Ne4 review/infographic getting postponed a little because I am deciding whether to go for a CIEM or not still. I won't go into the details too much for now but my personal feelings on the IEM: the Ne4 makes the Kr5 and Xe6 both feel like specialty IEMs - the 5 as a technical monster, and the 6 as a warm, thick and enveloping sound that somehow manages to maintain very good technical ability - the 4 almost feels like the IEM that FiR would recommend you if you couldn't afford the 5 or 6, of if you can't pick between the two, and want an excellent middle ground.
The 4 to me is both more resolving than the 6, and more musical than the 5, with IMHO the best bass tuning of the three. It isn't as neutral as the 5, and not as overdone/basshead-y as the 6, hitting that "somewhat warmer than neutral" sweetspot, a little like the A18s or A12t. It still benefits from FiR's best-in-class bass lows driver, but the texture is just a little less apparent to my ears (I might've just gotten used to it by now though) - midrange is reasonably forward, never shouty, but quite resolving - significantly more so than the 6, and maybe a little more than the 5. The treble is also an excellent middleground between the 5 and 6, where it's not as forward as the 5, not as dark as the 6.
I guess I like and dislike the same thing about the Ne4 - it is an excellent all-rounder, and definitely the most balanced IEM of the New Frontiers lineup, but it is also a fundamentally generic-sounding IEM tuning-wise. The quality of the bass and treble is phenomenal, but it doesn't quite match its bigger brothers - if anything the Ne4 reminds me of the Trio from 64A, but a refreshed version of it, with better SQ across the chart, and more technical ability. It's also reasonably similar to the Craft Ears Aurum.
Not 100% on it still. I only have the UIEM for a week, might be a better decision to purchase the universal for now, spend another several weeks with it, and maybe upgrade to the custom.
A less mixed-feelings impressions post:
Lotoo PAW S2
I'll save you some time with this one if you're reading diagonally - go buy one, this is one of the better
sources I've heard since joining the hobby. I am specifically saying source because a "dongle" to me has an almost derogatory term. I liked the PAW S1 as a PAW6000 placeholder when I'd forget to charge it, but that's what it was - an 80/90% of their entry-level DAP, with a very maleable pure-neutrality signature that would work with basically anything.
The S2 follows into the fundamental Lotoo philosophy that the coloration should predominantly be introduced from the IEM. That's what makes their stuff work so universally well with anything you plug into it, and if you aren't enjoying the sound you can comfortably say the IEM's tuning isn't for you. It is reviewer heaven, but more than that, for anyone who swaps their gear every few weeks there's basically no better alternative Imo.
It sports a healthy bass boost - I'd say comparable to the PAW6000, and maybe taking it a touch further. The Kr5 lows on it are phenomenal, and I can say the same about the Ne4/A18S/A12t. To balance that, the rest of the signature is quite clear and neutral, with a hint of midrange forwardness, as well as a very "liberated" treble response. It doesn't limit the highs the way the PAW S1 did both qualitatively and quantitatively, while being a little bolder in that region than the 6000, and moving away from that ultimate neutrality.
On technical ability it performs very well, while obviously not being able to expect the full DAP experience. Staging is reasonably wide and quite spherical, but falls short even compared to something like the PAW6000, which tends to stretch the sound further in all directions, especially the width. Separation and dynamics are good, definitely good enough for a walk with my dog, while detail is its strong suit, and among the better I've heard from portable sources (note: I'm not saying dongles).
Where the PAW S2 is in a league of its own to me personally is that it has me genuinely excited for my sessions with it. There's plenty of excitement in the signature, there's proper thumping bass and it doesn't sacrifice all technical ability and separation in the process (I'm looking at you LP W2). It doesn't force its signature on whatever you've plugged in either, so for the most part you still maintain the signature of the IEM, just a little spiced up by that clarity + bass boost.
The S2 to me isn't so much an upgrade on the S1, it's an entirely new product where Lotoo have gone for their most exciting sound signature to date, while still preserving their DNA. Even as someone that finds DAPs infinitely more convenient than dongles, the sound of the S2 is a big enough argument for me to choose to use it because of how stupid good the pairing with the Kr5 is. At 300$ before any discounts, I have not experienced better sound, and I have not experienced better value out of any source - in that sense it displaces the PAW6000 as my "value" recommendation.
Highest recommendation I can give any dongle