Review - Hidizs S8 Pro Robin

Review - KZ ZEX (sub 50€)

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Also available on YouTube in Spanish: Acho Reviews YouTube


It has been a while since I tried any of the latest offerings from KZ and I somehow stumbled across the ZEX when it was announced for preorder. As it was a new combination of drivers from the brand and was at a very reasonable price, I placed the preorder and actually forgot about it.

It sat in an unopened box for a while until I saw somebody mention it on a forum and decided to check if I had actually received it or not (I had quite a few unopened boxes laying around). It was indeed there and I decided to give it a quick listen, I must say I was surprised at the first listen, so I put it on the burn-in rig and gave it the usual time before grabbing it again this week to test more.


Not much has changed in the KZ presentation, in fact, I don’t think anything has changed since the last time I opened a normal set of theirs. I mean, there have been a couple of “special” presentations, such as the ZAX, but this is just like any other of the many KZ offerings that have been across my desk.

A simple white box from which slides a tray with a clear plastic cover, showing the IEMs inside. Underneath this we get 3 pairs of silicone tips (including the ones installed), the cable and, well, that’s it.

Build and aesthetics…

While the shape of the ZEX is the same usual shape used by the brand, they are a little smaller than things like the ZSN range (only slightly), being the same size as the ZAX but with a bit more contouring going on. They actually look fairly decent for a set of IEMs that cost around 20€. I am not sure if the faceplate is plastic or metal but if I had to guess, I would say plastic. Overall I like the look of them, fairly discrete but without being too boring.

As far as the cable, well, here KZ have made a huge improvement in my opinion. Ok, it’s not a boutique cable with fancy braiding but it is miles ahead of the thin twisted cables that I was used to receiving from the brand. They haven’t even really done much to improve it, they have just covered a thin cable in a see through rubber coating, but it is enough for me to not want to throw the cable in the KZ pile upon opening the IEMs. My version has an inline mic and I am not sure if I ordered it like that on purpose or by mistake (or maybe that was the only one available for pre-order at the time) but it’s a shame as I wouldn’t mind having this cable mic free for when I use other KZ IEMs.


Let me start by getting straight to the point, the ZEX sound pretty darn good for a set of 20€ IEMs. There are more and more options in this price bracket lately, some of which are very decent IEMs that would make plenty of people happy, and I think that the ZEX should be put straight into the decent category without a doubt. They do have a few issues that I will comment on shortly but these IEMs are a set that are impressive upon first listen.

I say first listen because my first impressions were “wow, these have a lot of bass yet sound very clear!” As I have spent more time with them, there have been a few things that have stood out, making them still impressive but remind me that these are not perfect.

The sound signature is very much the typical KZ “V” shape found on the majority of their IEMs, with few exceptions. Over time, KZ has stuck with a similar tuning on most of their set and just achieved it in different ways, with different driver configurations, some working better than others. 

In the case of the ZEX, KZ are using a single Dual Magnetic Dynamic Unit and what they call a Low Voltage Electrostatic Unit. An electrostat is not something found on many IEMs, even if it is not exactly an electrostat, and it does seem to work in favour of these specific IEMs.

I am going to get into the specific frequency ranges and usual steps in just a second but first let me make a note on tips. I have used the included tips (which I wasn’t overly keen on), foam tips (that made them a little dull), Final Audio Tips (which make them more impressive but show a bit of harshness that I am about to comment on) and also Xelastic tips (which fix the harshness but again dull down the clarity a little too much for me). So, my thoughts are based on using the Final Audio tips, tips that do enhance the bass and retain the clarity that I feel these are good at.

Starting with subbass, these have plenty of it. If you are looking for rumble in the low end, the ZEX deliver and manage to do so without losing control too much. As I have stated on many occasions, I am not one for elevated bass unless I am specifically in the mood, well, the ZEX are good candidates for when I am in the mood. “Chameleon” can not be said to be lacking anything at the lowest frequencies and while it is not the most controlled I have ever heard it, it is certainly good enough to be enjoyable. “Nara” is also a very good example of the fullness that the ZEX have all the way down to the lowest notes. Let’s just say that my hearing rolls off before the IEMs seem to.

In the mid and higher bass regions, the bass is still very present and is also clear and articulate. Listening to things like “Forgot About Dre”, where the bass line moves around between 50Hz and 100Hz, it stays present without anything seeming out of place. I listened to quite a bit of Hip Hop and EDM, enjoying the low end presentation of most of it. Moving to things that are less electronically focused, such as “Give Me One Reason” by Tracy Chapman, the bass is a little more elevated than I would choose but does a decent job of staying out of the way of the rest of the frequencies. With “Black Muse” by Prince, I did find that I wanted to dial it down a bit though but still listenable.

And I think that is where KZ have made a decent job of these IEMs. I don’t know where the crossover to the electrostat happens but the ZEX manage to keep mids and highs clear and present, even when the low end is boosted. 

There is a dip in the mids as I mentioned, but the dip is not overly done, or at least the climb up at the end of the mids is enough to make sure vocals and mid centric instruments are present. I was actually very surprised at how detailed and clear these can be in the higher end of the mids and lower treble frequencies. Even for my typical vocal and acoustic instrument focused tracks, they do a good job of keeping everything clear and well presented.

The negative side, there is always a negative side, is that sometimes vocals and other parts of the higher mids can come across as harsh. They are actually not sibilant, at least they don’t add sibilance, but certain parts can be a little brutal at times. This is not all the time, just on occasions, but that can actually be worse at times, as EQ (or tip changes) to remove these harsh appearances seem to dull down the overall signature in general, becoming a little too blunt for my tastes.

Don’t get me wrong, I still feel that these are excellent value for their price, and would still be good value at a much higher price, but those peaks do take the enjoyment away now and again. 

As far as soundstage, well, we are back in the average camp here. They are not bad but are nothing worth noting in this regard. Image placement is also acceptable, maybe a little over average, but again nothing out of this world. 


I think the last set of KZ IEMs I reviewed were the ZAX, a more classic hybrid set up from KZ, and I must say that these are more impressive than the ZAX. By this I don’t mean they are better, I mean that they are more impressive in what they can do. I think that I can dial the ZAX more towards my tastes with my usual selection of music (not just the stuff on my test list) but they are not IEMs that I usually reach for, I have others that I prefer much more.

However, the ZEX are sort of a “Here, take that!” set of IEMs. I was literally surprised when I first heard them and I still am when I pick them up after listening to other stuff, especially with hip hop and EDM.

I would not put them at the top of my recommended list for my personal tastes but I certainly think they are worth (more than) their price. I would have no problem recommending them to people who want to party inside their head. They sort of remind me of some car systems that people spend a lot of time (and money) perfecting to get that Saturday night parking lot EDM party set up, and these only cost 20€.

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