I'm still waiting for him to prove that he validated his virtual reviewing process. It's his claim BTW that it sounds the same using EQ matching functions, I only asked about his process and his answers became increasingly defensive, but no more substantial. He often likes to question whether others have untrained hearing. He spends minutes in near every video reacting physically to products he's reviewing(mostly virtually). He doesn't come off as an objectivist to me, more a theory junkie subjectivist. He has made unproven claims that absolute phase reversal "increases soundstage".
It was validated in an AES peer reviewed paper by Sean Olive, Todd Welti, and Omid Khonsaripour
https://www.aes.org/e-lib/online/browse.cfm?elib=18462:
The one reservation I have with this is that acoustic impedance differences between earphones is not considered, but I qualify this in my EQ impressions. I do not claim that EQ'ing the magnitude response of one IEM to another using minimum phase filters based on 711 coupler measurements results in the two IEMs having the exact same magnitude response at my eardrums. The point is that the two IEMs will sound pretty similar, assuming a good seal. I find it easier to EQ an IEM with a smooth magnitude response to an IEM with a rough magnitude response rather than the other way around, likely due to acoustic impedance variances. If my Moondrop Variations EQ'd to another IEM has obvious issues, then I do not consider demoing the IEM in person worthwhile. However, if my Moondrop Variations EQ'd to another IEM sounds good, then I consider demoing the IEM in person worthwhile as there could be issues I did not identify, such as poor fit.
Regarding absolute polarity, I made several "informal" observations through both sighted and blind listening tests. I have successfully ABX tested absolute polarity with several commercial songs to confidence intervals exceeding 99.999%, so I can certainly tell the difference. For how I was able to tell the difference, one of the things I observed is that the soundstage appears to be "stretched" in a sense with inverted polarity, resulting in a "wider" presentation even though it sounds less accurate.