Well you neatly avoided the question there. Do you think signals above the audible range of 20kHz at - 85dB are audible?
We can measure things that are of no consequence and way below our ability to hear.
Given for example said 22.8 kHz, and it's aliasing product at 21.3 kHz, it is not down by -85 dB in this case. And yes I consider 21.3 kHz likely audible for notable portion of population on earth (at least more than 1 out of entire population).
But again, I don't evaluate audibility of N within population X people. That is much harder evaluation to do than just fixing the problem, instead of speculating about audibility. More, evaluating audibility of some objectively found problem is trying to find excuse for not fixing an obvious problem.
If you ignore the real world then what you are doing is somewhat arbitrary.
How am I ignoring the real world? If I can fix something I can find, objectively, as fault in real world, I will fix it.
Can you describe why you are against fixing some obvious problems?
For me, this is non-issue. It is one of the many things I've fixed already and I move on to many of the other issues to be fixed. No need to make a lot of posts about one particular fix, which is among the easier ones.
No, you are conflating amplifier performance with other issues. If the amp has good IM performance, it's a non issue.
In real world (pun intended) not everybody has a perfect amplifier... How about playing nice with those with less than perfect ones too?
Otherwise we very quickly move to talk about amplifiers and then I start hearing statements "if a DAC has good quality it doesn't output ultrasonic images". Just IMO, you cannot push problem of component A to shoulders of component B. Every component has enough of design challenges in it's own domain.
If it has IM problems with signals in the transition band then it has issues with IM in the audio band. It's a shit amp - period.
I don't see it that way. Usually 2+3 kHz twin tone is quite different from 19+20 kHz win tone, both have the same 1 kHz difference.
But really, I don't know why I'm having this conversation. It is off-topic, except for the nice detail that with properly done DSD content you don't have digital decimation filters (so whatever we discuss doesn't exist)... You can make you own decisions about what is important to you and I make mine. When I can objectively measure differences, I'm usually fine talking about those, from mathematical perspective. If you want to tell people what they can and cannot hear, it's your decision. Personally, based on my experience, I don't do that. People have surprised me enough many times.