I thought that "tuning" is just a variation of the Variations and the like...
I was on the go when reading your reply, my bad so I replied differently.
Yeah I mean Variations is one of few in the midfi that tuned like TOTL but Variations have rolled off treble extension and too scooped 200hz
That tuning (Dunu x Precog Mirai) actually resembles TOTL tuning that I heard in some TOTLs, so you're not wrong either they tuned similarly but thats the one of the best tuning.
1. Clean cut bass shelf, neutral until 200hz and never bleed on 100-150hz but have great punch on 50-60hz. Actually the sub bass 30hz is less heard but yeah bigger is better maybe
2. Less than +8db pinna gain, so it more balance and not shouty on upper mids and not too big gap from lower mids so mids aren't thin.
3. High extension, not roll off especially on 12khz and 15/16khz.
That 3 conditions must meet to have great TOTL tuning. Sounded easy but only few done it right.
Z1R, u12t, Annihilator, Monarch, Mest, Odin (little bit too shouty on 2khz), Tia Trio, Subtonic Storm, Helios have these 3 conditions meet. And thats TOTL tuning.
The Variations happen to be midfi IEM that have 2 conditions 1 and 2 but lack of no 3
Meanwhile harman tuned IEM also have similar tuning. Harman target is created from sample from 700 people or something, but not all of the are audiophiles.
Maybe this lead to personal preferences but I do prefer those TOTL tuning than harman tuning IEMs. Harman always too shouty for me.