Disclaimer:
I would like to thank Cecelia and Knowledge Zenith for providing a review unit of the ZAS. Rest assured that my impressions written in this review are my own personal thoughts and opinions and in no way influenced by outside parties.
I am not an expert in this hobby nor claim to be an audiophile. I just love listening to music and am fond of writing articles.
Introduction:
The KZ ZAS is a 1 DD + 7 BA hybrid currently selling for roughly ~60 USD on multiple online platforms. The DD used in the ZAS is the dual-magnetic XUN driver with KZ’s own “updated” blacked-out BAs. There are two colorways available – silver and black (mic, no mic), with an impedance of 24 ohms and a sensitivity of 109 dB. Connection type is “Paragraph C.”
Oppo Reno 4 > Earstudio HUD100 MK2 (bypass, low power) > Transducer
The KZ ZAS is easy to drive and doesn’t require further amplification. A phone will do.
Build and Comfort: essentially the same shell as the KZ DQ6, only slightly larger and lighter. Fits excellently well for my ears without any discomfort and is surprisingly very secure. It is not resin-filled, and the IEM itself is extremely light for its size, too light even as it doesn’t feel premium at all (quite cheap-feeling on hand). I assume it’s because of the thinner/less dense resin used (compared to DQ6), as well as the acoustics chamber.
Faceplate is plastic, looks good on pictures, but feels cheap. There’s a rough edge at the pointed part but shouldn’t irritate your ear. It’s indicated in the marketing materials that the gold outline of the faceplate is made of metal but it doesn’t feel like it.
Nozzle is the newer KZ style, average length but below average width. You will encounter issues with aftermarket tips and I suggest that you use a nozzle adapter (I just DIY’ed mine from a foam tip I don’t use). Insertion depth will depend on the ear anatomy and eartips used.
One exciting thing regarding this model is that it now comes with a new 8-core cable. Quite thin for the number of strands it has. HOWEVER, it is very supple, light, comfortable and doesn’t hold the “rolled” shape and is a big improvement from their previous stock cable. I do have an issue with the left preformed earhook – it’s shaped awkwardly. There are several fixes for this: 1. reshape it so that it perfectly molds to your ear with some heat (I usually use a hair dryer), and 2. just remove it entirely (would be more prone to tangling). It doesn’t have a chin slider, but the jack is relatively heavy (metal) and feels high quality. Splitter is quite small and is also made of metal. Connectors are plastic.
Isolation is above average due to fit and shell size.
Package: 3 pairs of silicone eartips (S/M/L; not usable for my ears). Paperwork. 8-core cable.
*size comparison of DQ6 (left) and ZAS (right).
*KZ Au, Ag, Cu cable (left) and ZAS stock cable (right)
Now, onto sound:
For this review, the IEM was left in stock mode, without mods other than using whirlwind tips (w/ nozzle adapter), as well as switching to the KZ Au, Ag, Cu cable for aesthetic purposes, with a listening volume of low-medium to medium. As per my testing, I have found the ZAS to be tip-sensitive. Tip roll per user preference.
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Bass: monsters. Whatever KZ sound engineers did to the ZAS to reach this deep is nothing short of exceptional. Sub-bass frequencies are easily reached and has serious rumble. Mid-bass contains heavy punch. Texture and control are sub-par considering the price. However, I have a feeling that the XUN is not the only one handling this region. From my experience with the DQ6, the XUN driver is of the faster side, both attack and decay-wise. The ZAS is different. It has a tendency to sound boomy especially with continuous bass hits. There are songs where you notice that it feels like a clearer (and cleaner) bass response is hiding behind the bass cannon persona. Good thing is that both play around the same speed but would show incoherency in bassier tracks.
Midrange: a mixed bag. Let’s get the obvious out first – it is recessed (excluding upper midrange a bit, but still applicable), close to the point of sounding drowned by the bass. Female vocals sound fine for the price, showing hints of thinness. Male vocals, meanwhile, are a different story. As I have mentioned a few sentences back, most of the midrange is recessed, and this include male vocals. It also has a tendency to sound nasal in some tracks. Peak is exactly at 2 kHz. No observed shouty-ness in my listening volume (low-medium). I do have to note that the midrange of the ZAS is… soft. Electric guitars don’t have bite, toms lack definition, and vocals don’t deliver emotion (subjective). One good takeaway from this is that the ZAS is very much fit for casual use.
Treble: mellow, non-fatiguing, and smooth-sounding but rolls-off after lower treble. Air extension is alright, nothing amazing (though almost inaudible when listening to music). IF you listen to non-bass focused tracks, you will notice how *mature* this treble tuning sounds like. BUT, OOTB, especially if you got used to more energetic highs, it will sound dead and muted at first, most especially due to the bass quantity/quality. In my experience, after a few songs, my ears got used to the signature. This is very, very different from the two other KZs I’ve tried (DQ6 and EDX) as well as the KZ hybrids I’ve read about. I have to say, this tuning would have been fine, fantastic even, if not for that bass. No sibilance nor harshness, at all. Lacks sparkle and brilliance but doesn’t show splash (though decay is faster than natural, as expected of a BA).
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Timbre: Not the most organic, but also not unacceptably artificial. Decent considering it has 5 BAs but definitely shows hints of that BA timbre especially in the vocal region. Treble not so much due to its laidback character.
Soundstage, Imaging, and Separation: Soundstage doesn’t favor any dimension and is spacious (shell size plays a role). What is exceptional for the price is the depth due to how well-extended the ZAS is in the sub-bass region. Imaging, as well as separation, is as expected of a multi-driver IEM – good. Each instrument has a place of their own and won’t blur along the edges.
Detail-retrieval: Assuming that your ears have been “saturated” by the signature, it still won’t show
Unless you really look for it, of course. The ZAS isn’t tuned to deliver a detailed and transparent sound. Sup-par detail, micro or macro in the price bracket it lives in.
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To EQ or not to EQ?
With Wavelet/AutoEQ being talked about in a thread I participate in, I remembered that I had said application download in my phone. And so, I run it, plug in the ZAS directly to the phone, search for the ASX, and set the EQ strength to 45%. The selection of the ASX EQ preset is under the assumption that the tuning shares similarities with the ZAS (can’t prove because I don’t have the aforementioned IEMs nor have I listened to them, but I have seen the graphs and they share the same generation BAs
). As far as I know, the AutoEQ preset is patterned to mimic the 2019 Harman target. Do correct me if I’m wrong. Thank you.
So, how does it sound? Good. Like really good. Mid-bass is toned down to a degree (also sub-bass by a little) but is still present unlike full-blown Harman. Bass, in general, is definitely elevated (retains that rumble). Texture shows more and bass lines are cleaner. Midrange, and in extension vocals, show better resolution and definition (less recessed and airier, as well). The ZAS female vocals (w/ EQ) is a treat for female vocal lovers like myself. Instruments now exhibit texture. Treble has more, much appreciated at that, presence and better extension (finally some air and brilliance). Soundstage has even more “space/air” around the instruments. More detail perceived due to the increase in the upper frequencies.
2 kHz peak is also lessened and the preset favors ~3 kHz, which is much, much better for my ears.
*ASF and ASX EQ presets share similarities. Choose based on what your ears like more.
**EQ strength refers to how much dB is being added/deducted to or from the specific frequencies. Choose based on what your ears like more.
***I didn’t perceive any distortion when EQ was applied (indicated strength). YMMV due to differences in audio set-up.
Conclusion:
Is the ZAS a representative of Knowledge Zenith’s new image, as well as its tuning? If you ask me, I do think it is. However, as the ZAS appears to be of the first pages of this next chapter in their continuing legacy, we can only hope that it gets better from here on. A new and way better stock cable, excellent fit and comfort considering the size of the shell, great bass extension even at 2x the price, and relaxed highs – these are what makes the ZAS a compelling choice. However, you will have to deal with a whole lotta bass, recessed midrange, non-existent detail and a feels-cheaper-than-its-price-suggests build.
In stock tuning, I would definitely not recommend the ZAS for its price, unless you really like them bass. HOWEVER, if you are open to EQ, then it’s a 50-50
Just needs a little cleaning up.
No EQ – 2.5/5
With EQ – 3.5/5
****If you have other questions/concerns with the IEM mentioned, feel free to message me****