Knowledge Zenith (KZ) ZEX

Today we're going to review KZ's latest release on their budget lineup, the KZ-ZEX. I was quite fascinated by these because they have these cool faceplate and good color options and I got the Rosegold one to make things different
since this color way is new to KZ.

DISCLAIMER : THIS IS NOT A PAID REVIEW AND EVERYTHING HERE IS MY HONEST OPINION ON KZ'S IEM. THIS IS A REVIEW UNIT SENT BY KZ. Thank you so much KZ!

Build : ZEX has aluminium faceplates with a smooth matte finish and resin shells with a Dynamic driver + "electrostatic" hybrid drivers as well. What I don't like here is the nozzle especially the mesh cover since it looks thin but at least these solves the issue that some nozzles seem to pop out on some KZ models. I still like the metal mesh though.

Accessories : The unboxing experience with these pair comes with your average KZ packaging. Inside the box we have 3 pairs of silicone tips, and 1 attached to the unit itself which I recommend you to change because I did not like it myself. However, the new release of KZ's unit comes with these incredibly made cable unlike the braided one that comes with their older models, this is quite an upgrade of quality. This review unit came with a free foam tip as well.



Lows
The bass is punchy. Midbass bleed on the sub-bass and lower mids sections which make it sound fuzzy and warm especially on busier tracks.
These are probably one of KZ's best IEM with good and behaved bass when paired with good tips. Although, the stock tips are already good enough.
Mids
ZEX had surprisingly good mids especially on female and acoustic tracks, it has more emphasis on the upper mids without sounding too harsh to the ears. Lower mids can sound a bit thick and warm due to the mid-bass bleeding but it is not enough to make it sound muffled and still well presents well. It is actually rare to find these kind of mids on its budget range.
Highs
The highs on ZEX are rolled-off compared to their ZSN Series making these pair much more forgiving but detail retrieval is lesser on the treble region. But hey! At least you don't have to suffer from fatigue and harshness. ZEX has that crispy and smooth treble that doesn't sound fatiguing. So far, I haven't experienced sibilance on these pair especially when you use foam tips. I can use these pair for hours without fatigue.

Soundstage : KZ ZEX has wide and well-rounded soundstage making it very surprising for an IEM so cheap to have this wide stage.

Imaging : Has average imaging, struggles on busy tracks. But is clean enough to pick out the positions for each instruments.

Isolation : Little to no environmental noise, very great isolation. No sound leaks can be heard as well. Very great for commuting if you hate hearing the busy bustling of the city life.



To conclude this review, ZEX is a good piece made by KZ and a great buy to those who wanted an affordable IEM. Sturdy build, good cables, and amazing sound that you can buy that won't break your bank. I am currently using this as my main driver when commuting and it dos block out all the environmental noise and it looks good too! Good job for making this amazing and affordable IEM, KZ!

KZ is perhaps the most popular chi-fi manufacturer and in terms of sheer number of models available I think they got everyone beat. I did not keep up with their hectic release schedule for the better part of the year, but the KZ ZEX did catch my attention. Why, you ask? The EST (Electrostatic) buzzword, of course.

Most IEMs in the budget range go for a single-dynamic or a balanced-armature hybrid setup, so the ZEX is a refreshing change of pace. Let’s see if the sound quality is as good as it’s supposed to be.

Note: the ratings given will be subjective to the price tier. KZ sent me the ZEX for evaluation.

Sources used: Hidizs AP80 Pro
Price, while reviewed: $25. Can be bought from KZ’s Official Website.

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PACKAGING AND ACCESSORIES​

The packaging is no-frills but has all the necessities. You get 3 pairs of Starline tips (white) and a 2-core SPC wire. The cable itself is rather nice, especially given the price and how some manufacturers cut corners here. I wish there was a carrying case, but I am nitpicking here.
4/5

BUILD QUALITY​

The KZ ZEX have plastic shells (including the nozzles) with a metal backplate. The finish is good with no visible seam between the plastic shell and the metal backplate. At the bottom of each earpiece you’ll find the 2-pin port (protruted ones, sadly). There are no vents which is surprising given the existence of a dynamic driver inside. A pretty generic build overall but it’s well-executed.
4/5

COMFORT, ISOLATION, AND FIT​

Due to their lightweight nature and lack of vents, the KZ ZEX are very comfortable to wear and they isolate well. There is some pressure build-up but it only occurs occasionally. Not bad for a vent-less shell design.
4/5

SOURCE AND EARTIPS​

The ZEX is very easy to drive and shouldn’t need any special source to sound its best. For the review I primarily used the Hidizs AP80 Pro. As for tips, I used the stock tips and they worked well.

DRIVER SETUP​

KZ ZEX is a dual-driver hybrid, with a 10mm dynamic driver in charge of the lows and mids, and a 6.8mm “electrostatic” driver in charge of the highs. In reality, the electrostatic driver is a magnetostatic one and operates similarly to the principle of electret mics (just reverse-engineered). Despite the misleading marketing, the driver combination is quite rare in the budget realm and warrants a closer look.

TONALITY AND TECHNICALITIES​

The KZ ZEX has a V-shaped signature with the mid-bass bloom dominating the sound signature.

I usually start my sound section with the bass and then I go upward, but this time I’ll change things around a bit. The treble will be the highlight here for me because the KZ ZEX has a quite interesting treble response. In moderate listening volumes (around 70dB or so) the treble has a nice attack and sounds crisp without being overbearing or fatiguing. However, as you push the volume up, the treble becomes even more peaky ~5KHz and loses its composure.

I believe that this particular electret/magnetostatic driver is not suited for high SPL listening. So perhaps this is something to take note of when auditioning the ZEX. As for the midrange – it is not well-tuned. I am not a fan of the scooped out male vocals. Moreover, the upper-mids sound suppressed in high-pitched vocals, resulting in a boxy vocal reproduction.

The bass response, meanwhile, is mostly mid-bass focused and sub-bass rumble is not prominent. Bass lacks texture and has slow decay so bass notes can smear into each other. The emphasis on the upper-bass is a bit too much (rising from 700Hz almost) and this masks lower-level detail.

Speaking of detail, the ZEX isn’t particularly resolving even for the price. Dynamics sound compressed due to aforementioned upper-bass boost. Soundstage is below-average whereas imaging is basically left and right. Not much to write home about here.

Bass: 3/5
Midrange: 2/5
Treble: 3.5/5
Staging: 2.5/5
Imaging and Separation: 2.5/5
Dynamics and Speed: 2/5

SELECT COMPARISONS​

vs BLON BL-03​

The BLON BL-03 have been one of the few hype-trains that did not get derailed. It’s been a couple of years now that the BL-03 has remained the de-facto budget IEM recommendation.

In terms of overall build, comfort, accessories – the KZ ZEX are superior to the BL-03. The BLONs require a cable and tip change as the stock ones are horrible. When it comes to sound though, these IEMs go for different direction.

BLONs go for a slightly V-shaped tuning with warm mids and slightly rolled-off treble. The KZ ZEX on the other hand goes for a more pronounced treble response. In terms of midrange tuning and timbre, the BL-03 trounce the ZEX. I do think the ZEX has more sparkle in their treble. BL-03 bass is also more textured and doesn’t sound as smeared as ZEX.

Staging is middling on both whereas imaging is better on the BL-03. BL-03 also sounds more dynamic and less compressed than the ZEX. So apart from the treble, the ZEX is not really an upgrade over the BLON in most factors. Rather the opposite is often true.

CONCLUDING REMARKS​

The most interesting part about the KZ ZEX are their driver configuration and their treble response (in moderate listening levels).

Sadly, the midrange tuning isn’t up to the mark with overly recessed male vocals, and the bass is just slow and texture-less. The treble itself can get grainy once the volume is pushed up, so the ZEX have caveats all around.

The KZ ZEX falls victim to poor tuning decisions in the bass and mids despite having a fairly novel driver configuration. I hope KZ goes back to the drawing board and fixes the tuning issues in the upcoming model. For now, I cannot recommend the KZ ZEX.

Disclaimer : The unit was provided by ConceptKart as a part of a review tour. All thoughts and opinions are my own. You can purchase the KZ ZEX here.

Build and Fit
I wasn't expecting a metal chassis at this price point, but the ZEX has just that. The sheathing on the mic cable has a rubbery texture to it. As a result the cable is rarely tangled but it is impossible to wind them and stow them away elegantly. It's always a rat's nest. Fit is pretty standard, nothing worth noting in this aspect.





Amp Needs
ZEX is very efficient and it works fine off phone. No dedicated amplifier is needed.

Sound Quality
Mightily impressed by the budget offering from KZ, namely EDX, I was expecting an upgrade to the sound. The ZEX tuning unfortunately isn't what I would call balanced. There is a strong midbass boost which hits quite hard but it sounds bloated to me and it masks details and throws the sound off balance. There seems to be a peak in the treble region which adds a ringing to the cymbals and is quite unforgiving if the recording quality is poor on top of that.
One peculiarity worth noting is that the treble sounds a bit disjoint from the rest of the sound, it is not the last word in coherence. The treble seems fast and substantially resolving while the low-mid region seems to have slower decay. Speaking of midrange, the ZEX will not pair well with music that needs lush and open midrange reproduction, partly because the bass hump shadows it, making the midrange sound a bit veiled. However, this kind of sound (read : fun and enjoyable) might exactly be the thing that rocks your socks off. There are genres that can take advantage of this tuning and present a very enjoyable experience.





Conclusion
The ZEX isn't for people who are looking for a balanced sound; the tuning makes the ZEX sound quite colored with hard hitting bass and forward treble. Maybe that is exactly what you will want in your music if your music benefits from a tuning such as this.