I would like to add to that our subjective experiences remain mostly the same overall although they might improve continue to evolve individually. ie even for the next generation the overall subjective experience limit will not change much . It will of course be limited by or change due to our own evolution as humans.
Objective measurements will mostly only continue to improve which is the very nature of science ie
we will get better and better every-time we find something new and at some point, in the future, be able to
measure everything about something but
not everything about everything since that is absolute knowledge..and a philosophical debate !
As an example in audio itself , audiophiles had been for a long time been talking of differences in digital outputs and then only later we were able to measure jitter and explain it,. Today jitter is an absolutely measurable standard and can be take as one basis where unless you are good at hearing , your ears may mislead you to choose a cable which sounds good but may be distorting in a good way.
Similarly we do not really have all the reasons for the same for a speaker/amp etc. Maybe some day in the future but not today. but our measurements will only continue to get better untill we will.
Personally believe that the moment we end us saying that we know everything and can measure it all science will stop ! hence but nature of science there is always something more to measure and ergo we cannot measure everything, But again what we can measure we will use.
Science is to prove better to us what we experience with facts and experimentation.,.saying we can prove everything today can only be arrogance and is actually anti science !
i would love to be shown anything wrong in my perception since that only contributes to my learning !
Just to clarify what I was saying is that there is musical content above and below the normal human listening range which cannot be heard by the ear but can be felt by the body. I am aware of some aspects of psychoacoustic perceptions like how our brain can reject audio and visual signals which we have evolved over the years due to so many reasons including but not limited to our survival especially around imaging and rejection of signals.
All of us can feel the effect of bass below 20..we all do at some level on a daily basis at some time,.
not all of us may hear the above 20khz sicne perhaps those signals itself are rare but it is a measurable phenomenon and may have been studied and measured in various ways ( perhaps for
tinnitus, not again not sure of this area.. i have heard it what i think is that ( by a simple on and off of a supertweeter) personally not a fan but yes you can discern it,