Quick but necessary update:
At home, compared 3DT to MEST.
Ok. I've got to admit, I got carried away, probably due to my very reserved expectations of 3DT.
MEST is indeed on the next level. It sounds more full, more smooth, more natural and more open. (not 4x though) I've got to watch out my hearing changes and always compare at the same time, not from memory.
Before receiving 3DT I was listening to Volt all morning and while I like Volt competent well rounded presentation, 3DT was like a blast of fireworks, so refreshing. At least it does sound more open than Volt, that due to its warm presentation cannot sound too airy and open.
I think 3DT didn't defy graphs completely. It does remind me Mofasest Trio, with lighter airier mids and treble, but 3DT lower treble is more tame and not masking treble extension in the same way. Trio I had to mod with some foam to reduce lower treble, but, at least today, don't feel need to do anything to 3DT.
3DT also sounds like Moondrop Blessing2 should've been tuned, closer to S8 but with more dynamics. Only unlike BL2, it has excellent dynamics and again - more reasonable lower treble.
Otherwise I'd say Moondrop BL2, S8 & Trio, share the same
neutral-cold light and airy tonality, while MEST, FiiO FH7, iBasso it07 -
warm-neutral. Volt, obviously is pushing warmth to a new level, and IMR Semper - farther to the crazy territory that even hard to describe.
3DT is an worthy addition to neutral cold group of IEMs. Might actually be the best of the 3. Will see...