In this video I’m talking about the ZiSin (Zyins) 340, a ~$165–$170 IEM that I got as a “sample”… but I still paid a bit because I want to be as transparent as possible. I also call out pricing weirdness on AliExpress—depending on your country and sales, the price can get kind of ludicrous, so just be cautious. I go over the build first: a really pretty translucent red shell, flat 2‑pin, and an overall nice resin feel. Fit was fine for me (a bit small, not super snug), and the included tips/case are decent—though the case has a strong leathery smell. Sound-wise, the 340 is interesting. It’s got a thick, rich, meaty bass shelf and a fun midbass, but the lower mids feel undercooked, which can make the mids come across thin even if it helps stage. Treble is extended, sparkly, and detailed, but it’s also a little hyper with peaks that bothered me (notably around the upper treble/air regions). I walk through graphs, normalize talk (I don’t treat it like a real science), and compare it to sets like the ZiSin 336, Fatfreq Quantum, 7Hz Divine/Daybreak, Kiwi Ears Cadenza 2, and the KY Phantom. Where I land: it’s well-made and enjoyable for the right person, but it’s not for me—too much mid scoop with treble that doesn’t vibe. I give it 2 stars. The surprise standout is the “upgrade cable” they sent—premium look/feel (even if I don’t think it changes sound), and I’m keeping that cable forever.