KZ ZSN-Hifi Review

The KZ ZSN with faceplate all shiny and visible

If you haven’t been staying abreast of the recent developments in the IEM market, hoo boy, have I got some good news for you. For a while, I was strictly an over-ear guy. Then, sometime last year, I started receiving review units for IEMs. My realization of the sheer quantity of cheap, new, high-quality IEMs out there was a shocking revelation, akin to waking up from deep cryostasis in the year 3000. The KZ ZSN (KZ standing for “Knowledge Zenith”), a $23 IEM, stands at the forefront of this wave. I had heard of these before, but I never had any reason to purchase them. So when they showed up at the MajorHifi headquarters, I was excited.

Again, these are $23. Within the world of high-end audio, that price doesn’t typically get you much. Rarely are you going to get any refinement out of a product at this price. Typically, the best you’re going to get is something plainly inoffensive, with grainy but not loud treble, or recessed but not inaudible mids.

What a surprise the KZN is, then. And I know there are other earphones out there that pack a similar price-to-performance ratio, but the ZSN is the first I’ve heard of this category.

Granted, these IEMs aren’t perfect, and I’ll spend the rest of this review describing their imperfections. But I want you to keep that number – $23 – in your head for the remainder of the review. Because these are very good for the price.

The KZ ZSN all coiled up in a chaotic jumble

In the Box

OK, I have to tell a little funny story about these IEMs. Typically, our review units are either shipped to us from the manufacturer or taken from the inventory of our sister store, Audio46. These, on the other hand, were sent back by a customer in the box of a Final Audio E2000. It’s unfortunate that I’ll never have the true experience of unboxing these, but c’est la vie (I actually find unboxing rather unpleasant anyway, and I usually hurry through it).

As far as I could tell, these come with nothing but the earphones, a cable, and a set of extra tips (small, medium, and large). Am I going to bag on KZ for excluding a carrying case? No, of course not! Are you crazy? They’re $23, for Christ’s sake!

The KZ ZSN sitting on its side with the connector exposed

Build, Comfort, Appearance

KZ proves with the ZSN that there needn’t be any correlation between price and appearance, or price and comfort – they are very attractive, and very comfortable.

At a price this low, one would likely expect a mostly plastic-and-rubber build. Instead, the ZSN has an engraved metal faceplate and a body made of clear (although slightly murky) plastic, allowing you to see the mechanical particulars inside.

And one might expect a loose, fall-out-at-a-moment’s-notice fit, but for me, the ZSN sat very nicely in my ear. Once properly seated, it didn’t seem at all eager to fall out, nor did it create any uncomfortable pressure.

What else is there to say? The cable is fine. The connectors have this interesting semi-proprietary 2-pin layout where they slide into a little housing to prevent them from breaking or prying loose. Overall, the design of the ZSN is strikes me as solid and well-thought-out. No complaints here.

The caption on each earphone - (KZ) ZSN HIFI


The sound of the ZSN is broadly V-shaped, with an emphasis on bass and lower mids, and a sharp spike in the treble to inject “air” and “detail” into the mix. The result is a sound that isn’t entirely natural, but is quite pleasing for what it is.


Coming from your average $23 product, the bass of the ZSN will seem like a revelation – deep and powerful, without significantly muddying the rest of the mix. It goes all the way down to 30Hz easily, with a very slight roll-off.

That said, of course the bass isn’t the tightest or most articulate, and I did notice some distortion and indistinctness in my bass test track of choice (that being Tim Hecker’s “Counter Attack”). Again, what were you expecting? The bass is overall quite good, but of course it’s not perfect.


Of course, as a V-shaped IEM, the ZSN has a dip in the midrange. With these, the dip is right smack-dab in the middle of the midrange, centered at around 1-1.5kHz. What that means is that these have enough lower midrange to sound “full-bodied,” and enough upper midrange to sound “present,” but some instruments will be pushed slightly back in the stage.

There is a peak in the upper midrange that can make vocals sound kind of shouty, but it’s not an issue in most tracks.

Overall, I find the ZSN’s mids quite fun and engaging, but not entirely natural because of that dip.


The ZSN has highs that will probably come off as quite detailed and bright to those who are new to the world of audiophilia. To me, a veteran audiophile, they often sound rather peaky and unnatural – sometimes sibilant, sometimes hashy, sometimes unpleasant.

Provided I stick to less finicky music, the highs simply sound a little bit lispy, but not unpleasant. But with my more sibilance-prone music, the ZSN does lack some articulation in the treble region. It’s also missing some detail in the lower treble. I’ll say, though, that the ZSN boasts similar treble resolution to some IEMs costing significantly more, in the $60-$80 range, that I’ve reviewed.


The ZSN has a reasonably good soundstage – not impressive, but good. It offers reasonably good width, but doesn’t really get “out-of-head.” It lacks a bit of depth, as well, though it’s not the flattest-sounding IEM on the market, besting many more expensive options.

Imaging is, again, good but not great. It’s good enough to develop the impression of a stage in your mind, but the instruments’ positions are blurred, not entirely clear.

The two earphones of the KZ ZSN side-by-side, with more internal detail exposed

Pros and Cons

Pros: $23 price tag; attractive looks; engaging, balanced sound

Cons: V-shape not for everybody; somewhat lacking in detail across the board (but only when compared to more expensive IEMs)

In Conclusion

If you’re looking for a cheap, no-frills IEM that provides great sound quality for the price, the KZ ZSN should be on your radar. As with all headphones, they’re not for everybody: their V-shaped sound signature could be offputting to some, and at $23 they’re not going to be anybody’s “endgame.”

Still, if you’re just getting into IEMs, the KZ ZSN is a great place to start. They’re snazzy-looking and comfortable, and they sound great. What’s not to like?

Find the KZ ZSN on Amazon.

Technical Specs

Specification KZ ZSN
Driver(s) 1 Dynamic + 1 BA
Impedance 25 Ohm
Sensitivity 104 dB/mW
Connector 3.5mm to 2 x 2-pin


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Evan - that is to say, I am a composer of music that could be described as sad and fragile, or so weird as to be offputting, depending on who's asking. I've been excited about headphones for years now. Need to get in touch? Email!