Brief summary of IEMs NA2 + :
Sound stage - Almost 3D, at eye level, the same depth and width. Good image and above average resolution. Exclusive for one DD at a price of 169 dollars!
Mid frequencies - very good with raising the upper mid frequencies. They are not sharp or screaming! Very fast transients - suitable for progressive !!!
Bass - very fast and textured, deep, but not for bass heads! There is more middle bass and less sub bass!
High frequencies - There is air, they are not sharp, but the upper highs are a bit dry. They are well tuned for the price range and more!
Dynamics - very good, excellent coordination, no overload with complex songs!
Cable - not bad, but I prefer Linsoul HC-08, a short review was made with it!
Resolution - unexpectedly good for this price range!
Recommended genres - Metal!
Recommendations - lowering the upper middle a bit and slightly raising the lower middle, a little more bass and slam - would be the perfect sound for me, but I still like it a lot!
Conclusion: Very good IEMs, with quality construction, very underestimated for metal music and progressive genres. I recommend, if it’s your sound signature - everyone may not like it!
Test songs for dynamics and overload : Ophidian I - Desolate (full album) 2021 - YouTube
Enjoy… 
Graph for good measure:
There’s more measurements with different tips. Seems that Tanya filters also tame the upper mids/lower treble peaks.
Thanks for your thoughts! How do these handle classical or instrumental music? Also, I’m a little treble sensitive - think I should avoid this? Thanks!
I never heard it, but judging by the graph, most likely, yes. High treble peaks without bass compensation might fry your ears if you are sensible like me.
I was impressed by the technical parameters I wrote briefly above. The highs are tamed a bit by changing the cable (with Linsoul HC-8) and a slight correction with EQ, change eartips. The strong point is the clean and fast transitions with enough guitars, and very fast bass! This helps people who listen to very dynamic and fast music, because most IEMs blur guitars! For classical music, I think some hybrids and tribrides will be better.
The treble spikes on these scare me ngl. Is this a case of an IEM performing well on complicated tracks but is not forgiving for poorly mastered tracks and longer listening sessions?
I have no idea. Never heard of it til now :o
That treble is a no go for me
Interesting, but I do not find the highs piercing. FH7 are more tiring with the highs! OG cable makes the sound sharper!
After trying many cables, I found that the best match is with the Теа cable! 
Spring bass!
Yeah I asked another reviewer on Headfi and that person didn’t find the treble too piercing either. Impossible to tell if it’s variation in human ear shape, unit / QC, source, etc. Bit frustrating as it makes it very challenging to make an informed decision! I want to be careful about how I spend 100-200 USD…
After burning 60-70 hours ----> the bass became a monster! The graph does not show this 
I wonder what will happen after burning for 200-300 hours ?! 
Prolly melt. You using an oven?
No, but I’m going to need ice to cool my brain
Today I listened to Oriolus Isabellae in a friend. Technical parameters: NA2 + ($ 169) > Oriolus ($ 600). Welcome to the world of expensive IEMs !!
Interesting to know, both because the Nm2+ is an all time favorite for me, and because the Oriolus has been a wishlist item.
NA2 + has better dynamics and a slightly better soundstage than Oriolus. NM2 + I haven’t listened to them.
Everyone tells me the NA2+ are only slightly different to NM2+, just a dash more warmth.
Just because you like some more expensive IEMs as sound doesn’t mean it’s an upgrade to another cheaper IEMs, Mr. Presenter. It’s like liking blondes and the others liking brunettes, but convincing people that blondes are better than brunettes!