KZ X Crinacle CRN (ZEX Pro) wired IEM review

Prasad, 13 February 2022

KZ is a Chinese brand that has become well-known in the IEM segment for its affordable and reasonable-sounding earbuds. We covered the popular KZ ZSN Pro X in our budget IEM roundup and found them to be the best of the bunch.

The company has now teamed up with Crinacle to launch the CRN. Crinacle is a revered reviewer and critic in the audio industry and runs a database of over 1000 tested IEMs on his website. Recently, he has taken to doing collaborations with IEM brands to come up with products that have been tuned to his liking. KZ now joins this list of brands that includes Moondrop, Fiio, Fearless Audio, and See Audio.

KZ X Crinacle CRN (ZEX Pro) review

The interesting thing about the CRN is that they had previously been launched as the KZ ZEX Pro without the branding, even though it's the same product. Crinacle revealed later that this was a social experiment to see how the product would be reviewed without his branding before releasing the version with his name on it.

So even though this review will refer to the product as KZ x Crinacle CRN or just CRN, it's also applicable to the ZEX Pro as the two are identical, minus the Crinacle branding on the latter.

So what is this product, then? The CRN are a pair of affordable IEMs. While KZ tends to have its own tuning for its IEMs, the CRN has naturally been tuned by Crinacle, with the goal to have a more balanced sound profile with a bit of bass. That sounds like an instant improvement over the typical KZ IEM and it may very well be the case. Let's see, however, how the CRN actually perform.

Update: Since publishing this review, Crinacle has distanced himself from the CRN due to his disagreement with how the drivers are tuned (more on this below). However, while he no longer approves of the product in principle, the earbuds remain the same and thus the review below remains valid.

Design and build

The CRN are a first of their kind earbuds from KZ featuring a triple driver design comprising of an electrostatic, dynamic, and balanced armature driver in each earbud. To be specific, it's a 6.8mm electret electrostatic driver, 10mm dual magnet dynamic driver, and a Knowles 30095 balanced armature driver.

KZ X Crinacle CRN (ZEX Pro) review

For a brief explanation of all the driver types, an electrostatic driver works by vibrating a membrane suspended in an electrostatic field. A constant (and usually high) voltage is passed through the membrane, which then moves based on the changing electrostatic field from the conductive grids on either side. An electret electrostatic driver has a constant and usually small voltage pre-applied to the membrane and thus does not require a powerful external power supply to work. This makes it suitable for form-factors like IEMs.

A balanced armature driver, on the other hand, works by moving a diaphragm by attaching it to a reed or armature, which is suspended in a magnetic field. By magnetizing the reed, it can be made to move up and down, thus moving the attached diaphragm.

A dynamic driver is a simple conical diaphragm attached to an electromagnet (voice coil) and placed in front of a permanent magnet.

All these driver types have their advantages and disadvantages, so they are usually reserved for handling different parts of the frequency spectrum using crossovers. In this case, the dynamic driver handles the bass region, the balanced armature the mid-range, and the electrostatic driver the high-end.

Update: While the above is true in theory, as it turns out the BA and electrostatic drivers in the CRN are extremely dampned to the point of being barely audible. The only driver you are mostly hearing is the dynamic driver and as such KZ's claim of this being a triple-driver IEM is misleading. This is the reason for Crinacle's disowning of the product, as he was under the impression that it's a proper triple-driver design.

To contain all the drivers, the shell of the CRN is on the larger side. The outer cover of the shell is made out of zinc alloy while the part that sits inside the ear is translucent resin. Build quality is good and the earbuds feel well-made regardless of the price.

The CRN come in two colors, rose gold, and black. The gold model has clear resin instead of the translucent on the black.

KZ X Crinacle CRN (ZEX Pro) review

The earbuds feature a standard 2-pin connector. The bundled cable is relatively easy to get on, although the L/R marking on the cable isn't easy to see so make sure you get it right as you have to attach the cable yourself the first time. Play a test tone if you aren't sure you got it right.

The cable itself is pretty good. It's not too thick nor too heavy, doesn't maintain kinks and folds easily, and also doesn't have any appreciable microphonics.

You can choose to buy the CRN with a choice of two cables, one with and the other without a mic. The mic version also has a single button to play/pause playback and pick up/cancel calls and works fine on both iOS and Android.

Aside from the cable, the only other things you get in the simple packaging are the three sets of earbuds in different sizes. These are standard silicone ear tips; no fancy foam here.


Despite the awkward-looking shape, the CRN were quite comfortable inside my ears. The resin shell has carefully designed indentations to go around the contours of your outer ear cavity.

KZ X Crinacle CRN (ZEX Pro) review

Whether these fit your ears exactly will depend and it's possible not everyone will find them comfortable. The shape of the earbuds relies heavily on guessing the size and shape of your ear so it's quite likely that it will miss the mark for some users.

The supplied earbuds are also soft and comfortable on the ears. They also create a really good seal, bringing down the ambient noise levels quite a bit without involving any software trickery.


Audio quality

Update: Regardless of the truth about the driver situation mentioned above, the analysis below is unchanged and remains valid.

The CRN have been tuned to deliver a mostly neutral sound but with a bass boost. The resultant sound is pretty much as it says on the tin.

KZ X Crinacle CRN (ZEX Pro) review

The bass tuning and performance is one of the better ones I've experienced on IEMs in this price range. Most often, the bass boost starts much earlier in the frequency range, which tends to also lift lower mids and upper bass frequencies, resulting in a very mid-bass heavy sound that can be boomy and unpleasant.

The CRN bass boost starts at around 200Hz and it's really only below 100Hz that it kicks in. This produces a cleaner and purer bass boost shelf that lets you enjoy your bass frequencies without affecting the rest of the sound.

The bass on the CRN isn't as upfront and in your face as from a typical mid-bass boosted IEM. It really comes down to the sort of music you listen to because not all music has a lot of energy below 100Hz so at times it feels like there isn't much bass boosting happening. This does work quite well for the most part as music that is generally not intended to be bass-heavy is left largely untouched aside from a bit of added warmth.

KZ X Crinacle CRN (ZEX Pro) review

On the other hand, tracks that are bass monsters can absolutely revel in that surfeit of low-end energy as they thump and slam to glory. Bass delivery remains clean and distortion-free and the drivers are able to deliver the sound quite well without bottoming out. The bass also never feels overtuned; the intent was clearly to enhance and not overwhelm.

The mid-range performance is great. The response across the range is incredibly even, which means all frequencies in this range are getting exactly the amount of energy as they should in the recording. Vocals have a great presence in the mix along with percussion and string instruments coming through beautifully.

If anything, it's the nature of the balanced armature drivers that sort of taints the sound a bit. BA drivers don't have the most natural tonality or timbral characteristics and you get this slight nasal or metallic tone to some of the vocals and instruments. It's only something you really have to pay attention to notice, however.

Treble performance is also really good. Most of the treble range is really even and although there is some unevenness in the higher ranges it doesn't really come through in the sound. For the most part, treble on the CRN has just enough energy, brightness, and sparkle that the recording demands and almost never feels shrill or shouty. The sound does seem to roll off around 15k, though, so you're not going to get much out of your high-resolution recordings, not that most people can hear above that, anyway.

KZ X Crinacle CRN (ZEX Pro) review

Technical performance isn't as impressive and more indicative of the price bracket we are in. Resolution and detail definitely feel lacking here compared to more expensive models and also rare exceptions like the Moondrop SSR, which are similarly priced but can resolve much more detail. The imaging performance is quite good for IEMs, no doubt helped by the strong upper mid and treble performance. Soundstage is expectedly underwhelming.

Regarding sensitivity, you really can just drive these using the headphone jack or dongle on your phone. While most of my testing here was done using a Shanling UA2, the Apple Lightning to 3.5mm headphone jack adapter was also perfectly capable of driving these earbuds with plenty of volume to spare. These are sensitive enough to expose any background noise that may be present in your source.


The CRN can be configured with or without a microphone. My recommendation would be to not get the microphone as it's just not very good. The sound is awfully quiet for some reason and I wasn't really sure if it was just my unit or an issue with the cable.

KZ X Crinacle CRN (ZEX Pro) review

If you don't get the cable with the mic, you always have the option of getting a different cable with a better mic.


The KZ X Crinacle CRN or the ZEX Pro are priced at around $36. These are exceptionally good value IEMs with one of the best tunings I've heard in this price range. They stand head and shoulders over their competitors in this price range, many of which actually come from KZ itself but don't sound nearly as good.

KZ X Crinacle CRN (ZEX Pro) review

The technical performance could be a bit better and the microphone is an afterthought but neither is a dealbreaker. Those were the only times I was reminded of the price of these things because it was really hard to tell otherwise. Even things like the build quality and the supplied cable are really well done. I also found them to be quite comfortable to wear but your mileage may vary on that.

Overall, the CRN get a strong recommendation from me and are absolutely worth your consideration.

Thanks to Headphone Zone for providing the review unit.


Reader comments

  • mlerp
  • 22 Jan 2023
  • gIP

i had a similar issue with mine going quiet after some time, usually stronger in one ear than the other. turns out its because their innter tips are much smaller than most other IEMs, they tend to slip deeper inside your ear, which makes them pr...

  • Samie
  • 21 Jan 2023
  • XRI

Which one of the sennheiser & beyerdynamics headphones did you use to test? And which is better?

  • Zako
  • 14 Sep 2022
  • spi

What would some of those headphones be?

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