There's a comparison between FD5, if you catch the drift translated.
https://zhuanlan.zhihu.com/p/341380452
Thanks a lot. Google Translate notwithstanding, was very good reading!
I'm going to have some fun with it...
Few points there are questionable:
"The low frequency of 3DT is not bad, it can only be said that a certain trade-off has been made, because common multi-unit dynamic headphones or coil earphones often use a larger moving coil as the low frequency unit, while 3DT is Conversely, it is actually
quite challenging in research and development." (I think the reviewer meant bold, daring) I however, am fascinated by UM daring designs. MEST first got my attention to the brand because of use of Bone-conduction driver to bypass dreadful ear-canal lower treble reflections that muddy spacial cues and damage imaging, but that is another story that belongs to a different thread... Use of smaller DD for bass in 3DT got my attention!
It's actually becoming common, when manufacturers of IEM with minimum venting, typical for brands that also offer custom fit, (as high level of isolation is expected) - chose to use smaller diameter DD (with longer excursion perhaps), more suitable for controlling canal air pressure and making IEM less dependent on fit and insertion depth. (kind of like BA) On this point I agree with the reviewer, that bass
has BA -like control, but the similarity ends there. Unlike BA, 3DT bass is effortlessly going very deep, deeper than any BA I've heard and level of impact is sooo good, - it's hard to mistake with many DD, forget about BA, not remotely there.
Sony in Z5 had to use a lot of venting or FR wouldn't be consistent, and it wouldn't be received as well as it was.
Contrast that to the bold(but foolish) decision of Obravo to put wrong type 9mm DD in completely unvented shell of Cupid. FR there is affected by the slightest movement and rendering it unusable on the go. Even BA in Cupid would probably be better than that abomination of a DD. Same goes for RHA CL2, but at least there was no better solution available, and it could be worse.
Many may remember the old "budget king"- KZ ZS5. It had sub-bass done by special 6mm driver, and ZS5 was rightfully praised for its bass control. .
My recent fiasco was with Thie Audio. L3 & L5(in lesser degree) DD is not properly vented internally and besides driver flex, FR response is also affected(at least for my ears
). I love Thie tuning but probably will avoid trying it again...
That brings me back to 3DT. I do get driver flex occasionally, so getting used to be more careful, especially with larger wide opening tips that pump air like a plunger
. Internal venting in3DT is sufficient, barely, but I don't complain because high isolation is worth it.
I think 3DT may put my FiiO FD5 out of business.
I don't want to start ranting about FD5 ergonomic failures here, that belongs to Fiio thread. Fiio have no driver flex but at the cost of isolation.
FD5 is less bassy, but similarly impactful. Sub-bass is slightly rolled off, but dynamics makes up for that. 3DT has more impact on the low end, Fiio might have slight edge at mid-bass, but it's close and likely an effect of 3DT sub-bass overshadowing similar(or greater) impact. I like tonality of both. Stage and imaging feels more precise with 3DT. Fiio has typical bit of stage haziness in all of their hybrid & DD IEMs. To be continued...