I'm surprised, folks... I discovered only a few days ago I'm not 100% human: I'm some x% of a bat DNA;-)
To my very surprise, I added to 4-ways Gotorama a cheap dipole ribbon (super) tweeter, good as per specs, up to 25Khz.
I may declare - your honor - Gotorama is now a 5-ways multi amped system...
... but... what's the matter?
Do I need a 5th way?
Do I hear up to 25Khz?
Is there any instrument going up-to 25Khz, actually?
The answers to the three above mentioned questions is: definitely Yes! for all the above.
Seriously: I'm not a bat, of course... despite my middle-age ears and hearing capabilities, well... myself, as everyone, may actually perceive much higher frequencies as the canonic 20-20,000 hz!
With age, we get some aid from Mother Nature - i.e. lynx-like hairs grows on ears and they sure have a function in hearing, better, perceiving sounds... and let's not forget my/our decades of listening experiences which sure counts.
The highest frequencies are - now I've the proof - very, very, very important: don't believe in who states they're happy with a romantic (rolled-off) sound!
I'm also very happy with my B&O portable radio sound, folks... but - 'c-mon, don't fool you, romantic self-forgiving listener! - when I listen to Gotorama, I now feel (perceive) and appreciate the added, barely audible top-end isn't only a magnifying aid to triangle, assorted bells or shimmering cymbals, BUT... you feel everything with a sense of completeness: the wind instruments attacks, the decay of cymbals, the recording venue bloom... the oomph!
The Goto SG-160 gently rolls off at 16Khz and sure at 18Khz is only suggesting upper-harmonics of high pitched instruments.
So, please, don't ask, yet... I - like many other - hear and feel more and more of what's hidden in grooves... thanking a cheap gizmo, an added dipole super-tweeter.
Better late than never... that's that ineffable "quid" which makes our passion worth, day after day, year after year!
An Epiphany!