I am talking about listening fatigue, first of all, which is a long-term effect. Second, I think double-blind test are worthless, if they are done in isolation; first, you need to run non-blind tests, let people play with audio equipment as much as they want, in any combination, completely open; only after that, when people have figured out what to look for, run the double blind test. Forcing unprepared people to go through very subtle test surely won't give useful results.
If you can’t distinguish A from B reliably, none of the rest matters at all. The idea that you have to “figure out what to look for” is nonsense if you cannot distinguish the two reliably.
“Listening fatigue” when you know which is which is simply placebo.
You should probably read more attentively. I did not say you do not need double blind test.I said, once you learn what to look for, only that there is a point to do the blind test.