Totally agree. I mean the fact that pretty much everyone who initially jumped on the Truthear hype-train, but then were persuaded to get off and actually preferred destination Maiky's EQ Mount (very close to Harman Hill, just within walking distance), realized the real truth was the Stock Truthear Train isn't all it's cracked up to be and chose not to get back on, speaks volumes (even after
-3.9 dB preamp gain).
And there it is. The probable main reason behind all this: hearing loss. From the Wikipedia
entry on NIHL (noise-induced hearing loss):
Which just so happens to be around the frequencies the Truthear Zero is elevated above the Harman target. Noise-induced tinnitus may also mask this elevation. Then there is presbycusis i.e. age-related hearing loss. Figure (a) below from his book shows Floyd Toole's own hearing thresholds over the years, and figure (b) shows the poor hearing thresholds of people with high variability (poor performance) in sound quality judgements, which is positively correlated with age:
View attachment 234680
As can be seen above, Toole's hearing ability has significantly deteriorated with age in the upper midrange / treble (again covering the Truthear's elevated region), and that's a good-case scenario, as he says:
And this age-related hearing loss influences treble preference, as Sean Olive has shown with his blind headphone listening tests:
View attachment 234697
I suspect if people's hearing ability was plotted against how 'shouty' they find the Truthear, there would be a positive correlation (and by extension an inverse correlation with age). So, if you're a younger listener with good hearing ability, you're likely to find the Truthear Zero shouty due to its elevation above the Harman target around the frequencies the ear is most sensitive, but if you're an older listener and/or with noise-induced hearing loss and/or tinnitus, you probably won't notice this shoutiness, because you likely have impaired ability to hear this elevated region of the Truthear's response.