Kiwiears x Z Reviews Serene

A different kind of Zeos collab — bass dialed back, warmth kept intact

I’ve liked a lot of what Kiwiears have done in recent years’ especially on the IEM side — usually incredible value, often with quirky but always interesting tunings. When I heard they were partnering with Zeos Pantera (Z Reviews) on a full‑size headphone, I was curious, especially since rumours suggested this would not be a repeat of the extremely bass‑forward tuning of his earlier Eris Headphone.

So, Serene lands in a different place: less bombastic bass, but with a nice warm tilted sound signature that’s easy to live with day to day, a headphone for a Serene ‘Zen’ experience.

I’ve spent the past week with the “Serene”, and it has definitely grown on me. Initially, I had some problems which I will get to later in the review, but most of these are resolved or at least I believe I understand them. But I will get into those niggles later, but hopefully this review allows you to make a full and informed decision about whether you want to buy this headphone.

But first, let’s look at the unboxing.

Unboxing

The retail presentation is nice and straightforward, very typical of recent Kiwi Ears Headphones.

The sleeve and box outline the collaboration and basic specs, and the headphones are protected in plastic inside the insert:

Finally, opening the box reveals the cable and a manual:

And underneath you see the headphone in plastic protective cover:

Removing the plastic:

The depth of earpads especially impresses when you take it out of the box:

Cable quality is ok, but I did find the stock cable a bit microphonic:

The 3.5mm connectors on the cable are decent enough:

Overall, it is probably better than a Hifiman stock cable (which isn’t really saying a lot).

The cable has the logos on the splitter:

But let’s check out the Serene itself.

Build, comfort, and isolation

The cups have a compact footprint with a striking purple‑tinted grille pattern.

The Depth is very good and the pad foam feels nice to the touch:

The only problem with the earcup design (and for me it was a problem) is the size of the pads. My ears definitely touch the side of the earcups and while I did get used to them after a while, I would have liked wider earpads. I actually tried some alternative earpads, but they all sounded much worse than the stock earpads, so I stuck with the stock ones and mostly got used to the comfort.

ANC Headphone design?

I feel like this design and especially the earpads would be great for an ANC headphone. I even noticed the headband was even designed to pass the cable between each side, a sure sign of a design that would work for an ANC headphone, where typically one ear as most of the electronics and passes the audio to the other via a hidden cable:

Cup rotation is adequate and the headband offers some decent comfort ontop and a healthy amount of extension with low overall weight:

The attenuation of background noise is excellent with the Serene. This is almost into ANC headphone terrority.

During my initial testing, I did bring the Serene out for a long walk (with the CrinEar Protocol Max) and, while not quiet as good as an ANC headphone, the traffic noise dropped enough that it made a very pleasant walk. I also didn’t get that ANC headphone feeling with none of the typical ANC ‘pressure’ build-up.

But this walk did make me notice another quirk: there is a rattle and I think this is a side effect of the plastic “tuning” ring under the pads. It never ruined music for me and got better the longer I walked but it’s worth noting if you plan on using Serene on the move.

Earpad size comparisons

As I mentioned earlier that the earpads are small for an ‘audiophile’ closed back here are some photo comparisons:

Compared to the FT1:

And if I add a ZMF headphone to the mix, you can really see how small the earcups are:

Probably an unfair comparison, but I think it illustrates that the Serene is mostly for medium or smaller ears.

Drivability and sources

So, this headphone is a little harder to drive than I would have expected. I do believe the planar driver is a little too small and is being forced a little too hard especially with the bass and this leads to the headphone needing some power to really open up. It worked well with all my desktop amplifiers, I especially liked it with the Luxsin X9 and the new FiiO K13R2R (review coming soon).

But as a closed headphone, I would like it to work well on the go, and at the office. My preference is more for open backs when listening at home. So, from an Apple dongle it plays ok, but the sound was a bit flat and didn’t open up. With a more capable portable like the CrinEar Protocol Max (boost enabled), dynamics and control improved notably.

Sound impressions

Serene wears its tuning on its sleeve: warm overall with a relaxed presence region and a darker-tilted top end. That recipe suits a lot of real-world music. I especially enjoyed classic rock, Americana/folk, blues, and live-leaning recordings — anything that aims to capture the sense of a performance rather than hyper-etched detail.

Bass

Sub-bass is present but not massively boosted; mid-bass carries warmth without being as bloated as the Eris. The headphone is happiest at normal volumes where the bass stays composed and textured. This isn’t a bass-head tuning—it prioritizes control and musicality over raw impact.

On James Blake’s “Limit To Your Love”, the deep sub-bass sweeps are audible and well-defined but not exaggerated. The Serene won’t rattle your skull, but it tracks the rumble with composure. Similarly, Infected Mushroom’s “Becoming Insane” shows the planar driver handling fast electronic bass with decent speed, though it never approaches the visceral punch you’d get from a more bass-forward headphone. Keep the volume sensible and the bass delivers body without turning muddy.

Note: I did find wearing glasses with the Serene meant I sacrificed the sub-bass a little. This will be obvious later in the measurements, but I think it’s worth noting if you wear glasses you probably won’t get any sub-bass.

Midrange

Vocals and instruments sit a touch back of neutral but remain smooth and fatigue-free. The polite upper-midrange trades bite and presence for long-term comfort, making this an ideal choice for extended listening sessions with warmer genres.

Norah Jones’ “Don’t Know Why” benefits from the relaxed presentation—her voice is intimate without edge, and the piano sits naturally in the mix. On The Black Keys’ “Lonely Boy”, Dan Auerbach’s vocals have grit and character without any harshness, and the raw, garage-rock energy comes through with warmth intact. Bruce Springsteen, Jason Isbell, and similar artists all sound inviting here.

Treble

Treble energy is subdued rather than sparkly. Cymbals, hi-hats, and upper harmonics are rendered safely with zero sibilance or spike. If you’re treble-sensitive or listen to brighter recordings, this tuning is genuinely friendly—though detail enthusiasts may find it a bit too polite.

AC/DC’s “Back in Black” puts cymbals in check—they’re present but never splash or fatigue. Daft Punk’s “Giorgio by Moroder” with its layered synths and hi-hats remains smooth and controlled throughout. The darker tilt means you won’t get that airy, extended shimmer, but you also won’t wince at poorly mastered tracks.

Soundstage & Imaging

As a closed-back, stage width is moderate but organized. Imaging is stable with a well-defined center, and instrument separation holds up at reasonable volumes. This isn’t a spacious, open-air presentation, but it conveys live performances with believable placement and coherence.

The Eagles’ “Hotel California (Hell Freezes Over)” maintains the live atmosphere with clear left-right guitar interplay and Don Henley anchored in the center. Eric Clapton’s “Unplugged” captures the intimate, acoustic setting convincingly—the soundstage doesn’t stretch wide, but it feels natural and unforced. At lower, “serene” volumes, it’s an easy, non-fatiguing listen that prioritizes musicality over analytical precision.

Distortion and Driver Crinkle

Normally, headphone distortion isn’t a show‑stopper for music listening, even if test tones can provoke it. With Serene, I did run into fairly bad audible bass distortion on tracks like James Blake’s “Limit To Your Love” at a reasonably loud setting, especially in the first day or so of listening.

Zeos mentions this in a short tip video and suggests opening the driver if you encounter it (his tutorial is here: https://www.youtube.com/watch?v=B2b8d3_cSKU).

For completeness, I did disassemble one side to inspect and re‑seat but left the other alone as I wanted to see if it really made a difference. As you can see the driver is tiny:

Here is the planar driver compared to the FiiO JT7:

And adding the FT1 Pro, the Serene looks even smaller:

But it is straightforward to open up, in the pictures above you will see the 3 external screws:

Here is a closer look at the 3.5mm connector:

This did not seem to make a difference the evening I did this but then the following morning I went for another walk with the Serene.

Walk test

While this test was mainly to check the isolation, as I mentioned earlier. I was sort of amazed as
the distortion largely disappeared after about 10 minutes of walking in the rather cold Autumn temperatures.

So, was this “atmospheric changes” that allowed the driver to tighten or did the driver warm up by being used fairly loudly for 10 minutes?

Note: I do not believe in “burn‑in” (beyond brain burn‑in), but this little experience did show a behavior that I managed to measure.

Here was the initial distortion I was seeing with the Serene:

And here was the distortion afterwards at roughly the same volume:

A few days later I also did a comparison measurement (as I was still hearing some distortion), this time I left the Serene on my measurement rig and measured first (Red), then played some loud music for 10 minutes and measured again (Green):

So I do feel the driver is a little problematic, but mostly at normal listening levels it won’t be a problem, but it definitely something to be aware of.

Specifications

Measurement note: my Luxsin X9 impedance meter read 60 Ω at the jack, not the stated 50 Ω, and the stated sensitivity values seem like they are incorrect, as I felt it did need some decent amount of power to open up.

Measurements

Let’s start with the frequency response: You can see:

1. Warmer midbass but nothing crazy
2. Darker treble

Here is the same measurment against Harman (but with the preference bounds set):

While there is sub-bass (the lower end of the preference bounds), it is that mid-bass that really stands out and I feel this will be what people either love or hate about this headphone.

But one issue I had was with the fit for my larger ears, as I mentioned above, it was a tight squeeze for my ears, but if I didn’t get a tight seal (for example, wearing glasses) the bass would be audibly much worse:

Distortion

As I mentioned earlier, after the driver “warms up” there is very little distortion:

Comparisons (FR overlays)

Here is a brief comparison with some other closed back headphones, the FiiO FT1, the Aune SR7000 (an excellent closed back that should get more recognition) and ZMF Bokeh Closed (review coming soon):

1. The Serere does have more rolled off sub-bass compared to the others
2. It has the most mid-bass
3. The Serene and the Aune share that dark treble tuning the others are brighter

Rating

I’m giving Serene a pragmatic 4 out of 5 — but with three conditions:

1. Listen at normal, “serene” levels where the tuning shines and the bass stays composed. And if you do listen louder give it time for the driver to warm up or you may get that driver issue.
2. Make sure the fit works for your ears; if you have large ears, the smallish cups may be a deal‑breaker. You probably won’t get the bass as you won’t get the seal.
3. Give it some decent desktop power or use a reasonable powerful portable source like the CrinEar Protocol Max (boost enabled) if you want to listen to music on the move.

For me personally, the earpads size is mostly the dealbreaker. While the earpads foam is amazing, I always felt my ears were being stuffed into the headphone so never quite as comfortable as I would like and especially compared to other closed backs in my collection. The tuning would not be my personal favourite in a closed back, but it is probably better than any of the Hifiman closed backs. And it is mostly easy to EQ should you want too.

But beyond these issues, at $150 (or $130 with voucher) this closed-back planar has a nice warm tuning that many will prefer for long sessions.

Conclusion

Serene is a serious interesting attempt to deliver a decent closed back planar at a great price, and even with some of the problems mentioned earlier, it is probably KiwiEars best headphone yet. It trades the Eris sparkle and bass hedonism for a warm, darker balance that flatters a lot of music and encourages you to listen at comfortable levels.

I did found the tuning was great for some tracks within my library, especially great for classic rock, Americana/folk, blues, and some live recordings; so if you listen at normal listening levels, have smaller ears, and like a warm dark leaning closed-back, then Serene should absolutely be on your shortlist.

The Serene finds a calmer Zen like groove and sticks with it.