100+ Head-Fier
Pros: Perhaps the best KZ tuning thus far with less aggression and more balance across the ranges
- Really good imaging
- Great instrument separation
Cons: Questionable design and poor comfort
- Awful stock cable
- Still too hot in the upper mids and lower treble
- Sub-bass roll-off
It’s difficult to keep track of how many IEMs KZ have launched in a month.

Or so was the case before the launch of the KZ ZSX — dubbed as the “Terminator” by KZ themselves. Whether it terminates the competition, or merely the rest of the KZ lineup is the question.

This is the first time I will formally review a KZ IEM, as apart from the KZ ATE all their IEMs since then have been various forms of meh. They are not bad in terms of specs, as KZ seems to be very intent on winning the driver-count war (as useless as the megapixel war in smartphones). While the sound didn’t noticeably improve for the most part, their marketing team had a field day with the increased driver count, and so with the ZSX we’ve got 12 drivers (!), though that’s basically 6 drivers on one side…

So yes, none of it makes sense. Let’s just get on with the review.

[ You can read a better formatted version of this review on my blog. ]


Note: the ratings given will be subjective to the price tier. Definitely the expectations from a $15 IEM won’t be the same as a $150 one, and that’s the approach taken while assigning scores. I bought the IEMs with my own funds, still, Disclaimer

Sources used: LG G7, Questyle QP1R

Build: The build quality is a mixed bag with the ZSX. The face-plate is something that I find nicely finished, even though it tends to retain smudges. The issue is the resin shell as it looks really cheap and tacky. While I’m glad that KZ got rid of stupid texts on the IEM shells, the poor finish on the shells don’t do much in hiding their budget roots. The metal nozzle is a nice touch, and the 2-pin connector itself is pretty standard. Inside, there are six drivers — one super-high BA, two mid-high dual-BA (four in total), and a solitary 10mm dynamic driver (presumably responsible for the bass). Do note that all those BA drivers are Bellsing drivers (or similar). No Knowles/Sonion BA here. Also, there seems to be no physical cross-overs in sight, so it’s basically a mix of some slots for the drivers and coaxial placement (for the super-high BA).
Another subjective observation: this is perhaps one of the ugliest IEMs I’ve ever used, period. The design is just… too random. Not that they picked this particular shape due to comfort (more on that later), rather it seems like this is how they could fit all six of those drivers. It just doesn’t seem very appealing to me, and while it is a subjective statement, it does lack of the finesse of some other IEMs at this range.


Accessories: Ah, KZ and their accessories, or the lack thereof. $50 is not necessarily a premium price, but to only have a terrible cable in the packaging and no carrying case — it’s not gonna cut in 2019. KZ has always tried to get away with as poor a cable as possible, and that trend continues even now. Disappointing. Ah well, at least the eartips are decent.


Comfort: Due to the random protrusions from the inner-side of the IEM, these are not comfortable at all. I had to yank them out of my ears after a half hour listening session as they induced some serious pain. This is the first time I’ve had to resort to such measures on an IEM (it only happened once before with the M50X aka torture-cans). The comfort that these IEMs provide are questionable at best and downright unusable at worst. Also, they have poor isolation, so best of luck during your commutes.


Now, on to the sound:

Bass: KZ ZSX has a slightly emphasized mid-bass, and rolled-off sub-bass. The sub-bass roll-off is evident in the lack of rumble. The one odd thing about the bass response is that it sounds somewhat disconnected from the rest of the sound. That is probably down to the lack of a physical cross-over, but there’s no point in speculating much over it. The other, more pressing issue with the bass response is that it lacks the “texture” of other good dynamic drivers. While KZ has used a newer (and apparently better than the previous gen driver) dynamic driver, the texture of the bass is completely lost in the mix. Every bass note sounds the same, there’s no subtle shift in tones. It would be excusable for a $50 IEM a few years back, but times have changed.

Mids: Midrange has a lower-mid dip that’s not too evident from the graphs but once you start listening to them, this dip stands out. On some lower-pitched male vocals this leads to sense of “compressed” sounding vocals. Case in point: Colin Hay’s I Just Don’t Think I’ll Get Over You has a deep, baritone-like lead vocals with subtle acoustic strums along the way. The subtlety of Hay’s voice is completely lost on the ZSX, as it sounds overly compressed.
On the other end of the spectrum, female vocals can often sound too energetic, depending on the track. Donna Burke’s rendition of Glassy Sky exhibits this issue, and sounds overly bright to my ears. There are also subtle hints of sibilance, though nothing that distracts too much.
String instruments sound fine for the most part, and due to pretty good instrument separation, it might sound really impressive at first listen. It’s only when you start listening to more and varied tracks do the issues crop up. Overall, it’s a pretty decent sounding midrange that falls short of budget-perfection.

Treble: The treble is where things start to get troublesome as the infamous BA-timbre is on full-display here. The cymbal crashes sound too thin and sharp, as the bump around 7–8KHz is a bit overcooked, and due to the placement of the BA driver inside the nozzle itself — it’s all too distracting at times. For example, Breaking Benjamin’s The Diary of Jane has a lot of cymbal hits in the background, all of which sound unnaturally thin and splashy on the ZSX.
The presence region (~5–6KHz) also has a bump that makes everything sound intense, and I personally cannot listen to the ZSX for long due to this overall bright treble. Coupled with the comfort issues — this is an IEM I find myself taking a break with more often than not, and that’s a shame, as on slower and less heavy tracks the treble is actually rather fine. On heavier genres though, this might be too bright for its own good.


Soundstage: The soundstage is average. Nothing to write home about here. It doesn’t sound claustrophobic, so there’s that.

Imaging: Usually multi-driver IEMs get an advantage in imaging as the literally separate position of various drivers often grant better localization of certain instruments. It is a similar case with the ZSX as instrument placement is mostly well done.
One strange thing about ZSX’s imaging is that it does the “corner” imaging well, i.e. instruments on top-left/top-right will often sound where they should, but when it comes to panning across the stage, ZSX struggles. On tracks like Godsmack’s Straight Out of Line, the snare hits/guitar distortions often start from left/right and then finishes on the other end. ZSX has this tendency to abruptly shift from left to right instead of a smooth, continuous motion. This might not be too much an issue for many people but certain other IEMs get this correct, so it had to be mentioned.

Bang-for-buck: These are not the absolute-best-bargain-deal. They are a decent set of IEMs that might fit your needs, but you can most likely find something else just as good, if not better, at or around the price point. Also, the accessory set is a huge bummer.
Still, these are not necessarily overpriced, so there’s that.


Source and Amping: Make sure that your output device has less than 1–1.5ohm of impedance, as otherwise the ZSX will exhibit some odd behaviors. This is an old issue with many multi-BA IEMs, so nothing unique with the ZSX. Fortunately enough, most of the mobile phones/dongles have really low output-impedance and due to the very high sensitivity of the ZSX they will run just fine on those devices.


Select Comparisons

vs Tin HiFi T3: Tin T3 has recently been superceded by the T4, but Tin HiFi is still selling them around the same price as the ZSX. For one, the T3 is built much better, and the accessories are of significantly higher quality. The cable especially is on another level.
In terms of build quality, T3 has the upper hand, and the same goes for comfort.
As for the all-important sound quality, T3 has a leaner presentation with much thinner bass notes that lack even more sub-bass impact. The mid-range is also noticeably leaner on the T3. Treble, however, is smoother and better defined for my tastes on the T3. If you need a more energetic, on-your-face sound then ZSX is the way to go. Or if you prefer a more analytical signature, T3 might be the better option.

vs BLON BL-03: This is the comparison that everyone wants, so let’s just get into it. Both of the IEMs have terrible accessories, so it’s a tie. BLON however requires that you get a pair of 3rd party eartips, so there’s that added cost (though even with a pair of Spinfits it costs less than the ZSX retail).
Then, there is comfort, and with proper tips the BL-03 is more comfortable. Both have similarly poor isolation so it’s a tie.
Sound signature is where they are very different. BLON BL-03 focuses on a more measured approach and attempts to strike a beautiful balance between the bass, mids and highs. It largely succeeds as well, since you get a really punchy bass that doesn’t bleed into the mids, fantastic vocal rendition (esp female) and a smooth-yet-sparkly treble that delivers some air and shimmer around the upper-treble.
ZSX is all about an up-front signature. This works well with genres like Rock where distortion guitars and raspy vocals take center-stage. However, with heavier genres like Metal the bright treble might be a bit too hot to handle. Also the bass is definitely a step down from the BLONs.
If I had to pick between one of them — it will be the BLON BL-03 hands down, but that’s just me.



“Don’t forget, the original intention of using earphone is to enjoy music.”
That’s what KZ has printed inside the ZSX box.

Well, the ZSX will indeed allow you to enjoy your music, at least some of it. This one is, in my opinion, the best KZ IEM to date. However, the IEM world is not a bubble, as newcomers like BLON has completely redefined the budget IEM range and KZ is already on the back-foot. They have their driver-count marketing trick, but it won’t work for long.

KZ has been manufacturing IEMs for over 5 years and they are wildly successful. Still, I don’t see the ambition there. They are mostly about pushing volumes and not pushing the very definition of budget IEMs, which is a darn shame as their original ATE was one of those budget IEMs that sounded like it costs quite a lot more.

KZ is finally heading in the right direction with the ZSX, as this one is tuned a lot better than their previous stuff. However, pressing issues like poor QC control and a total lack of design awareness still exist.

As for if you should buy the ZSX — try before you buy, and try it for a while. If the comfort is alright and that 5/6KHz peak is not an issue then you can definitely give it a shot. It doesn’t sound terrible, is mostly as coherent as you can expect a $50 IEM to be, and has some nice instrument separation to boot.

However, it won’t be my first recommendation, or the second, not at that price. Too bad.

You can check the current prices here (non-affiliated link).

Test tracks (as YouTube playlist, often updated):
Dr Rez
Dr Rez
Great review. Dont listen to Broken1981...he clearly does not know how to read and think at the same time.

I agree fully about the Blons. Have you given the bl05 or.bl01 a try yet?
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I have already reviewed the BL-05 and I am not a big fan of it. However, the BL-05S (updated version of BL-05, unique green color shells) are my favorite BLON till date. Very technically proficient while facilitating long-term listen. One of the best under $50 IMO.

The BL-01 didn't seem like an upgrade over the BL-05S to me and the midrange lost some of the analogue smoothness of the BL-03. I will likely not review it since it's mostly a sidegrade for me.
Dr Rez
Dr Rez
Why does the bl05s have to be such an ugly horrid color lol....Id love to get it...if only it was normal looking.


Headphoneus Supremus
Pros: Best KZ Tuning to date
Good treble resolution
Cons: Uncomfortable to wear due to large size
Bass is lacking any sort of resolution

The Terminator is here. The latest KZ ZSX, dubbed, The Terminator, is a 6-driver hybrid in-ear monitor earphone with a single dynamic driver and 5 balanced armature drivers feeding it through a rather large shell. The new shell design has a silver triangular look to it that looks a little strange to me, but feels well made at the same time.

The fit itself is a bit of a problem. It’s larger than other IEMs I’ve tried outside of say the Campfire Solaris and my current daily driver, the qdc Anole VX, and the highly praised Sony IER-Z1R, but it’s in the same realm as those in terms of size. The main issue for me is that the angle of the nozzle spout is not in the most optimal direction for my ear and that its not only long, but also has a large diameter. Now, long nozzle shafts don’t bother me, as something like the Moondrop Kanas Pro is really comfortable for me, and so are things like the Campfire Andromeda Gold and IO. Large diameter IEMs are also not a problem, but the combination of the two, with the angle choice, makes it a tough fit for me, and limits my time wearing these to shorter spurts – much like the issues I faced with the Campfire Solaris previously.

Judgement Day Sound

The ZSX has a full-bodied sound that isn’t too far away from some of my favorite top of the line tunings like the ones presented by Solaris and the IER-Z1R – which both present a warm, balanced sound with treble energy and thick lower mids. Of course, the significantly cheaper KZ ZSX is nowhere near the other two when it comes to things like resolution, speed, imaging, and detail. In fact, its quite a step back, but still, the ZSX is impressive for a product made by KZ and of a $50 price tag.

The bass is punchy and elevated, however not bolstered enough to be considered a super bassy IEM. It has good subbass and a downward slope to the mids that has gives impact to drum kicks and has a mild slam to it – more so than the Solaris did. The bass resolution is pretty mediocre though, and the speed of the driver is a tad slow, leaving bass notes to hang out a little longer than I would like. I do tend to prefer nimble, quick, and agile bass responses that provide plenty of detail and textured layering, and the ZSX sounds more like bass noise than bass resolution.

The mid-range is warm, rich and full of body. I never found the mid-range to be too recessed – in fact, I actually like how it’s presented. Male vocals have girth to it, and female vocals do shine and are forward with a response curve that starts sloping upward at 1KHz and almost follows a Diffuse Field type curve until the about 3.5KHz where it has a small drop. This does help it from being too forward and too harsh for me, and gives it a little bit more breathing room from possible congestion.

There is a slight bit of harshness due to an elevated treble peak that can make things a little spicy at times. I never found it overly bright and fatiguing, but just note that it’s not as smooth sounding in that area as say the Solaris or the VX, which I really both enjoy it’s tuning. It’s more along the lines of the Sony IER-Z1R, with its slightly bright tuning in that area. Again, I’m just using some of these known IEMs as a base line and I am not saying the ZSX is of the same caliber. It’s just a similar overall tuning from a high-level overview shot of the IEM’s sound.

I found the ZSX sounding best with rock and country music. The elevated bass that isn’t over done gives drums and bass guitars the needed bump, while the punchiness gives the kick needed to steer rock songs, while the tuning of the upper-midrange and treble gives clarity to guitars and cymbals. It works well for these popular genres.


The ZSX is a nice choice for a budget IEM, and easily my favorite of one from KZ. It actually is very similar in tuning to the ZS10 Pro, my previous favorite, but downplays the treble a bit, which makes this one not as harsh and fatiguing as the ZS10 Pro was.

The fit, however, is large and should be something to look out for. It’s not going to fit with some people’s ears, including mine, and that could make this a non-starter to begin with. I do have smaller ear canals than a lot of people, and typically wear small ear tips, so the larger nozzle shape and angle really don’t do me any favors here.

So, if you can deal with that shortcoming and your budget was around $50, and you like this type of tuning, this could be a decent set to look out for. It falls in-line with tuning of some of my favorites, and that’s half the battle for me, and that’s why this was instantly one that I enjoyed when I first heard it.
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New Head-Fier
Pros: Well rounded and mature sound
Nice extended treble without being annoying or harsh
Never tedious for extended listening
Cons: Still not a big fan of the KZ braided cable
KZ just keeps turning out top flight earbuds at an outstanding rate and it is getting hard to keep up. It gets to the point that you are going to be guaranteed a certain listenable quality piece for $50 or less, and it's just a question of your preference in tuning and comfort levels. The new KZ ZSX is a perfect example of this phenomenon. This gear bills itself as a 6 driver per side IEM with a newly developed higher frequency balanced armature driver and, like others in this lineup, it is quality made metal face plate and very attractive, although perhaps a little bulky for some. I am not a huge fan of the braided cable that now seems standards on the KZ line, but at least this model had the more comfortable and springy ear wrap at the attachment points, which is a must for me. I can wear these without discomfort despite their weight.

My impression on sound is that this KZ ZSX is a much more mature and less in your face presentation that some of the previous KZs I own, like the ZS10Pro, which is a similarly styled over the ear unit. The ZSX puts the music together is a more holistic way and, after some break in period, I noticed some nuances in male vocals that I hadn't heard in some of my earlier KZ models. When I upgraded to a better source unit, or popped an Audioquest Dragonfly on the iphone, the quality and smooth presentation became more obvious. The sub bass in substantial but well controlled, The mids are clean, nothing spectacular, but the treble stands out as detailed with a nice reach and a touch of sparkle but not in an annoying way. It is simply about as listenable as you are going to get at this price point and a very attractive package as well. I will follow up later after I spend more time with the ZSX.


New Head-Fier
Pros: Clean and deep bass
Good sound
Solid build quality
Cons: Unique shape
The midrange is not as good as the highs and bass
T3A7609F3-E003-4AD9-91EE-6EF9B1F368BB.jpeg D69B7EA8-8B1E-4640-9637-F1F09F9B1E53.jpeg F35A8923-FABC-42B4-BA90-216D0B7BD334.jpeg 578006B0-2F29-42FA-A839-6CF102678DD7.jpeg 8B2C0245-834A-4C7F-BDDB-77F37E3CE785.jpeg 20105402-1B27-495F-841F-AB004A95136A.jpeg DF876B0F-660F-4936-B909-B5B68426E458.jpeg 41046CC8-9B5B-4840-9255-EA6E3B2B4179.jpeg 3A7609F3-E003-4AD9-91EE-6EF9B1F368BB.jpeg Greetings! Today we are checking out the Kz ZSX which was provided by EE Audio store in aliexpress. This is a hybrid 6 driver item! Hope you enjoy the review!

This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.
If you are intrested, the link is down below:


    • Driver: 5BA+1DD
    • Impedance: 24ohm
    • Sensitivity: 111dB
    • Frequency Response: 7Hz-40kHz
    • Length:125cm
    • Plug Type: 3.5mm Plug

Build quality

KZ appears to have hooked onto a typical topic for their shell
structures recently as well, "When you're onto something worth being thankful for, stay with it." So, by and by, we see a slight variation of what is by all accounts the new all-inclusive KZ shells. We get an aluminium faceplate with a straightforward acrylic shell. The faceplate has a cutting edge look with a progression of V-formed edges and pointed triangular shape. "12 Hybrid" is imprinted on the face, advising us that this financial limit IEM has a high driver tally (despite the fact that there are just 6 drivers for each side). No doubt there are 3 well-known shading decisions in humankind's future and those are the accessible decisions for your shade of ZSX shell, which incorporate dark, cyan and purple.


For my medium measured ears, the ZSX is a decent match however it might be unbalanced for those with littler ears. It's greater than the ZS10 Pro and projects out from the ears more. The spouts arrive at more profound which could be fortunate or unfortunate, contingent upon your ears and favoured ear tips. Actually, I can wear these throughout the day no stresses by any stretch of the imagination.

Commotion detachment is quite great and these are appropriate for loud situations and open vehicle. Clamour hole is genuinely insignificant as well, so you needn't stress over that.

The ZSX has a vivacious and forthright introduction. Supported bass, drawing in mids and energetic treble are portrayals that rung a bell. It performs well beyond what I typically expect for a sub $100 IEM. Lucidity? Got it. Tone? Got it. Instrument division – without a doubt.

Here's the place things are extremely fun. The new 10mm driver is punchy and tight. It remains clean, doesn't overwhelm different frequencies and keeps up an OK by and large parity.

Low bass reaction is exceptionally better than average and the mid-bass is forward in the blend and, subsequently is extremely captivating. Shake, EDM or Hip-Hop fans will discover a great deal to like with the ZSX. It hits hard however with control and artfulness.

The ZSX bass resembles a sand trap. At the point when your initial phase in it feels ordinary. At that point, before you realize it you're tapping your feet and overwhelmed with it. I'm certain even the Avengers' Mr Fantastic would be intrigued by the compass of the ZSX's low end.

A sensibly quick assault gives the mid-bass some smartness and surface however the long rot is the place the weight and authority originate from. Regardless of its plenteous circumference, the bass doesn't feel drowsy and keeps up a decent pace.

The midrange is consistently the weakest piece of the house KZ sound. With the ZSX the midrange is sensibly forward with average body yet simply doesn't convey to a similar degree as the upper and lower frequencies. There is almost no treble or bass seep over, so the midrange, while to some degree recessed in the blend, remains clear and point by point.

Voices run over common and female vocals appear to sparkle more than male. Truly, the midrange is fine, it simply doesn't have an incredible 'amazing' factor as the bass and treble

ZSX has a genuinely nonpartisan midrange until it begins to ascend in the upper mids. Normally, it gets some glow from the bass however the lower midrange is generally uncoloured and genuinely lean. There is a lift in the upper mids that includes a little brilliance and assault to guitars and percussion.

Male vocals are a touch dry and could utilize some additional glow to sound increasingly normal yet female vocals are fresh and dynamic. The leanness of the midrange notes makes for a nitty-gritty introduction and great vocal enunciation.


For me, the treble has improved the most when contrasted with the ZS10 Pro. There's no indication of the standard KZ steely treble timbre. It never again seems like somebody swinging a sledge in the kitchen sink.

By and large, it's a fresh and itemized treble with great tone and great augmentation. It's not sibilant or cruel and the 10kHz pinnacle includes air and lucidity in with the general mish-mash. This is the sort of treble that KZ ought to accomplish all the more regularly.

There is a wealth of splendid detail accessible. The ZSX treble is very broadened and to some degree raised, yet the decent armatures stay clear and sensibly free of sibilance or weariness.

The treble is an extraordinary antithesis to such tight bass on the opposite end. By and large the sound mark stays adjusted yet pleasantly broadened (both high and low). Music is introduced neatly, obviously and intensely.

The ZSX is an extremely enthusiastic sounding IEM; super-captivating and fun.


The ZSX makes a normal stage with more width than profundity. The vocals are situated toward the back of the stage while instruments are set nearer to the front. There isn't much in the method for layering but since of the better than expected instrument partition, the stage feels genuinely open. Imaging and positional prompts are strong for something in this value go.

I truly like the ZS10 Pro, so the undeniable inquiry is the 6-driver (per IEM) ZSX an overhaul over the 5-driver ZS10 Pro?

I lean toward the littler size and in general style of the ZS10 Pro, however it's a nearby thing. Both fit my ears easily and look very great.

Sound quality is additionally very comparable, yet I accept the gesture needs to go to the new challenger. The ZSX highs are a piece more clear and increasingly definite. Generally the sound is a smidgen increasingly forward and locks in. Bass, while maybe somewhat less profound than the ZS10 Pro, is better controlled and cleaner on the ZSX.

It is not necessarily the case that the ZS10 Pro isn't even now an incredible spending plan IEM. (It is!) The ZS10 Pro and the ZSX are unbelievably comparative items, at for all intents and purposes a similar value point, and discharged by a similar maker inside a couple of months. No big surprise online discussions are brimming with people asking which one they should purchase.

Practice is without a doubt making ideal for KZ. They keep on discharging a surge of new models, and it can feel like each new IEM is a beta test for the following one, yet they truly improve. On the off chance that you tuned in to before models and kept in touch with them off, this is the ideal opportunity to give KZ another possibility.

Keep in mind, this is another spending limit IEM model around $50. KZ as of late explored different avenues regarding a more significant expense point with the AS16, however at $100+, the standard heap of adornments, construct, and the sound quality wasn't exactly as convincing. With the ZS10 Pro and now the ZSX, KZ has made progress to (*ahem*) end the challenge at this lower (entirely moderate) value point


Pros: - great clarity and separation
- not as bright or harsh as some older models
Cons: - recessed lower mids
- price
New day, ne KZ model. :) I'll try to keep it short and to the point here.

BUILD QUALITY - they look and feel built like a tank, I didn't notice any QC issues. These are the bulkiest KZs I head so far, bulkier even than ZS10, and that did create some small comfort issues for me when I tried to insert them deeper into my ear canal to make a more secure fit.

SOUND QUALITY - is very nice. Overall clarity and separation is top-notch while sound signature is still V-shaped with recessed lower mids. Anyway they do sound fuller and juicier than ZS10 and I definitely appreciate that. Overall I feel these are the best sounding KZs I've tried so far. It's just that I can get this same overall sound quality with even better frequency balance and much fuller sounding vocals from the likes of TIN Audio T2 and **** ****. Moreover both of these cost less too, hence 3.5 stars for ZSX. But if you prefer V-shaped sound with emphasized upper register - I guess there's nothing really wrong with choosing them.

I made a video comparison with T2s


Headphoneus Supremus
Pros: Well tuned signature with good mids and less treble than we are used to for KZ.
Cons: Treble still a bit grainy and can get harsh occasionally, cable still sucks.
disclaimer: Due to a miscue in communication, I received the KZ ZSX from both HifiGo, and Linsoul Audio. At time of this writing, both vendors have the same pricing for the ZSX and a variety of other models available. I recommend checking out both as I have been well pleased with my purchases from both organizations.

These can be purchased directly from hifigo for those interested.

Unboxing / Packaging:

The ZSX comes in a new style box for KZ, gone is the white slip cover with the graphics on the front, replaced with a book fold box in matte black with a KZ logo in satin black. Its a nice understated look and gives the feel that what is inside is of higher quality than their typical packaging. Opening the cover and the earpieces are revealed nestled in a foam block with a placard similar to that which came with the Zs7. The cable and tips (SML Stars) are hiding under the foam. No case or other accessories are provided.

KZ-ZSX-box-front.JPG KZ-ZSX-box-open2.JPG KZ-ZSX-box-inner3.JPG KZ-ZSX-kit2.JPG


Shells are 3 parts with a metal face plate, a plastic inner shell (available in multiple colors), and a metal nozzle. The shape is a departure from previous models and looks a bit like an art deco, Zs10 Pro. In photos they look like a triangle that sits tip down, when worn that tip is to the front while the short side of the triangle sits against the rear of the ear. These are more comfortable than I anticipated when first looking at them. They are a mid-sized iem and the shape does a lot to make them feel smaller than they actually are. Nozzles exit the shell with an upward rake and allow for fairly deep insertion which makes isolation reasonably good. A single vent sits directly over the dynamic driver on the inner shell. For those looking at both, the shell shape of the ZSX is more comfortable than that of the CCA c10 as the C10 doesn’t have any of the shaping to the inner shell that the ZSX does. I have tried to get a few photos to show the differences in the comparison section.

KZ-ZSX-back2.JPG KZ-ZSX-inside.JPG KZ-ZSX-nozzle.JPG KZ-ZSX-nozzle2.JPG KZ-ZSX-pair1.JPG KZ-ZSX-shell.JPG KZ-ZSX-side2.JPG KZ-ZSX-top-bi-pin.JPG


The ZSX is a 6 driver per side design using a single 10mm dynamic driver to provide low end grunt, four DWEK midrange balanced armatures to bring the mids to life, and a single 30095 balanced armature to give the highs a voice. This is a departure from earlier models that doubled down on the treble and often showed quite a spike as a result. Nominal impedance is listed as 24Ω with a sensitivity of 111dB/mW and based on how easy I found the ZSX to drive, I have no reason to doubt those numbers.


This is the biggest let down of the ZSX, the same brown cable KZ has been using for everything with no correction for the ultra-low on cable splitter and no chin slider. Luckily the hooded-bi-pin style connector is now popular enough that many replacement options are available. I promptly replaced the stock cable with an upgrade cable from Nicehck designed for the Nx7 and it worked perfectly and remedied some of the issues I have with the stock cable.

KZ-ZSX-jack2.JPG KZ-ZSX-mic.JPG KZ-ZSX-remote.JPG KZ-ZSX-splitter.JPG KZ-ZSX-bi-pin.JPG


I found the ZSX to be less tip sensitive than many models and found the provided mid-sized tips worked fine for me so I stuck with the starlines for testing.



The ZSX has good sub-bass when called upon with roll-off only becoming evident below 40Hz. Mid-bass has slightly less emphasis than the sub-bass but still provides good thump. One thing I did notice right away is the bass has considerably faster attack than decay which gives the bass an interesting mix of thickness and texture. While I would prefer the bass decay was a hair faster, it doesn’t get gummy or sluggish, it just fills the space to give a heavier feel than faster decay would. The attack gives the kick drum a nice snap on the initial hit and keeps the bass from sounding less defined. Overall, not a ton of detail in the bass, but a nice thick presentation that won’t leave the user wanting for bass quantity.


There is some mid-bass bleed that colors the lower mids, but it isn’t overstated and brings some warmth to what might otherwise be a bit dry presentation by the balanced armatures. As you move up, the mids climb forward giving female vocals a bit more presence than their male counterparts. This also gives higher range vocals a bit more body than their lower counterparts with the lower voices sounding a bit dry and slightly lean by comparison. The upper mid push does a good job of bringing electric guitar to the front, but isn’t to my liking when listening to strings as it brings them too far forward at times.


Those expecting me to state that the ZSX has the stereotypical KZ treble will be disappointed to hear that the ZSX has replaced KZ’s normal splashy, harsh treble with a much more polite version of itself. Lower treble is still a bit forward, but at least it doesn’t smack you in the face with a brick like the Zs6. As treble moves up we see a distinct step back at about 8kHz and a peak between 10 and 11khz that brings back some top end air and sparkle without jumping way out in front of the rest of the signature. Treble detail is only average, but clarity is good and extension is better than expected.

Soundstage / Imaging:

This is where the ZSX falls down. Soundstage is only average for class with considerably more width than depth and only minimal height. Instrument separation is above average and this probably saves the ZSX as it keeps the sound fairly clean without a lot of overlapped instrumentation despite the stage size. Imaging is acceptable for something in the <50 USD price range, but not anything special and I did find a tendency for guitars to step in front of vocals, particularly when vocals were in the lower registers.


CCA C12 – these two are siblings with a lot of commonality. Cables are the same, shells vary in dimensions but not in materials, and drivers are the same between the two. The ZSX is tuned with a bit more warmth and a bit more lower mids while the CCA has a bit less grain to the treble but a bit more dip in the mids. Both are more similar than not in sound signature with differences being a matter of degrees. I prefer the CCA version slightly as I think the treble is a bit cleaner, but those looking for a bit livelier sound will probably prefer the ZSX.

ZS10 Pro – Another cousin to the ZSX with one less BA and a different tuning. Shell on the Zs10 pro is slightly smaller which will be an advantage to those with small ears. Sound wise, these two are also very close but the ZSX bass is slightly better extended and slightly more pronounced so it comes off as thicker without sounding clouded. Mids are too close to call on these two as if there are differences in detail level or signature they are beyond the scope of what I can hear. Treble extension and control are both good on both models but slightly better on the ZSX in my experience. Honestly, if you own one of these two, you can probably skip the other as the degree of difference is not earth shattering.

Thoughts / Conclusion:

The seemingly never ending stream of KZ models marches on with no slow down in sight. At this point, having reviewed a lot of KZ products that are more similar than not, I can honestly say I would much prefer that they slow down and choose 2 or 3 of the best models to really work on developing and improving rather than continuing to release a stream of more of the same. I ended up with two ZSX due to a communication error and with already owning the Zs10 Pro, I realistically have 3 of the same thing. Yes they are nicer than one would have expected for the price, but they are not a great departure from previous efforts. Tuning has improved greatly on the KZs of late (for the most part) but the bass still lacks definition and the upper end still has a tendency to get strident on occasion compared to top end models. Overall, the ZSX is another evolutionary step but a very small one. If you have an interest in the ZSX, it can be purchased directly from Linsoul or from their Amazon Store here.


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Pros: Fun, enjoyable tuning
Good subbass extension
Upper mids/lower treble forward presentation
No sibilance or treble peaks
Cons: Uncomfortable fit after a while
One-notedness to the bass
BA timbre

This is a review of the KZ ZSX, a $50 KZ IEM that contains 5 BA and 1 DD. I got this as a review unit from Linsoul. If you're interested in it after reading this review, you can grab one here.

Overall Sound Signature: A very enjoyable and unapologetically energetic V-shaped IEM that is unfortunately marred by BA timbre.

Bass: The bass on the ZSX is elevated and at the forefront of its presentation. The DD is quick and provides a deep punchy bass response with great subbass extension. Decay is quick and the ZSX never gets boomy nor bloomy. However, like the many other KZ models, it suffers from a one-notedness to the sound quality, lacking the nuance in note timbre found in higher quality DD's (or even its budget friend the BLON BL-03). Midbass response is likewise pushed forward and the tightness of the DD helps bring out note clarity in quick bass lines. There isn't much bass bloat or muddiness, with the DD having a distinction from the BAs of the mids.

Mids: The lower mids have a slight incoherency issue as the midbass transitions into the lower mids and the BAs take over from the DD. At times, you can hear when notes are caught in that midpoint where the note timbre sounds distinctly off. Although the lower mids are elevated as part of the tuning, the ZSX doesn't sound too warm thanks to its pronounced upper mids. Vocals are forward and clear with surprisingly good vocal separation. Electric guitars are crunchy without lacking body. Once again, however, the BA timbre does shine through and doesn't sound fully natural.

Treble: As a V-shaped IEM, the ZSX is a little odd in that it has lower treble in spades but quickly drops off when it comes to the higher registers. The lower treble on the ZSX is crisp and distinct, especially when it comes to the cymbals/hats with nice definition upon the initial attack of the lower notes. However, sustained playing on the cymbals/hats at higher frequencies gets relegated to the background almost as a messy noise since the ZSX simply doesn't emphasize the frequencies there. The upside to this is that the ZSX doesn't have any sibilance in the vocals for me, is not peaky, and is not fatiguing to listen to. That said, it's not as if the ZSX doesn't have upper treble, it's just much less pronounced in comparison to its forward upper mids/lower treble.

Staging and Imaging: Like many other KZ models, the staging and imaging are that of traditional IEMs. That is to say, average at best. Nothing to complain about, but nothing great either.

Resolution and Separation: The resolution of the ZSX is definitely above that of similarly priced IEMs thanks in part to speedy BAs and the lower treble emphasis, making it feel clean compared to the smeariness of other budget models. As mentioned earlier, separation is great for vocals and other instruments with a distinct upper mid focus but can get fuzzy at crossover points like the lower mids or at in the treble.

Build and Fit: KZ seemingly has evolved their products to have a very standard style nowadays, and the ZSX is no different. It sports an over-ear design with a largish ergonomic shell design that seals easily for me. However, the issue I have with the ZSX is that it is relatively shallow fit while having a large nozzle that is uncomfortable to wear for longer periods of time. The cable and included tips are standard KZ, so nothing special there.

Should you buy it?: For $50, I highly recommend it. I think the KZ ZSX is a great value with a fun tuning that fits almost everyone. I very much enjoyed listening to the ZSX, something that I can't say for any of the past KZ products I've had to listen to before. It's simply a solid V-shaped IEM that you can't go wrong with, either for yourself or as a gift. While it may not be as technically proficient as the BLON BL-03, I do personally prefer the ZSX's more energetic tuning, especially for rock. Just watch out if you really care about bass quality and a more natural sound than what BAs provide.


500+ Head-Fier
Pros: engaging tuning, solid technical performance for price point
Cons: tangle-prone cable with no chin slider, large housings
The KZ KZX is a hybrid in-ear monitor (5BA +1DD ) retailing for around $42 at the time of this review. I purchased the ZSX from the MissAudio Store on Aliexpress for $37.10. I was given a small discount in exchange for a fair and objective review.

This review is also available on my blog: Bedrock Reviews


I have used the KZ ZSX with the following sources:

Windows 10 PC > JDS Labs The Element > KZ ZSX

Pixel 3 > Fiio BTR1K (Bluetooth Apt-X) > KZ ZSX

Windows 10 PC > Fiio BTR1K (USB-DAC) > KZ ZSX

Pixel 3 > Apple USB-C to 3.5mm dongle > KZ ZSX

I have tested these headphones with local FLAC, Spotify Premium, and Amazon Music HD. Visit my page to get an idea of what I listen to.

The KZ ZSX comes in a small rectangular black box with a lid that opens to the left. The box is unmarked apart from the KZ logo printed on the front of the lid. Stickers on the left face of the box indicate the selected mic and color options, as well as KZ’s contact information in Chinese and English. The ZSX comes with a detachable .75mm 2-pin cable, three pairs of KZ Starline-type black silicone eartips (S, M, L), one pair of generic black silicone eartips (M), a user manual, a QC pass chit, and a warranty card. The ZSX does not include a carry bag or case.

The KZ ZSX has a similar design to other recent KZ-affiliated IEMs, with a metal faceplate and a clear inner acrylic body. The acrylic body is diamond-shaped with a rounded-off top corner. The acrylic body has a bulbous protrusion on the top corner, while the nozzle is swept forward from the bottom corner. “KZ-ZSX” and “Left/Right” are printed on the front side of the acrylic body. The total driver count (12) is printed on the faceplate. The nozzles are metal, with a small lip for securing eartips. Each earpiece has two small circular vents on the inner face of the housing. The ZSX has mild driver flex.
The cable is braided copper with clear plastic housings for the 2-pin connections and an L-shaped black rubber housing for the 3.5mm jack. The cable has little-to-no microphonics. The 2-pin connectors use the KZ “type-C” recessed connector. The 2-pin connectors have indented markings to indicate left and right. The cable has pre-formed ear-guides without memory wire. The KZ logo is embossed on the 3.5mm jack housing. There is no chin-adjustment choker. The cable is less tangle-prone than the CCA-C10’s cable, but more tangle-prone than the Tripowin TP10’s cable. There strain-relief above the 3.5mm jack and at all junctures of the Y-split.

The KZ ZSX is intended to be worn cable-up only. The ZSX has a moderate insertion depth and I was able to get a good seal using the stock eartips. Despite my small ears and the size of the housings, I did not experience any issues with comfort. However, other users have noted comfort issues with the bulbous protrusion on the top corner of the acrylic housing. There is negligible sound leakage and isolation is above average.

The KZ ZSX has a temperate V-shaped tuning that is engaging without being exaggerated.

Sub-bass is well-extended. There is more sub-bass than mid-bass, but the mid-bass is elevated enough to give the overall sound signature a sense of heft. The bass has good texture but is not precise. The bass has a fast attack but lingers a hair longer than I would like during fast and complex musical passages. While not bloated, the elevated bass does create some congestion in the lower midrange.

Female vocals are a bit further forward than male vocals. Male vocal intelligibility suffers a little from the congestion created by the elevated bass but the lower midrange has plenty of warmth and body. The overall timbre is passably realistic, but some instruments, like drums, can sound thin. There is enough presence to give distorted electric guitars bite without being fatiguing.

The treble is exciting but can stray into harshness, particularly with poorly recorded music. Cymbal crashes have a satisfying sizzle. There is a good amount of air and moderate sparkle. Resolution and detail retrieval are average. Soundstage and instrument separation are average for a multi-BA hybrid. Imaging is average.

KZ ZSX.jpg
My measurements were conducted with a Dayton iMM-6 microphone using a vinyl tubing coupler and a calibrated USB sound interface. The measurements use a compensation file derived from comparing my raw measurements with Crinacle’s published measurements. The measurements are presented with 1/24th smoothing. There is a resonant peak at 8k. Measurements above 10k are not reliable.


The KZ ZSX can be driven to comfortable listening volumes with a smartphone or dongle. There is noticeable hiss with some sources.


KZ ZSX [$35] vs Blon BL-03 [$30]
ZSX vs BL-03.jpg
The Blon BL-03 uses a single carbon nanotube dynamic driver. It has a more neutral sound signature, with a more restrained bass presentation and a less forward upper midrange and treble response. The BL-03 has better bass definition and articulation. The BL-03 has slightly more natural sounding treble transient delivery. The ZSX has more presence and immediate clarity but its lower treble can be harsh. The ZSX has more air. The ZSX has better imaging and instrument separation. It is much easier to get a good seal using stock tips with the ZSX. Because I need to use double flange tips with the BL-03, the ZSX is more comfortable. The BL-03 has worse driver flex. The ZSX is easier to drive but is much more prone to hiss. The ZSX does not come with a bag or carry case, while the BL-03 comes with a Blon-branded pouch.

KZ ZSX [$35] vs TRN V90 [$38]
ZSX vs V90.jpg
The TRN V90 is a five-driver (4BA+1DD) hybrid IEM. The two IEMs have very similar tunings, but the V90 has even more sub-bass than the ZSX and has a more elevated lower treble response. Despite this, the V90’s treble is smoother-sounding than the ZSX’s. The V90 has more defined, better articulated bass than the ZSX. The V90’s upper midrange is a touch more forward than the ZSX but has no issues with sibilance. The V90 has better clarity and detail retrieval. The V90 has better imaging. The V90 has slightly worse driver flex. The V90 has less hiss. The V90 has the same venting issue as the Simgot EM1, where if the inner vent is covered during insertion, the sound produced by the IEM is muffled, and must be gently tugged away from the ear to restore proper clearance. The V90 is more comfortable.

The KZ ZSX is a good budget hybrid IEM with no deal-breaking flaws at its price point. However, the similarly priced TRN V90 edges it out in terms of raw sound quality. Both IEMs present different and distinct usability challenges, with the ZSX being potentially uncomfortable depending on your ear size and shape, and the V90 having an annoying venting issue. Of the two, potential buyers should purchase the IEM with the usability concern they personally find less worrisome.


100+ Head-Fier
Pros: A bigger, better ZS10 Pro
Same fun sound, but more balanced now
Best sounding KZ today
Cons: Bass is still big, a bit slow, and not as precise as more expensive IEMs
Shell sticks out of your ears like a Frankenstein bolt
Treble is a big improvement, still can use more richness compared to more expensive IEM or the Blon BL-03
The stock cable needed an update for the ZSX
TL;DR It is everything good about the ZS10 Pro but better. KZ still needs to tighten the bass and thicken the improved treble.

Intro: The KZ ZSX is the latest hybrid IEM from KZ utilizing 1DD and 5BA. Coming from the ZS10P, that is an extra BA which happens to be a new model fo KZ called the DWEK (actually 2 DWEKs used in the ZSX). On paper, that is the biggest change from the ZS10P.

Packaging: New fancy packaging for the ZSX.

Cable: Same cable as the ZS10P. I wasn’t very impressed with the ZSX with the standard cable. I have no proof, but some of the initial reviews saying the ZSX is a side-grade to the ZS10P or this mids were probably using the stock cable. I went with a 16 core copper and it really adds some thickness to the bass and mids. The KZ silver/gold is also better than the stock cable. I wasn’t a cable believer until the ZSX. I had the same cable on the ZS10P and I do not think it changes the sound much at all.

Fit: Not the same as the ZS10P. For me, the ZS10P was the best fitting KZ and the flat back always feels flush even if it sticks out a bit. The ZSX is more like Frankenstein bolts in your ears if you look in the mirror. Fit-wise, they don’t bother me at all but I know this is not the case with everyone. I slipped on the large star tips just as I did with the ZS10P.

Sound: There are a couple of FR charts on here, take a look, the two look very similar up to 7K, the ZSX dips and the extends out further than the ZS10P. I do not think these on-paper changes capture the in-ear experience of the ZSX. I think the sum, the entire package, is more than what I expected from the added driver since KZ hasn’t always been the more is better company.

The bass is very much like the ZS10P which means plentiful but not necessarily fast or refined. With the 16 core cable, it is squarely in basehead territory. This is EDM, rap, pop bass rumble and punch, not Jazz trio precision bass. More so than the ZS10P, the bass punch is impactful, creeping into TFZ No. 3 territory. The TFZ is both more refined and more impactful, but the ZSX is in the ballpark.

The mids are quite similar. As I mentioned, the lower mids will be thicker, meatier with a different cable. What I noticed most from using the ZSX, it is difficult to find vocals that do not sound right. Usually, there is a Prince or Peter Gabriel or Tracy Chapman that doesn’t sound right on a KZ. The ZS10P was the higher range of voices, some Prince or Sam Smith. Generally, everything sounds more like it should on the ZSX, more like a pure dynamic driver, not a hybrid. More natural or organic timbre.

The treble is where the ZSX differentiates itself from the ZS10P. I never found the ZS10P fatiguing or too bright even on fatiguing music from Deadmau5. The ZSX just gives you more texture in the treble, not necessarily any more detail or resolution. Deadmau5 incessant rising notes sound more tolerable up until the drop. Less “steely” is how everyone describes it and I agree. The detail and resolution on the ZS10P were great for the price range and the ZSX retains the tiny vocal details and airy echos. Now the ZSX has a treble to match the bass so it seems much more balanced than the ZS10, again it feels more like a dynamic driver than a hybrid.

The soundstage was good on the ZS10P. Compared to the ZSN Pro, the ZS10P came with a much wider soundstage. I don’t necessarily think the soundstage is any wider or deeper (maybe deeper), but instrument imaging is better, more defined. Hard to put a pin on it, but the psychoacoustics are better than the ZS10P. Maybe it is simply the instruments sounding better so they are more noticeable on more complex tracks.

Conclusion: Despite the minimal changes on paper, the in-ear experience makes the ZSX a worthy upgrade to the ZS10 Pro. Unless your musical preferences go towards fast, precision bass, then it may not be a match for you. For me, no other KZ effortlessly played EDM, pop, rock, classic rock, hard rock, and metal was about as far down that path as I go.



New Head-Fier
Pros: dynamic, punchy bass that is under control
Transparent, detailed heights with futer extension
good wearing comfort and stable housing
Cons: Same spartan accessories as always
Midrange can't quite keep up with bass and treble in technical terms
rare peaks
Knowledge Zenith delights us in regular decency with new in-ears. The "Terminator", or ZSX, is one of the more interesting models. It is strongly based on the signature of the ZS10 Pro, which in my opinion is one of the best models the company has thrown onto the market lately. The ZSX comes with a BA driver more and also the dynamic driver has been replaced. In addition a new design is introduced, which reminds a bit of the ZSR in terms of fit and ergonomics.

The ZSX is astonishingly shining again in a new design and is not just a change of the front plates, as with many other models. At first glance, it looks a bit bulkier, but fits perfectly, making the ZSX even more comfortable than the ZS10 Pro. Unfortunately, the front panel doesn't sit 100% on the body, so there's no smooth transition, but that's a haptic flaw and doesn't change the wearing comfort! In other words, the ZSX looks more robust than the ZS10 Pro, but not as valuable.

When it comes to packaging, Knowledge Zenith goes back to the AS10, which gives us a nice black box to unfold, where the earphone is embedded in foam. Nevertheless, we don't get any other accessories than usual. Cable (with or without Mic) and three pairs of silicone tips.

The isolation to the inside is very good, but the external perception for others is only good average.

On paper, we get almost the same frequency response as the ZS10 Pro. However, this doesn't always mean that the sound is exactly the same. Admittedly, the difference is marginal, but I would still consider the ZSX a small upgrade.

The bass is a bit punchier and more powerful than the ZS10 Pro and therefore a bit more tuned for fun. On the other hand, it doesn't have the same depth, which isn't particularly noticeable due to the prominent, dry and clean midrange bass. As with the ZS10 Pro, we get a bass that you not only hear, but also feel! If the bass of the ZS10 Pro was sometimes a bit too obtrusive, or in rare cases booming, the bass of the ZSX seems even more controlled and more on point, but doesn't quite have the depth. These really aren't big jumps, but a slight fine-tuning.

The mids aren't on the same level as the bass and the treble, but also on a higher level in the price category. Here they don't take anything away from the ZS10 Pro, but they can shine a bit more because of the more controlled bass, because subjectively it doesn't push too much into the mids anymore. Lively and emotional is the stick word here. The upper mids are emphasized as so often, but this doesn't get too intrusive, gives voices a natural tonality and makes guitars crisp. Also voices don't jump directly into the face. It still stands in front of the instruments, but is more on one level.
Everything that makes the ZS10 Pro good here is also done by the ZSX.

In terms of treble, I'd say that the ZS10 Pro has a small advantage over the ZS10 Pro, as does the bass. Knowledge Zenit manages to work out details finely here and scores with a fine resolution and very good expansion. It feels like one of the best I've ever heard from the company in the high frequency range, in relation to the permanent audibility. In rare cases, the ZSX's treble can also be a bit demanding. But if you're already used to this from Knowledge Zenith, you won't have any problems, otherwise the old ZS10 would rather be the choice, with losses in the mid-range.

Where the ZSX doesn't turn out to be a terminator is the stage, but in this segment it is in the upscale range and above all the very good transparency and separation make up for a lot, also in the depth.

Anyone who already owns the ZS10 Pro can confidently skip the ZSX, because the sound benefit is too low for that. However, if you are looking for an audiophile all-rounder with a fun response, the ZSX is just the thing for you and in my opinion it is the best in-ear from Knowledge Zenith at the moment!

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Wretched Stare

Pros: Clear treble and mid details great bass depth and decent soundstage with less of the KZ sparkle some find too harsh. A refined U shaped signature that is most pleasant.
Cons: Typical KZ accoutrements, not the best but acceptable for this range.
The ZSX is one of those stand out IEMs of the new earphone explosion in the past few years. KZ continues to improve and push the boundaries of the bang for buck ratio.

The ZSX Terminator comes in at only $50 US and offers flagship quality features inside with 12 drivers in all.

The sound on the ZSX is easily described as a superbly refined V to U shape with vocals being forward and quite clear mids, bass response is speedy with mid-bass and sub-bass details being clean, the highs have just enough sparkle to them to not make the treble sensitive cringe with certain tracks, it falls off at the right point in my opinion.
I was super sad...I loved the sound from these but for some reason were very uncomfortable. i couldn't wear them for more than 40 min. So I went for the smaller ZS10 Pro.


Headphoneus Supremus
Pros: Powerful and extended bass
Clean and detailed midrange
Extended open treble
No bass bleed
Superb Soundstage
Very musical presentation
Cons: Cable and accessories (as usual with KZ)
I have recently acquired the KZ ZSX and the CCA C12, the latest flagship hybrid models from these companies. They are both very impressive and share many similarities while at the same time having their own character. Here is my take on the ZSX:
The ZSX is the latest flagship hybrid design from KZ (Knowledge Zenith). Dubbed “The Terminator” it is a 6 driver IEM (1DD + 5BA). Whether the name “Terminator” denotes that no further hybrid models will be released is unknown. The Dynamic driver is 10mm in diameter and is a development of the unit featured in the ZS10 Pro, a dual magnet design with a field strength of 1 Tesla. The balanced armatures include two sets of the dual DWEK BA, a mid-high frequency design, coupled with a 30095 driver covering the extreme HF.

The IEMs arrive packaged in a black box similar to that supplied with the ZS7 with the earpieces displayed in a foam cut-out above the KZ plaque seen in other premium models. The words “12 Units Hybrid Technology Earphone” are printed below. Under this cut-out you will find the detachable cable, a set of three Starline-type tips and documentation. A set of plain soft silicone tips with a medium bore are pre-fitted on the IEMs. The shell is a new design with the faceplates finished in a matt charcoal colour with “12 hybrid” written on it and the resin underside finished in a deep greenish colour (called cyan). They look very smart indeed. There are two pinhole vents on the inner surface of the earpieces. The fit was very comfortable with the “fin” on the end of the earpiece providing stability. Isolation was also very good.

The detachable cable is identical to that supplied with the KZ ZS10 Pro. It has a clear plastic connector (known as “Type C”) with the pins covered in a plastic shield. It is still possible to use other cables, which can be plugged into the protruding sockets on the IEMs. The cable itself is composed of braided copper and has a very long section between the chunky Y-split and the earpieces and as a result is somewhat prone to tangling. The plug is the usual right-angled plastic 3.5mm TRS type. It would have been good to see a more premium cable with a flagship model, and please, KZ, can we have a chin slider?

The earphones were left burning in for over 72 hours before testing and included tracks of white and pink noise, glide tones and other audio conditioning tracks. After this I used a Hifi Walker H2 DAP with a Fiio A5 amplifier and a Sony NWZ-A15 for evaluation. The supplied tips were used but I changed the cable to a 16 core silver plated one from TRN.

The immediate impression was of a huge soundstage, powerful bass and a lively engaging presentation. It reminded me of my favourite KZ so far, the ZS7, but with an improved more forward midrange, better staging and layering and a more extended treble. Sensitivity was good with adequate volume obtained via the headphone socket of my DAP but a more authoritative and controlled sound was obtained using an amplifier.


The bass performance of the ZSX was excellent. Starting in the sub-bass, extension and power were first-rate. Depth was impressive while still retaining good texture and clarity. A good example of this was in Jonn Serrie’s “Land of Lyss” from his “Midsummer Century album. This track contains some of the deepest sub-bass you will hear and the ZSX handled it with aplomb. I was able to hear more detail here than ever before with the deepest notes being reproduced cleanly and with low distortion. Orchestral bass instruments also benefited from the ZSX’s ability in this region. The bass drum and timpani in Holst’s “Uranus” performed by the LSO under Andre Previn were very impressive and possessed great impact and immediacy along with weight and power. The mournful trudging of the double basses in “Saturn” were also testament to the cleanliness of the bass with remarkable detail and resolution. Popular music too, sounded good with the bass guitar and bass drum rhythm section in Al Stewart’s “Year of the Cat” being nicely separated and defined, yet combining to produce a very satisfying foundation to the track.


The midrange performance carried on where the bass left off with good resolution and separation, and not suffering from any bass bleed. The complex guitar arrangement in Ray Lynch’s “Over Easy” depicted this perfectly. Each instrument was clearly defined and at the same time, beautifully integrated with the whole. There was good transient attack, excellent portrayal of studio ambience and accurate stereo imaging. Electronic music enjoyed a particularly clean reproduction, with Mark Dwane’s “Geoglyphs” from the “Variants” album displaying superb “slam” in the percussion and clearly-defined synth layering. The whole combining to produce a really entertaining result. The tuning of the new DWEK dual BAs certainly seems to be very successful. There was a little emphasis towards the upper midrange which occasionally resulted in a sharper tonality but this only occurred on certain tracks. In general the midrange was very well-tuned. The modern tonalities in Elizabeth Maconchy’s “Proud Thames” overture played by the LPO displayed excellent timbre and the differentiation of the brass and woodwind sections was well handled with good integration and thus preserving the musicality of the piece.


The treble was clean and well-extended, which was, I feel, due to sharing the upper register between the DWEK units with a single 30095 driver which, I would guess, has a higher crossover frequency than in former designs like the ZS10 Pro. This resulted in a very clean reproduction with few of the harsher or peaky artefacts seen in earlier KZ models (excepting the ZS7). The 30095 unit would appear to have been well-tuned here. Richard Burmer’s “The Forgotten Season” from the album “On the Third Extreme” possessed a clean, smooth tonality in the treble with excellent separation and detail, having a kind of “etched” quality. This also manifested itself in Matthew Clifford’s “Accumulus”, a kind of synthesiser multi-tracked symphony from 1989. Incisive flute-like synth patches soared above the bass accompaniment in superb style. The high string melody in Britten’s first “Sea Interlude” played by Andre Previn and the LSO was clearly depicted. Set against the scurrying woodwind figurations and supported by deep bass drum, it retained its detail well and stood out clearly from the accompaniment.


The soundstage of the ZSX was one of its best features. In fact it possessed the most impressive spread I have heard in an IEM. Width, depth and height were all of high quality, enabling the production and the character of the recording venue to be appreciated fully. This airy soundstage endowed the ZSX with an open, relaxed presentation and well-recorded pieces displayed an impressive sense of space. Vangelis’s “Theme from Antarctica” was a perfect example. Synthesised bass, drums, lead voices and percussion effects assailed the ears from all directions, all contained within a huge, cavernous acoustic. Classical music also benefited from this with accurate imaging and positioning of instruments within the ambience of the concert hall clearly defined. The second movement of Britten’s “Sinfonia da Requiem” was very impressive in this regard, with the brutal percussion scoring impressively powerful and precisely placed within the stereo image.


The ZSX impressed in all areas. With new components, including a revised dynamic driver and DWEK dual BAs, KZ have really “nailed it” with this model. Powerful yet controlled in the bass, clean and articulate in the midrange and smooth and detailed in the treble, added to this was a wonderfully expansive soundstage. All of this came together to produce an impressively musical IEM which combines the impact and entertainment of the ZS7 with the detail and resolution of an all-BA design like the CCA C16 or A10.

Released at the same time as the CCA C12, it is tempting to compare the two. These two IEMs share the same components but in a different shell design and internal configuration. Traditionally, KZ IEMs have been “V-shaped” whereas CCA models have been tuned with a more neutral signature. This is also the case here.

The ZSX has a gentle V profile but does not suffer from bass bleed, nor is the midrange notably recessed. There is a slightly emphasised bass region and a mildly raised upper midrange and treble but this did not produce an unbalanced presentation. The soundstage is very large and the tonality somewhat warmer than neutral. As a result, the ZSX displays a very musical character. In fact, “character” is a quality with which the ZSX imbues each track and the overall tonality more resembles a full-range DD design rather than a hybrid.

The CCA C12 on the other hand, sounds clean, clear and detailed in the manner of an all-BA IEM. The overall effect is like adding a DD to the existing A10. The tonality is brighter than the ZSX which gives the impression of more detail, though when examined closely, the ZSX does not lack any resolution in this area.

The similarities between these two, I feel, are closer than the differences, which is unsurprising given that the same units are employed in both models. It is more a nuance than an obvious contrast, but the differences, though subtle, are there and may influence a choice between them according to taste. However that may be, it is undeniable that the ZSX is the finest IEM to date from KZ.
Here's a reviewer who knows his BA drivers. We get the added bonus of a comparison with its "sister", the CCA C12. No disguised hype-train for another make here, either. Thanks.