Just got my NH today. Coming from a completely open Hifiman HE400i, driving with a Schiit Magni.
Started out positively impressed with the texture, though they were quite warm-sounding. Realized I had processing enabled in Foobar from yesterday. Doh... removed that.
After an hour or so, I'm quite pleased. My Hifiman is, I'll be frank, more transparent, though that could be simply because it presents the sound in a more "compressed way" (not to be confused with slow in attack or decay), ie lower volume sound isn't as far-away sounding/low, and is more easily heard.
The NH seems more dynamically "tall". If you imagine standing on the edge of a building looking down, the HE400i is a 10-story house where you can comfortably make out plants and details. The NH is a 80-story house as seen though a slight fish-eye lens, where the ground just seems to fall away more and it seems more elusive.
Listening to Meshuggahs "Nostrum", the timbre of cymbals and treble in general is, to my ears, much better than the HE400i. I think the strongest resemblance I got was to that of the Etymotic ER4. After some adjusting, it just seems entirely right both in tonality and texture.
Furthermore, 1 hour in, and these are, to my ears and with the amp I use, far from liquid or syrup-y. That's the terminology I'd use for slower attack and decay with a warmer EQ tilt. The NH remind me a lot of the Gr07, which is my absolute favourite IEM, and also uses Biocellulose material. It's obviously not piped directly into the ear, and the Gr07 has a slightly different EQ response, but they both seem fast and with that sandwich-paper texture.
Unlike my planar HE400i, the NH is sensitive to placement, and you basically have a gentle EQ at your fingers depending on how you place them.
No closed-back bass pressure, despite blocking some outside sound they feel quite open and un-pressurized.
Watching movies, they are more vivid than the HE400, textures can be harder, sounds seem more immediate. The T2 minigun texture sounds as dry and clear as ever. Overall the sound is wonderfully textured, and the surface is very fast and responsive and dry.
So far this is a real treat to listen to, like my GR07 but less "IEM direct", and with the wonderful timbre and transient-capabilities closer to an ER4. the EQ response after just 2 hours of adjusting already seems completely natural, and the balance is such that in most cases, most of the spectrum reaches "optimal" loudness simultaneously, and I don't find treble to be too far away or too upfront, plus with the way the treble textures, it's really clear and easy to "feel" even when not in your face. Like the Vsonic GR07, the upper-mids are stepped back just enough to fall back into line with the mids and lower treble, and most metal tracks (that always seem to have a 3-4K bump with most other headphones) sound balanced and leveled.
It's just a really comfortable sound signature, though I'm very much used to it after owning GR07s for a few years. In some instances I can feel like I'd like just a bit more in the presence range, BUT that same desire would also yield fatigue at the levels I'm using.
Coupled with awesome texture and perceived detail, I've pretty much been won over completely in 2 hours.
Ninja Edit: This treble is incredible. it's almost IEM-fast at times, listening to "Blood Bag" from the fury road soundtrack, it's incredibly uncompressed-sounding dynamics-wise despite being thundering bass.
Also adding more presence just doesn't seem right. I could maybe see an argument for dropping the mid-bass area 2-3 dBs, which I think some pads do, but that would also make me raise the volume 2-3 dBs, which would probably induce fatigue.
And despite being quite present, the mid-bass and lower mids just seem so open and easy, it's not the low-quality headphone slow, thick, impenetrable, fatiguing wall.