose the model and upgrade level.
Mike