KZ Zenith Review (IEM)

TL;DR for those short on time or not inclined to read the entire review (tables are broken so I am using an easy paragraph with Pros and Cons until someone fixes it):

Pros

  • Mature, well balanced, full-sounding IEMs with good technical performance, good bass quality and timbre
  • Unique design and great build quality
  • The new KZ packaging is finally up to par with the expectations

Cons

  • The basic curve is kind-of polite and the female vocals could use a touch more energy/vividness
  • The cable is worse than most cables in this price range

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Introduction

KZ has been changing something in the direction of their products lately, and the KZ Zenith is another one that popped out from nowhere during this silent revolution of the brand’ portfolio.

Disclaimer: the KZ Zenith were sent to me by KZ so that I could write an honest review. This review represents my personal opinion on the set, it isn't promotional or paid content and I don’t get any revenue from the sales of this product. At the time of the review, the KZ Zenith were sold for about €70 at KZ-audio's website.

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Technical Specifications

  • Driver Configuration → 1 x DD
  • Impedance → 23 Ω
  • Spec-sheet Frequency Response → 20Hz-40kHz 
  • Sensitivity → 108 dB
  • Cable → 1.25m OFC cable with QDC 2-PIN connectors
  • Plug Type → 3.5mm

Packaging

The packaging of the KZ Zenith represents a steep change of direction in the packaging. It’s a well done packaging considering that we’re talking about a KZ set, and it’s much better than their classic packaging. The box contains:

  • The KZ Zenith
  • The detachable cable
  • One set of starline silicone tips (S, M, L sizes)
  • One set of foam tips (S, M, L sizes)
  • Hard carrying case
  • User manual

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Design, Build Quality, Comfort and Isolation

The KZ Zenith are probably the best-looking KZ IEMs to date, especially when it comes to the design. The manufacturing is honestly excellent as well and I struggle to say something wrong about it (in fact, there aren’t any complaints in that regard). Unlike other KZ sets, it’s the first time KZ speaks about the ventilation and the grills underlying the faceplate look like they are perforated. Since this should lead to a semi-open back design, this would explain why the isolation from external noises isn’t excellent with the Zenith in the ears. 

The earpieces are also pretty comfortable, even though the angle near the golden screw could probably bother those with very small ears during prolonged listening sessions (no issues at all in my case).

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Cable

The cable is the same low quality cable all over again, and I really suggest KZ to upgrade it. It’s not only about the appearance, it’s also a matter of perceived quality and absence of a chin slider (which is usually good to have instead).

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Sound

GEAR USED FOR THE TEST

  • DAC: Topping E30 
  • AMP: Topping L30, Fiio A3
  • Mobile phones: Samsung Galaxy S7 Edge, Xiaomi Mi A3, Samsung Galaxy S23 Ultra
  • Moondrop May’s DSP cable with PEQ=0
  • Dongle: Apple Type-C dongle, Fosi DS2
  • Portable DAPs: Benjie S8/AGPTEK M30B
  • Bluetooth Adapters: KBEAR S1, KZ AZ10 
  • Other sources: Presonus AudioBox iONE, Elgato Wave XLR

Amplifier needed?

An amplifier is not strictly needed but I felt like the Zenith were performing slightly better with a tighter and cleaner low-end and better overall dynamics while using a good quality dongle with respect to the average jack port of a laptop or older phone. 

Let’s speak about the sound.

I will refer to the 1110 configuration since I really think it’s the most attractive for this set. I will then speak about the impact of the various positions so that you can have an idea on how the sound changes when the switches are used.

The Zenith are the result of what KZ has been changing lately: it’s a well balanced, full-sounding set that never feels overly bright nor too dark, not lacking bass without being bassy, not lacking treble without being annoyingly bright. And yes, the mids are there!

Starting from the low-end, in fact, we get a proper sub-bass extension that is far from sounding exaggerated: it retains nice control even when reaching very low notes, and even though it’s not the most surprising set you can buy if you want to dig super deep, you won’t feel it’s lacking something.
The bass has good weight, it’s present in the mix yet not to the point of being the star of the show, which is surprising if we consider that this is a KZ set. The bass texturing is nice for the price, there’s enough punch to the bass and what surprises me more is the overall naturalness and realism of the bass (I have never heard such good bass quality on a KZ DD set).
The midrange is not as recessed as on other KZ sets, and thanks to the well mannered bass you get the benefits of the added warmth in the lower-midrange without having a bloated midrange. Male vocals are well done with the right amount of warmth and female vocals sound natural without becoming hot nor sibilant. If anything, a touch more air during the reproduction of female vocals would have been the icing on the cake.
The treble is another selling point of the Zenith being non fatiguing, very smooth and natural. The Zenith aren’t detail-monsters but they aren’t even treble cannons like KZ IEMs used to be, and this natural manner of managing the whole treble (and its extension) without extracting artificial detail is probably what really distinguishes the latest KZ sets from their older products. 

The technical performance is pretty good for a single DD set, with a well-rounded soundstage, on point imaging and enough space between the instruments to have proper instrument separation. If anything, the layering is only average as it struggles a bit with multiple instruments’ layers (its peers in the same price range are almost on the same level). 

How do the switches affect the sound?

Basically, all the switches off mean basic curve with a very linear bass. I think that the basic curve lacks some depth and weight in the low-end, but maybe those who don’t really dig a thicker low-end will like it.Then this is how it works:

  • First switch ON → +1dB bass boost
  • First and second switches ON → +2dB bass boost
  • First, second and third switches ON → +3dB bass boost

The last switch, in combination with the other switches, provides for a full range boost. So if you have all the switches ON you will basically boost the low-end also and have a louder sound. 
If you use the first 3 switches separately, then you still get small bass boosts depending on how many of the 3 switches you're activating, and if you activate the 4th switch alone then you just make the earphones louder no matter the position of the other switches.

I think the basic curve has its own advantages, such as a tighter and slightly speedier low-end, and maybe the upper end has slightly more recognizable smaller nuances. However, the +3dB bass boost with all the three switches on provides for a fuller, richer and more mature sound with better note weight and depth, even though some tightness and speed are partially lost.

Are they something I would use considering my taste and preferences?

Yes, of course.
It’s a well done IEM overall: solid technicalities for the price, natural timbre, smooth treble, enough bass and good midrange presence. It’s a set of IEM that does most things right and I would really struggle to find reasons not to use them if I didn’t have more expensive (and well tuned) sets around me.

Some comparisons:

KZ Zenith (UUUD) vs KZ Saga Bass

Upgrade or not? Well, if you like the super energetic and fun-sounding Saga Bass, you may find the Zenith “too balanced” at times, but in terms of timbre and technicalities the Zenith are way above. Comfort is good on both sets, isolation is better with the Saga Bass in the ears. Even though the Zenith come with better packaging, the cable is the same and this is weird.
I find the Saga Bass more fun to listen to, but the Zenith are technically superior and this is undeniable.

KZ Zenith (UUUD) vs Kefine Klean

The Kefine Klean have a touch more extension in the sub-bass region and slightly more treble energy, so the Zenith actually end up being “thicker” in comparison since the smoother and more rolled-off upper end provides for an overall warmer sound. Bass quality and textures are better on the Zenith, female vocals are more energetic and emotional on the Kefine Klean.Imaging and instrument separation are mostly on par whereas the soundstage is bigger on the Zenith. Build quality is good on both sets, Klean’s stock cable is better, comfort is better on the Zenith and isolation is better with the Klean in the ears.

KZ Zenith (UUUD) vs Sivga Que

Go with the Zenith.The Sivga Que are nice and kind-of unique in their price range but in terms of technical performance and overall sound, the Zenith sound fuller and more mature with a smoother and more versatile tuning. Technicalities are also slightly better on the Zenith. Build quality is very good on both sets, comfort is better on the Zenith and isolation is better with the Que in the ears. The Que come with a much better cable.
It’s not that I don’t like the Que, in fact I actually do, but you get a higher value for a similar price if you buy the Zenith.

KZ Zenith (UUUD) vs Simgot EW200

The Zenith sound pretty warm, the EW200 sound pretty bright. The low-end response is kinda similar but the emphasis on the mid and upper treble on the EW200 make the Zenith sound a bit thicker overall. Male vocals and acoustic instruments are better on the Zenith, whereas female vocals, violins and electric guitars are better on the EW200: pick your pill. Technical performance is on par more or less, even though the resolution of the EW200 is still amazing for the price, especially considering that spring 2025 will mark their 2years anniversary. The soundstage, however, is bigger on the Zenith, as they can offer better width, depth and height. Build quality is good on both sets but the Zenith have a unique design. EW200’s stock cable is better. Comfort goes to the Zenith, whereas isolation is a tad better with the EW200 in the ears.
As a small sidenote, I’d really like to point out how good the EW200 are, being able to compete with recent IEMs without struggling too much. Hopefully we’ll see more sets like it in the future as we really need stuff that stands the test of time.

Final Thoughts

The Zenith were a surprise, both thanks to the tuning and to the technical capabilities. It’s a set that has so many good things, such as the timbre, the bass quality, the treble tuning and everything lead to an IEM that is hard to dislike or criticize. If anything, the basic curve isn’t very attractive or particularly inviting and female vocals aren’t the most refreshing out there, but I really struggle to find real cons and it wasn’t usually the case with KZ.

I really like the new roads that KZ is exploring and hopefully we’ll see better and better stuff from them.