YU9 Audio (Fish 9) - U-554

I'd recommend the Yu9 Audio U554 if you want something with the small for factor and a sonion driver that is very detailed sounding. They can be bought off of AliExpress

I like that they included the old style ER4B tips. They sound Good. Thats all. Any questions?

The case is quite nice and very sturdy and premium feeling. It's slightly cushiony on top and inside it's like a the texture of a pool table. A nice thumpy snap when closed. In the box it came with 2 extra pairs of triple flange tips (different material), 1 pair of foamies, 1 pair of ER4B tips, and 2 sizes of double flanges, a filter removal tool, and a disposable microfiber cloth. The IEMs are quite beautiful and small in person. They clack just like marbles, and they have a surprising amount of weight to it, although I am quite used to regular Etys. The contorted and widened part of the yu9 u554 is a plus, as it provides extra stability compared to the bullet style Etys. It's a 2 pin. Uhhhh I think thats all, quite good value. It's like Ety if they met materialistic demands. Thank you Yu9. (also theres a winter sale for these right now. for me they costed 148 (tax included) but right now theyre 128.92 (no tax included so 140-ish for me, an American) )

I think the U-554 is most similar to the ER4XR in terms of Etys. The ER4XR is dead neutral, a BA benchmark, and very often boring sounding for many people. I think in terms of mids, it's in between an ER4B and the ER4XR. I think just the vocals/mids are put back a tinge to compensate which is nice. That XR bass shelf makes a really nice quick and tight decay on bass hits in songs such as "Too Long - Daft Punk". If you aren't ready for it, you may be disappointed. For Etyheads, it's true to the recording and very sastisfying The biggest improvement in sound for these is that most Etys are very dark for me. I've tried the ER2XR, ER3XR, ER3SE and ER4XR and I just wish they were all a touch brighter and I often have to put the Ety filters on them which unfortunately increases the pinna gain. The U-554 is not bright at all, but that bump is much needed in my opinion. Now compared to non-Ety IEMs, it's the usual Etymotic situation; it retains that distinct Ety sound that really has no true equivalent (whilst also actually meeting materialistic demands). The best way I can describe is to take a neutral and natural sounding (due to the bass boost and other colorations) IEM like the Zero:Red, and remove the naturalness entirely, and focus purely on being very clinical. Etys do not sound natural and the U-554 is no exception (from what I've heard the U-556 leans more natural supposedly however). Even with the treble bump, it isn't sparkly or spicy like something as the ~~Kiwi Ears~~ AFUL Performer 5. The treble is simply there, and the bass is just simply there, which is good for analytical listening. Very controlled, very deliberate, very clinical. I am pretty sure it takes a decent amount of engineering to make 1BA sound good (an example being the AFUL MagicOne). It does not respond well to EQ of course due to such. I feel as though the timbre is improved from the Etys as well; less "BA timbre".

I believe the U-554 has more pros than cons for certain. A con could be that it's a hollow resin shell instead of the Ety's full bodied aluminum shell, in which I think that comes into play in terms of durability and there is one picture online of the U-554 nozzle breaking (shown below from a CN/JP/KR forums \[forgot my linked sources\]) and also is definitely not scratch resistant. ~~Not unique to the U-554 that you have to be careful with your hollow resin IEM however, especially at that price.~~ It is definitely more DIY-like, cause it is. **update: I actually cannot find whether it is solid resin or hollow resin online. My U-554 has no ringing when tapped, is quite heavy, and has miniscule bubbles which could indicate that it is actually solid resin?! I sent an email to Yu9** (Heart-wrenching but I don't mean to scare you 🙁 I've switched through all my tips without a budge or scratch. This guy was clearly unnecessarily rough, I am positive. ) https://preview.redd.it/1zt1n6bo5zdg1.png?width=850&format=png&auto=webp&s=3fa6f38d5e94f2c32d322f997b5d985467128928 Ety's channel matching and QC is a gimmick in my opinion (on the ER4). I've had negative experiences for QC in terms of noticeable driver flapping/distortion/sound reproduction issues for the ER3, and so have others on Head-Fi for the ER4 (even for channel matching). This has especially started happening it seems since the acquisition of Etymotic from Lucid Audio, and when they moved assembly outside the US (around 2021 as I know). Customer service has also declined since then, however, if you live in the US, warranties and such will be a lot easier. At this point, I ultimately trust a competent Chi-Fi DIYer (especially Yu9) more than Ety as a whole but I shall see how the U-554 lasts in a couple months to a year. The no proprietary cables (\~$60) and filters (\~$25) feels insanely nice. Also the materialistic appeal is better as well :)