Review written by @Fc-Construct
Review units provided by Linsoul and KZ
If there is a brand that is synonymous with ChiFi, it would be KZ. Though now largely overshadowed by new competitors like MoonDrop or Tin HiFi, it is no exaggeration to say that KZ is historically responsible for the negative perception that accompanies Chinese audio brands of cheap, low quality, overhyped, flavor-of-the-month products released at a breakneck pace. Yet despite their poor reputation, KZ has legitimately done a service for those who simply cannot afford to spend more than the price of a nice meal on audio. In fact, you’d be surprised at how many live bands have adopted KZ’s IEMs for stage use given that they cost a mere fraction of the outdated but venerable Shure SE215s. While KZ may be seen as a blight by many self-professed audiophiles, I do salute their contribution to the hobby.
Introductory musings aside, the object of today’s review is the $35 KZ ZEX Pro that sports a hybrid 1 DD + 1 BA + 1 EST setup. This IEM is also known as the KZ x Crinacle CRN after an announcement revealing that it was a collaboration product with well known reviewer Crinacle providing the tuning. I believe the reasoning for this rather confusing naming situation was to gauge the community’s reaction to the KZ ZEX Pro before and after the reveal given KZ’s poor reputation and Crinacle’s respected name. But for the purpose of this review, the storied background of the ZEX Pro’s creation is irrelevant. What matters is its performance and if this collaboration will finally bring KZ time back into the spotlight.
What’s in the Box?
It seems like KZ’s packaging is the same as ever: a plain white box with nothing but the IEM, the cable, and 3 pairs of generic white silicon tips. It seems this time that KZ has provided a silver cable that uses their QDC-style inverted 2-pin jacks. This cable is actually pretty good with little cable noise or memory.
The body of the ZEX Pro is made of a translucent resin similar to many cheap IEMs on the market today. The faceplate is a fairly attractive zinc alloy that features the KZ logo. I have these IEMs in both rose gold and black versions. The Crinacle CRN version is same with the exception of Crinacle’s logo on the shell.
The fit of the ZEX Pro is surprisingly uncomfortable. Though it seems to be ergonomic and slots into my ear easily enough, there’s a bulge to the shell that protrudes towards the back of my ear. It seems like this extra bulk is needed to accommodate the dynamic driver. This may be a dealbreaker. At first it only irritated me but now, I can’t wear it for more than an hour at a time before starting to get uncomfortable or sore. Of course, your mileage might vary but despite how good the ZEX Pro may sound, I likely won’t be using it much beyond this review.
I had rather high expectations for the KZ ZEX Pro coming in given its frequency response graph that I had seen and Crinacle’s collaboration. But simply put, it’s not the game changer that some might have been hoping for. To be clear, the ZEX Pro is a good sounding IEM and almost certainly the best tuned product KZ has ever released. With a bass leaning balanced signature that will feel at home for most people and a price tag of $35, it’s a foregone conclusion that the ZEX Pro is worth the money. With that in mind, let me go through some of the nitpicks I’m less thrilled with about the ZEX Pro.
Frequency response of the KZ ZEX Pro and Crinacle CRN. Measurement taken with an IEC-711 clone microphone. Comparisons can only be made to other measurements taken by this specific microphone. A peak at about 8 – 10 kHz is likely an artifact of the microphone. It likely does not actually exist as depicted here.
Looking at the graph, there’s two ways you can interpret this. The first is that the ZEX Pro and Crinacle CRN are identical IEMs but have a minor product variance. The other way is to take the neurotic route and say that they are different IEMs or have somehow undergone so-called silent revisions. Personally speaking, I’d stick with the former.
The bass of the ZEX Pro is clearly elevated but not to the point that it overpowers the sound. It makes the ZEX Pro a bassy IEM with quite a bit of midbass and moderate subbass rumble. Bass notes are however fairly soft and blunted. Clean note definition and tight punch is not the ZEX Pro’s forte. There’s a slight bloominess and bass bleed into the mids as well. Though there is some level of bass texture here, it feels strangely dirty to my ears. Despite these gripes about the bass, I do think it does the job well enough while managing to avoid sounding generic or bloated like many other IEMs. I think I’d prefer a reduction of 1 – 2 dB across the board to clean it up a bit but that’s about it.
The mids tonal balance is well done. There’s plenty of lower mids on the ZEX Pro that take center stage of its performance. Instruments generally sound good and I have no particular complaint here. Vocals are where the ZEX Pro falters. There is a low level of the sibilance and harshness to the vocals. Traditional sibilance is characterized by a hard, sharp initial Sss sound. While this is present on the ZEX Pro, what’s more prevalent is a minor but harsh spike on the backend of certain notes. My complaint however is vocal timbre. It sounds strangely off to me, likely a result of the upwards sloping response and deadened treble. It's most noticeable when I compare it to a benchmark IEM like the MoonDrop Aria. There, it’s fairly clear to me that vocals on the ZEX Pro aren’t nearly as smooth or pleasant. To be clear, its easily better than your average IEM. But to call vocals great would be overselling it.
While the treble of the ZEX Pro doesn’t do anything offensive, it isn’t exactly amazing either. The lower treble transitions from the upper mids, tapering off by the mid treble and falling off in the upper. The ZEX Pro is not a dark IEM by any means nor is it necessarily majorly lacking in treble gain. However, the tone is bland and there is no shine or brilliance to it. Though the hats and cymbals are balanced in the sense that there isn’t a particular emphasis on either the attack or decay, they sound like an afterthought in the mix. This lack of energy makes the ZEX Pro sound mediocre in the treble.
Soundstage and imaging are average for IEMs, nothing outstanding. As usual with lower tier IEMs, there’s little depth or layering. Resolution and separation are good for the budget class but not ground-breaking given the proliferation of other very good IEMs in the recent year or so. I do find that the ZEX Pro does struggle a little with busier songs, particularly in the treble where it can start sounding incoherent. That said, I don’t think the differing driver technologies clash against each other and are seamless enough during transitions between the bass, mids, and treble. As a whole, the ZEX Pro’s technical performance is highly competitive for the price but doesn’t punch much above its class. IEMs like the MoonDrop Aria or Tin HiFi T3 Plus are still one step above the ZEX Pro.
Comparison to BLON BL03 and Tin HiFi T2
Undoubtedly, the biggest advantage that the ZEX Pro has over contemporary IEMs is its tuning. It cleans up the bloat and slight mud in the BL03 and T2’s lower mids respectively. The upper mids and lower treble region on the ZEX Pro is also superior to both as it avoids major dips and peaks. Though the vocal timbre on the ZEX Pro is wonky, the BL03 or T2's vocals aren't much better. From a technical perspective, the ZEX Pro also takes the crown by a small margin in terms of resolution and clarity. But if you already happily own the BL03 or T2, I wouldn’t rush out to buy the ZEX Pro until you have a real itch to try something new. And in that case, I’d point you towards the MoonDrop Aria instead for a more substantial upgrade.
Should You Buy It?
Yes, if you are a limited budget. I know I complained a lot during this article but that’s the nature of reviews. Regardless of if the KZ ZEX Pro was $30 or $300, I would have the same nitpicks. Where the ZEX Pro brings value is in its price. At $35, it further pushes down the price barrier for target-curve based tunings only found in IEMs of a higher tier. While the absolute price difference of $30 or so to the next price bracket for the MoonDrop Aria doesn’t seem like much, I’d like to refer back to the opening paragraph. Despite Crinacle’s collaboration with KZ, the ZEX Pro is not some sort of ChiFi messiah that some people may have expected. But what they have done is created a genuinely good product at a highly affordable price point. I’m certain that for many budding stage musicians or curious audiophiles-to-be, the KZ ZEX Pro will serve them well as their first set of IEMs. Just be careful of the fit in your ears.