Again, I hope KZ can make ZAX with a tighter DD like in Kryla or Castor.
The balance can be delicate, hopefully switches will help with fine-tuning to individual preferences.
As for the Truthear, I am personally not sure how much KZ should go there into the "tuning by the curve".
I have Hola and Hexa.
I really like Hola tuning, that is bass and mids. Treble is limited/poor, and it may be fair that for $20, one does not pay for the treble....
Hexa has a great resolving treble, but then bass is just not any fun - perhaps for $80, the engaging bass is not included.
Idealistically, one may hope that in their next $100 IEM - Truthear may get both. I am personally not willing to try after Hexa and Shio (a disappointing DAC). I will better stick with KZ.
Actually, looking at Trifecta (and sharing my impressions here)- 6 Ohm (!!), 3 DDs in a strange triangular arrangement relative to the nozzle. To make these DDs to sound in-phase surely requires a flagship-level effort, and many still think that it is not there. Then some just love this less-coherent, but fun IEM....
Anyhow, KZ always delivered fun, (one way or another) so here is a great/golden opportunity for KZ to transcend from earlier CA imitations to full-blown supremacy by "beating Trifecta at about 1/100 of the cost), by simply building on a Castor with 2-3 more smaller DD axially arranged similar to DQ6. This design will be naturally simpler with the coherency, and a lot of fun can be unleashed