ChiFi Defenders

Ratings

Pros

• Four switches, great versatility in their profiles.
• Very good bass, with a great behaviour, even in its highest position.
• First midrange with body and warmth, which makes them pleasant to listen to.
• Low weight, good ergonomics.
• Open sound sensation.
• Acceptable technicalities.
• KZ tips.
• Transparent construction, good outer plate design.

Cons

• KZ tone.
• Treble too high for my taste.
• Minimal accessories, very tight, stiff cable. KZ simplicity.

Purchase Link

https://www.linsoul.com/products/kz-zs10-pro2

Link to the Store

https://www.linsoul.com/

Introduction

Believe it or not, it’s been more than 5 years since I created my blog dedicated to portable audio and I still haven’t reviewed any KZ model. What used to be the brand I bought the most as a hobbyist, the salt and pepper of the most tasty and primitive Chi-Fi, has never been reviewed in this blog. Actually, KZ, the brand under which Guangdong-based Dongguan Yuanze Acoustics Technology Co., Ltd. operates, was founded in 2008, making it a legacy brand by Chi-Fi standards. Its founders are Keith Yue, a former Audio-Technica engineer, and Zen Li, a Western-trained classical musician. The name KZ is not only a nod to the founders’ initials, but also an abbreviation for «Knowledge Zenith». The company offers an impressive range of low-priced headphones that mimic the shape of many moderately priced headphones from leading brands. KZ originated, in 2013 advocated the ultimate, fashion and simplicity focusing on the faith of revolutionary pursuit of the ultimate attitude towards life forward. Truly, there are few brands that represent Chi-Fi in its purest state like KZ. But, really, the brand persists in a continuist idea of models within an own style that allows any fan to say: you can tell that this model is KZ. Its seal of identity is very strong, but it could also be a brake on its evolution. The model I am going to review is the KZ ZS10 Pro 2. As a good fan, I have the first version of the ZS10, a classic and sharp analytical version within KZ. Many years later, the KZ ZS10 Pro 2 is my first KZ that I am going to review. Now my mind is clear from the frenzy with which I used to buy many KZ models and after more than 100 reviews I have a different perspective on this legendary brand. Let’s see what these new KZ ZS10 Pro 2 can do.

Specifications

• Driver Type: 10mm dynamic driver + Dual 31736 BA x2.
• Precise 3-way crossover technology.
• Custom 4-level tuning switch.
• Frequency Response: 20Hz-40kHz.
• Sensitivity: 108±3dB.
• Impedance: 25-28Ω
• Jack Connector: SE 3.5mm
• Capsule Connection Type: 2Pin 0.75mm
• Cable Length: 120±5cm.
• Cable Type: silver plated conductor.
• Price: $50.39

Packaging

KZ is distinguishable from its presentation. The KZ ZS10 Pro 2 comes in that classic small white box, measuring 94x73x33mm. There is a real photo of the IEMS on the front, specifications and other brand information on the back. This case slides vertically and features the IEMS inside a plastic mould at the top and a box at the bottom. It is protected by a transparent plastic sheet that acts as a lid. Inside the box are the accessories, which are:

• The two capsules KZ ZS10 Pro 2.
• One cable with remote control and microphone.
• One pair of black foam tips.
• Two pairs of silicone tips type KZ, medium and large sizes.
• One metal pin to operate the switches.
• One instruction manual.

KZ power: capsules inside plastic moulds, instead of using foam moulds. Cable still looks too basic, even though it is silver-plated. No carrying case, no bag. Just 2 pairs of KZ tips and, best of all, the metal pin and the foam tips. A step forward would be to improve the cable, as, in my opinion and although I am not a believer in cables, it limits the potential of the model.
Low level of accessories for a model that already costs 50$.

Construction and Design

The capsule shape of the KZ ZS10 Pro 2 is semi-custom. The outer face appears to be made of a metal alloy. The surface is polished, smooth and shiny. It has 5 slots which are protected by a grille underneath. There are 3 Torx screws that anchor the outer face to the body of the capsule. On the edge you can read «NEW GENERATION HYBRID». The inner face is all transparent plastic. The rim is thick to accommodate the 4 switches. The capsule connection interface is typical KZ, with the 2Pin 0.75mm connectors mounted on an oval that overhangs the capsule. The inner face is smooth and rounded, not seeking a wavy shape beyond the edge, with no protrusions. The nozzles are integrated and made of the same material. They have two diameters, the initial diameter is 5.3mm and the crown is 6.1mm. The approximate length is 4mm. The nozzles are protected by a fine metal grid. There is a hole in the centre of the inner face, which coincides with the centre of the dynamic driver.
The cable is a classic two-stranded soldered cable with a silver-plated conductor. This is perhaps the most relevant thing about the cable. The rest is the typical 90-degree plug made of translucent white plastic. The splitter piece is a piece of transparent plastic. It has a remote control and microphone mounted on an elongated white plastic piece. The connectors are the classic angled connectors. All connectors are gold plated.
The cable is stiff and takes shape. I don’t like microphone cables although I understand that they can be really useful. But KZ could improve on this and make better microphone cables. Very few brands have invested in improving an accessory like this. It may seem obsolete in the widespread use of TWS. But I think that improving the microphones of IEMS cables is a very good idea. In my opinion and beyond the usefulness of the remote control and the mic, the cable begs to be replaced immediately.
The capsule’s construction is classic, with a plastic inner face, whose greatest virtue is its level of transparency, allowing the drivers, cables and crossover to be seen. The elegant and distinctive seal is set by the outer grille which, with its grooves protected by slots, generates a more open sound. KZ is true to its designs and remains anchored in a look that moves on the edge of the more economical price point, both in external construction and accessories, perhaps to maximise the technology used in the drivers that produce the sound. However, all of the drivers are also manufactured in-house, so it is possible that much of the price is invested in R&D. But that doesn’t detract from the fact that the look of the IEMS KZ still has that well-finished, but cheap look.

Adjustment and Ergonomics

Capsule of medium size, light, semi-custum on the outside, but smooth and curved inside, without protuberances on the rim. Good inclination of the nozzles. The length is suitable for a shallow to medium insertion. Thick rim due to the 4 switches. Allows some rotation until it snaps into its end point. With the right tips the fit is remarkable, with a good fit and good insulation. The classic internal shape, the good orientation and size of the nozzles ensure a very proven and reliable ergonomics, without artifice, but without a superior fit in its anchorage. KZ has adopted the safety of a design without internal protrusions and this gives it a wider and more universal comfort index.

Sound

Profile

With 4 switches, the KZ ZS10 Pro 2’s move from a bright mid-centred profile to an excited and rising W-profile. The switches barely modify the treble, but modify the lower range down to 500Hz or 600Hz. The first three positions only add 2dB at the lower end of the subwoofer, while the fourth position has a difference of about 4dB from the previous step. I would have preferred more distance between each step and a fourth step with more bass boost, almost at Bass-Heads level, to gain versatility. Undoubtedly, and coming from previous reviews that I alternate powerful IEMS in bass, with neutral IEMS in bass, this time I go back to the fold and prefer the tuning with the switches in the higher bass position (1111 or 1110). As the ZS10 Pro 2’s profile is excited in upper midrange and treble, I prefer this tuning with higher bass to compensate. It is true that three of the tunings are lighter in bass and I might be skipping the more balanced profiles. But as a good bass lover, if I have a choice, I usually go for the more bass-heavy profile.

Bass

The ZS10 Pro 2’s bass is quite dense and deep, generating a good sense of volume, presence and also enjoying a noticeable level of darkness, something that supports that more corporeal and physical feel. There is a certain rubbery character that gives a subtle rougher feel, with a more pronounced texture. However, the impression that strikes me the most is that dark colour, which creates a dry, full and hard appearance, as if it were a rather deep barrier. In the pure tone test you can see that strength from the lowest note. There is an obvious, strong, powerful sensory character at the lower end, quite dark, but this is coupled with a more audible ripple effect that slightly spoils the very physical, yet good, experience. This is possibly some of the deepest, most sensory bass I’ve tried lately. And that’s commendable in a mere $50 IEMS. In this test, the demonstrated behaviour has been excellent for the price, as it has been powerful, physical, sensory, quite shattering, very deep and dark. On the other hand, it is not a slow bass, it is not the fastest either, but it has quite good control. So you could say that it is somewhere between a medium-fast bass in its execution, with a little bit more punch due to its level of power and energy. It is true that when executed it can take up quite a bit of space, which can cause a certain level of fatigue. However, it picks up quite well for all the volume it takes up and the strength it demonstrates. And that’s something that comes through in the dirty, complex and unfiltered bass test. The ZS10 Pro 2s perform remarkably well in these more difficult passages, demonstrating very good control, keeping the bass in check, despite its power. It’s true that it tries to simplify it slightly, losing some ability to follow all the faster bass lines, but it doesn’t lose pace or go off script, inventing things that don’t exist, but in the faster passages it tends to simplify the performance. In quieter passages you feel a better layering and a more efficient generation of layers.
In my opinion, the bass is quite enjoyable for its power, presence, dark colour, density, depth and punch. Undoubtedly, the ZS10 Pro 2s have a thunderous sub-bass that is worthy of note. It may not be the most skilful, resolving or authoritative, but it does offer a distinctive experience that has a certain magnetic appeal as a bass-lover.

Mids

The midrange carries a certain level of darkness and warmth from the bass, which is combined with a restrained character in the transition from the upper midrange to the first treble. There is a clear control zone that shades this transition, something that affects the overall colour of all the midranges. In my opinion, for the better. The ZS10 Pro 2s have a peak at 3kHz that contrasts with a 10dB difference at the 800Hz mark. There is obviously some imbalance, but the first part of the midrange is better represented. In this way I cannot say that the male voices are lean or light. They are not completely full, but they do have a good sense of body, a juicier base, with a presence closer to the listener and a more realistic and natural timbre. Admittedly, that conjunction between the nuanced early treble and the level of darkness in the lows makes the first half of the midrange more muted, but also richer and more complex. In contrast to many lighter IEMS in this area, I have to say that I was pleased to hear again a denser and fuller first half of midrange than on those previous occasions, without it really being a full first half. But it is a big plus. It is clear that this is achieved with the 1110 or 1111 switch positions.
On the other hand, that sense of darkness is mixed with a certain overall airlessness in the midranges. There is good definition, but also a somewhat nuanced character that limits the brightness and sense of transparency. The early treble has been sieved and, as I have already mentioned, it has a double effect, maintaining that initial level of darkness, providing a little more body and physicality, but also limiting the amount of brightness, transparency and energy. The notes have a midrange thickness in the midrange, slightly rounded at the top. However, there is a higher, final sparkle that gives it a less realistic metallic character. There is a slight mismatch in the representation of the higher harmonics, which prevents it from sounding more natural. If one can survive this alternating sensation, the midranges can become pleasing. Otherwise, one may get the impression of a certain incoherence in that more explicit brightness. However, that can be fixed by using other tunings with less bass. In that respect, the switches will return all that glare that is counteracted in the maximum bass position. In this respect, the upper midranges will again be splashy, more transparent and clearer. But they will also reveal that more BA, sibilant and penetrating character of the KZ drivers. So the end result becomes a series of advantages and disadvantages, which don’t quite work out.

Treble

KZ does not get rid of this BA quality in its treble, although it tries to soften it. Perhaps a less energetic extension would have been more appropriate. The transition from the upper midrange to the first treble is slightly controlled. KZ has sought to reduce the energy level of the first treble. And it has succeeded in doing so for the lowest tuning. For the rest of the tunings, a powerful presence persists. But there is something that doesn’t quite add up, a certain overall incoherence. And the downside may lie in a rather emphasised second part that prolongs a thinner and more powerful treble, towards a somewhat more dangerous extreme. At the end, again, another contrast in a deeper air zone. The result is a thinned treble, subtly sly at first, elevated and more energetic later and slightly stifled at the end. Perhaps not the best response for the rest of the range. Nor is it the best performance from the KZ drivers, which still show that typical KZ character. I would have preferred a more coherent and balanced tuning in this upper range, but the obvious W profile is evident with a final peak at a point somewhat more unpleasant for some listeners.
It is clear that the switches make the treble more dominant in the overall sound. It should be remembered that the ZS10 Pro 2’s move from a bright mid-centre profile, all the way up to a sharp W. The increased bass presence can drown out/counteract the treble. The increased bass presence can drown out/counteract the treble. But as the switches are turned off, the upper midrange and treble stand out in clarity and feel more energetic.

Soundstage, Separation

KZ with their BA drivers have always been an example for the level of resolution. In this case there is a clear focus on macro detail. While micro detail is discernible, but not in a completely obvious way. In the lower bass switch positions, the upper midrange and exalted treble are more penetrating and the detail in this area is persistent. On the other hand, midrange details feel more distant and overshadowed by more powerful and obvious nuances. The loss of depth due to the lack of bass means that the layering is not as good and those background details are diluted. The scene gains in depth at positions 1110 and 1111, some level of transparency and clarity is lost. But I don’t perceive a very large scene size. I have a feeling of a rounded scene, with good laterality and height, but with a depth in the line. Hence the sound layering is not very powerful. On the other hand, there is a certain sense of openness, of a certain more spacious character, and this may be due to the external grilles, which can give the sound a certain more gaseous or volatile capacity, adding a pleasantly more surrounding sensation to the whole.
There is a good level of precision and resolution. But the mix of more powerful bass and energetic treble creates some muddiness to the sound and a little more airy feel is missing. The imaging is good, remarkable for the price, becoming evident depending on the position of the switches.
However, I was hoping for a little more micro detail and more obvious informative power, something I remembered from the earlier ZS10s.

Comparisons

Simgot EA500 LM Gold Filter

The frequency response of the KZ ZS10 Pro 2 with the switches in the 1111 position is quite similar to that of the Simgot EA500 LM with the gold filter. It is true that the Simgot costs $80 and the KZ $50. The difference is justified by a rather good metal construction, more complete packaging and accessories. It is true that the LM can also be tuned differently, but using different types of mouthpieces, which is not as quick as changing a switch, as is the case with the KZ.
The ergonomics of the KZ are quite good, with a very light weight. The downsides are that they are slightly larger than the Simgot and they are also thicker. The LM’s are heavier, but smaller and less thick, which makes them fit better in my ears. In the long run, despite the heavier weight, the LMs are less uncomfortable for me.
The LMs are somewhat more sensitive than the KZs, at the same amplifier volume, they sound louder.
As you can see in the FR comparison, both have a similar profile. There is a little more sub-bass in the KZs, with a slightly cleaner bass. There is more energy in the transition from upper midrange to first treble in the Simgot, but then they are somewhat smoother, avoiding that peak in the second treble that the KZs do have.
Bass is thicker, darker, more sensory and deeper in the KZs. The Simgot’s bass is drier, more restrained, tighter and quicker, with less punch and a quicker fade. Great behaviour in the pure tone test in both models, with very good behaviour and a similar execution of each tone. The KZs are slightly darker and slightly more sensory. But the level of resolution and technical skill falls on the side of the Simgot.
In the first half of the KZ midrange there lingers a halo of warmth, a touch of darkness and a thicker presentation. The Simgot is subtly thinner, but clearer, sharper and more vivid, with better definition.
In the upper mids, the KZs are not as clean and crisp as the Simgot. The KZs, comparatively speaking, sound a bit nuanced in this area, less transparent. They are less projected and have a lower energy point in this area. The Simgot are more vivid, splashy and dynamic in this area, they have more projection and lift. But the greater power also implies a more fatiguing, perhaps more sibilant point. Still, I prefer the timbre in this area of the Simgot. You feel a higher level of resolution in the Simgot, something that gives it a higher point when it comes to revealing micro details. They also have a wider, more extended soundstage, more distant from the listener. They sound bigger. The KZs offer a sense of open sound, but the soundstage is more intimate. Details are closer together, less separated, their background less discernible. Technically speaking, LMs are superior.
In the treble, the timbre of the KZ seems to me a bit weirder and unbalanced. With an initial nuanced control and more energy in the second part, the first treble is thicker and the second is sharper, generating a point of imbalance for my taste. The Simgot have a behaviour more suited to my tastes, with a more natural and crunchy initial expressiveness, then they sift smoothly, although they have a better airy feel than the KZ.

Conclusion

The KZ ZS10 Pro 2 is a good example that KZ is not on the wrong track. I still find it to be a genuine KZ model, both in its aesthetics and in its sonic background. Widely versatile with its 4-switches, with a profile that goes from bright mid-centric to a rising W. KZ seeks to nuance the classic sound of their BA drivers, but that chink persists in the brightest positions. On the other hand, they become quite resolving IEMS for their price level. I really like their bass in the highest position. They may be too much for some, but they show a great behaviour and have a great weight that gives the sound a lot of personality, body and presence. The first midranges carry that goodness and maintain that physicality that I miss in even more expensive models. The second half of the midrange is combined with a somewhat controlled entry into the treble, which gives the sound a certain nuance, a search for smoothness. But, in the end, it feels somewhat unbalanced due to a more energetic second treble. The second part of the sound may be very good for many. But I find it too energetic in the switch positions with less bass and somewhat less coherent in my preferred 1110 or 1111 position. Still, that doesn’t detract from the fact that they are a remarkable and very versatile set for a price of $50. The question is whether KZ will ever stop opting for their classic minimalist packaging and very fair level cables. On the other hand, I’ve always been a big fan of KZ tips. When will KZ tips with foam-filled grooves be available?

Sources Used During the Analysis

• EPZ TP50.
• Tempotec V3.
• Burson Audio Playmate 2.
• Aune X8 XVIII Magic DAC + EarMen ST-Amp.