Этот обзор на русском.

I’m watching products of the EPZ company with interest — at least because I see a certain logic, a certain vector and progress in what they’re doing. They seem to be one of the few Chinese companies that don’t try to produce headphones on a catch-as-catch-can basis, but purposefully and consciously evolve theur product line towards really good sound.

Today, we’ll talk about EPZ K9, multi-driver in-ear monitors that go for some $300 on AliExpress and already for 18,000 rubles (some $225) on Russian marketplaces (as of July 19, 2025). K9 are presented in two decor versions, a shiny one and a black one. I bought the shiny one.

All but the sound

The earphones come in a smartly decorated box of Celestial quality. No pun intended!

Here’s what’s inside:

1. the earphones themselves;
2. a set of 6 pairs of eartips;
3. a cable;
4. a case;
5. some papers.

The case is very beautiful, but dumb, you know.

The cable is similar to the one included with EPZ P50, but the braid is now fabric, black in color. Again, the retainer ring (locking nut) is completely flat and polished, but it runs normally this time. The cable has replaceable 3.5 and 4.4 mm angle connectors.

There are two types of eartips, made of plain silicone and thermoplastic elastomer. They have approximately the same outer and inner diameter. There’s no difference in measurements between them at all.

The earphones themselves are assembled according to the scheme ‘1 dynamic driver + 8 armature ones’. All this grandeur ‘floats’ in molded polymer resin enclosures.

The design of the exterior surfaces of the enclosures is a clear allusion to butterfly wings. Burnt foil is covered with transparent silicone-like material, which, in its turn, is placed under steel plates. The result is unusual and recognizable at least.

Naturally, since the steel is chrome-plated, fingerprints appear on its surface immediately after opening the box.

There are no other distinctive features of the enclosures. A single compensation hole is on the back.

I didn’t find any ergonomic nuances in K9: the size of the enclosures can be classified as average, the earphones fit perfectly in the ears, and the cable doesn’t fall out. Chamfers could have been made on sound ducts, which are already not too long (4.6 mm). On the other hand, with 5.7 mm of thickness of these sound ducts, almost any eartips hold on them relatively well just due to friction.

Personally, I used K9 most of all not even with my favorite Zhulinniao Zhu Rythme, but with weird SHANLING SE100 (eartips with metal ‘propellers’, here they are), as well as with Rose Techniques Soundcocoon/SC (here): they cling to smooth sound ducts perfectly and make my ears feel very comfortable.

The sound

You can read about my measuring rig here. Listening was performed through RME ADI-2 DAC fs and Moondrop DAWN Pro.

Frequency response of EPZ K9:

The tuning looks very reasonable:

• it’s generally similar to the Harman curve rotated clockwise;
• the bass is slightly raised, but balanced by an emphasis at 8 kHz;
• the middle is smooth in terms of the Harman curve, but muffled by an average of 1.5 dB;
• the ultra-high frequency range is neatly emphasized.

K9 have a finely balanced, slightly V-shaped sound delivery, but with that, the frequencies after 10 kHz are not ‘hidden’ from the listener – you can always hear them in any track. You can call it ‘lightness’, ‘detail’, ‘technicality’, but the essence won’t change: K9 clearly and freely play the ultra-high frequency range, however, not going beyond the bounds of all reason.

And here we can argue about the versatility of the sound delivery whether it’s possible to listen to metal or only to live instruments and academic music with K9. However, I would go from the other side. I would proceed from the quality of recordings and the manner of mixing: for example, Amarante will hardly be pleasant to listen to, while a lot of pleasure can be obtained from creative works of Shexna, Jesús Molina or Khemmis if you are ready to clearly hear cymbals and other similar instruments in music parts.

As for the sound stage and virtual sound source positioning, K9 don’t not break records here, relying more on the scale of the sound image and the frequency balance. If there is width and ‘air’ in a track, you’ll hear everything there.

And let me note, um… kind of scaling of the sound delivery depending on the volume: at high volume, K9 hit with a subbass and are actually able to throw a party, but you get tired of this within an hour or two of such listening, while at normal volume, K9 just sound so comfortable that you can listen to music in them all day long, which again indicates a competent approach to tuning and a deliberate frequency balance.

By and large, I have no complaints about the K9 sound: it’s great. The tuning is universal in terms of suitable musical content, and the sounding is comfortable at any volume. Yes, the tuning has its own features, but these are features, not faults.

Nonlinear distortion at 94 dB with the ‘Use harmonic frequency as ref’ option turned off and on:

Same for 104 dB of volume:

Minimum phase response, group delay, and spectrogram in the ‘Burst decay’ mode:

I have nothing to comment on here — the earphones are technically excellent.

Comparisons

Looking at the known rating and taking into account current prices, it’s easy to choose decent models for reference:

Frequency response of K9 compared to Lethuoer Cadenza 4:

Just from the charts, you can guess that Cadenza 4 sound, if not ‘lighter’, then noticeably sharper than K9, which can be attributed neither to advantages nor disadvantages – this is a feature suitable for certain music styles and taste preferences. I’ll note that K9 win in terms of versatility and fit: Cadenza 4 have a somewhat controversial shape of enclosures, especially when it comes to the angle of the sound ducts in relation to the enclosures.

Frequency response of K9 compared to Moondrop Blessing 3:

The sound of Blessing 3 is noticeably sharper and drier, whereas K9 are slightly ‘warmer’ and more distinct after 10 kHz.

Frequency response of K9 compared to Kiwi Ears Orchestra Lite:

Orchestra Lite’s sound delivery is still unique, placing a premium on the midrange. Orchestra Lite bring the sound ‘closer’ to the listener, they are a little airier, and the guitars and voices are sharpened, while K9 are warmer, their sound is more ‘massive’, ‘dense’, and calm.

Frequency response of K9 compared to Kiwi Ears Quintet:

Quintet sound louder and angrier at the account of the middle and subbass. K9 are slightly warmer, calmer and ‘wider’ due to the nuances of the sound delivery in the range of 10 kHz and above.

And here is a special guest of the today’s review. These are the IEMs that normies don’t even know about, and even not all audiophiles had an opportunity to try them on or just to hold them in their hands: Moondrop Solis II, 10-driver monsters in silver enclosures weighing 23 grams (each) and costing $3,000 (per pair, thank God!). Released in 2023, they are still the crown of the Moondrop line, as well as their most expensive headphones.

Sergey, thank you for letting me try them on and measure them.

So that’s what I’m driving at:

I’m not saying that K9 and Solis II sound the same. But I categorically insist that, with the exception of the ultra-high frequency range, these models are tuned very, very close to each other at the range of 10-15 kHz. Actually, the only obvious difference perceived by ear is the delivery of the aforementioned frequency segment: K9 slightly emphasize it, while Solis II, on the contrary, reduce it. And, quite frankly, it’s hard for me to say which of these sound signatures I prefer.

Something else is important, and I won’t stop talking about it: good sound keeps on falling in price.

Besides, I’d note how important it is to write reviews not about ‘spherical headphones in a vacuum’, but always to see the context and put the model in question in it. And the broader this context is, the better for the consumer. In contrast, manufacturers break their necks trying to address each of their models as if they’re in a separate filter bubble, and nothing else exists besides them.

Why? Because it’s easier to sell this way.

Summary

As a reminder, the previous EPZ model, P50, ‘failed’, from my point of view. More precisely, it turned out to be mediocre as against competitors, as well as had some sound tuning failures. And here come K9: a similar kit, nearly the same price, and much more conscious, ‘mature’ tuning. And I personally congratulate EPZ on this model, for what it’s worth.

These earphones have taken their place in my rating, and this is, you know, really something. This is a model that acts as an indicator of the fact that EPZ can do things in a big way. The earphones turned out to be excellent, versatile enough in sound, conceptually clear, comfortable, visually recognizable, and different from competitors in sound delivery and design.

To buy or not to buy: to buy, but with due account for the specifics of the ultra-high frequency range delivery.

Good job, EPZ! I’ll be keeping a curious eye on them.