Kiwi Ears Aether

Kiwi Ears Aether



- For the watchers -

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Introduction & Disclaimer

Every few years, a new technology, piece of equipment, or device appears within the high-end audio space that shakes things up and leaves a watershed moment on headphone history.
In 1979 it was the STAX SR-Lamdba; the first headphone to ever offer something actually resembling linear tonal response.
In 1989, Sony proved that high end audio wasn't limited to open back design with the very much closed-back MDR-R10.
In 1991, Sennheiser established the legendary comfortable middle-ground benchmark and the foundation of the HD600 series, the HD580 Precision.

Now, I don't have the clairvoyance to predict whether the Aether will go down in history, spawn a legacy or change the audio industry forever, but I think it damn well should.
This may well be the most important IEM yet made.

This sample was sent by Kiwi Ears for the purpose of this review.
Website + Specs - https://kiwiears.com/products/kiwi-ears-aether

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Build, Design & Aesthetics

Kiwi Ears has opted for a more rounded design for the 3D-printed resin shells of the Aether, adorned with milled aluminium and glittery resin faceplates.
The housings feature metal nozzles (6.4mm), one ear-side vent, and 3 forward facing vents. Despite the extra venting, I didn't notice any interference from wind, but neither did I find these any less isolating than the average IEM, which was at least a welcome relief.
I didn't have any problem with the ergonomics, however they don't provide the most snug fit either. I think as long as you're not adverse to larger housings, these should provide a relatively easy wearing experience.


Housed within the shells are one of the largest planar drivers ever produced for a closed-type in ear monitor out of China, at 15.3mm.
They are also sensitive enough to be driven directly from a smartphone without the assistance of a dongle DAC amplifier.

The cable is fantastic.
It's pliable, doesn't retain memory and fits the aesthetic.

It’s also thicker than average, so it doesn’t tangle as easily as even the KE4 cable.
The new and improved carry case arrives in a timely manner for the first new IEMs of 2025 and the cherry on top is the inclusion of 3 different sets of tips to ensure the best fit is found.

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The Sound

So how does it sound?
There is only one way to describe the way my ears hear this IEM.

It is a reference model.

I hate to use such an overly abused term, but every so often, it's important to re-establish personal or public benchmarks that the masses vastly agree upon.
Sometimes there are headphones that absolutely deserve such attention but simply fall out of the mainstream due to lack of interest, bad marketing or one bad review from a prolific journalist.
I hope this won't be one such case, as for the first time in my life I find myself listening to an In Ear Monitor that not only presents audio without any one singular frequency or tonal band reaching out for attention or shying away, but does so without making significant compromise.



It feels like for once, the marketing team actually didn’t lie.
This is what Kiwi Ears had to say about the Aether - “Its studio-tuned sound signature provides a clean sub-bass response, flat midrange, and a natural treble peak for clear, balanced audio.”
I can only fully agree.

For lack of a better word, the Aether sounds neutral, but not in the way the AKG K612 Pro or Hifiman Susvara sounds neutral and sucks all the joy out of the music.
The Aether serves up every single part of the music on equal terms with just a hint of smoothness and an uncommonly large soundstage.
It just sounds right.


(measured on miniDSP EARS, so treble is unnaturally emphasised in the graph)

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Comparisons

Kiwi Ears KE4
The darling of the so-called meta-tuning pales against the uncontaminated purity reproduced by the Aether. The upper mid-range and treble particularly suffers from some unwanted tonal characteristics that some might describe as BA timbre, with a slightly plastic quality.


Kiwi Ears Orchestra Lite
The Orchestra Lite continues to wow me with it’s slightly holographic imaging and seductively hyper-realistic presentation of midrange, but we know it’s not a reference tuning.
The Aether more than confirms this.


Hifiman HE-500
The Aether reminds me most of the qualities I enjoy with my personal reference headphone, a modified Hifiman HE-500.
In fact switching between the two, I detect only an incremental increase in warmth in my HE-500, which I should mention is also modified, so it is more linear, a touch warmer and with smoother treble than a stock HE-500.
The uncanniness of overall timbre and tonality between these two is ridiculous, with the Aether falling only slightly behind, where treble sounds like cymbals are incrementally darker and weightier than the HE-500.

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Conclusions
In a time where truly high-end personal audio has never been so competitive, expensive, and littered with some quite frankly laughably bad offerings, the Kiwi Ears Aether is an oasis of sanity.

At $169 this is truly the first ‘people's reference IEM’ not hindered by poor build quality, awkward design decisions or restricted imaging and soundstage, and I believe it will become a benchmark for many IEM enthusiasts.



I really wonder if the big companies are ever going to respond, because the Chinese IEM industry overtook the consumer portion around 15 years ago and have been doing nothing but sprinting ahead ever since and now it seems they can’t keep up.

As a final footnote, I feel like I need to add that these are just my opinions and you don't have to agree with them.
There are also people out there who actually enjoy the DT990 Pro and the B+W P9, so while enjoyers of these obviously inferior headphones () might not quite be the Aether's target audience, anyone who appreciates the kind of truly rare neutral tunings offered by a select few high-end planars, a handful of electrostatics and even fewer dynamic headphones, then the Aether should be one for serious consideration at any starting budget.

The Aether receives my absolute fullest recommendation.

Kiwi Ears Aether Review: Next Plane of Existence​

Kiwi Ears Raises the Bar for… Everyone​

Kiwi Ears is the in-house brand for popular ChiFi (Chinese HiFi) retailer Linsoul. They’ve released a lot of IEMs since inception, many of which have become well-known crowd-favorites in the HiFi community. They were among the first on the scene to build planar-driver hybrid IEMs, and while those products had some room for improvement, that didn’t dissuade Kiwi Ears from continuing to explore the technology. Today we’re taking a look at Kiwi Ears’ newest and most robust planar-driver IEM. Featuring a massive 15.3mm planar driver and promising uncompromising studio-grade performance, the Aether has caught the attention of a lot of folks. But, does it perform in line with its promises? Let’s find out!

You can find the Aether for sale at Linsoul for $170.

About My Preferences: This review is a subjective assessment and is therefore tinged by my personal preferences. While I try to mitigate this as much as possible during my review process, I’d be lying if I said my biases are completely erased. So for you, my readers, keep this in mind:

• My ideal sound signature would be one with competent sub-bass, a textured mid-bass, a slightly warm midrange, and an extended treble.
• I have mild treble sensitivity.

Testing equipment and standards can be found here.

Tech Specs​

• Driver: 15.3mm neodynium planar driver
• Cable: 0.78mm detachable w/ 3.5mm termination
• Impedance: 14 ohms
• Sensitivity: 105db SPL/mW
• Frequency Response: 20Hz-20KHz

Sound Signature​

Sonic Overview:​

The Aether features open, airy, reference-style tuning. Its treble is well-extended and organic. Its midrange is neutral, with slight emphasis in the 2–3KHz range to bring out instrumental and vocal details. Its bass is extended, though not emphasized much. There’s a slight 1–2db lift in the mid-bass that provides solid lower-register articulation that carries out to the 20Hz range. The Aether’s studio-grade tuning allows it to express a wide soundstage with excellent depth and laying. Its new 15.3mm driver delivers excellent planar-driver timbre with all of the usual psycho-acoustic properties you’d associate with a high-quality planar driver.

Sonic Breakdown:​

Treble: Songs used: In One Ear, Midnight City, Outlands, Satisfy, Little One, Show Me How To Live (Live at the Quart Festival), Bittersweet Symphony

The Aether is one of those IEMs that, for most people, will make you say “wow, I’ve never heard that in this song before!”. That’s in no small part a feature of the Aether’s incredibly transparent and articulate treble. The Aether’s upper-register is genuinely reminiscent of full-sized planar headphones in that its spares no effort in providing maximum speed and near-flawless control. It isn’t just detailed, either. The Aether’s treble is even and organic, almost never sounding too hot, sharp, or over-blown.

This isn’t all smoke and hype — you can look into my past writing to see that I rarely get swept up in marketing-driven excitement. It doesn’t really matter what track you throw at the Aether as it will resolve it well. Tracks like Bittersweet Symphony represent but a trivial challenge for the Aether’s massive drivers. The song’s beautiful cacophony of string instrumentation and percussion is carefully, surgically even, layered by the Aether. Gone is the impenetrable wall of treble noise found with lesser IEMs — instead listeners are presented with a proper symphony.

The lonely electric synth lines of Midnight City cut through its bleak, dark background with precision and intent. The Aether’s incredible attack and decay speeds complement the echo-filled vibes of M83’s performance, truly delivering a faithful reproduction of their legendary track. This song is one that is easy to get wrong, and many planar IEMs I’ve tested sounded sharp at the edges of the synth effects. The Aether is free from sharpness and hotness which is a boon to treble-sensitive listeners like me.

Midrange: Songs used: Flagpole Sitta, Jacked Up, I Am The Highway, Dreams, Too Close, Little Black Submarines, Bohemian Rhapsody, Cash Machine, Chasm

As with its treble, the Aether’s midrange is incredibly detailed and evenly-toned. This is an IEM with a truly “perceived neutral” midrange that refuses to play favorites. Jacked Up’s wide assortment of instruments do a good job of exercising the Aether’s midrange muscles. The track’s vocals are highly intelligible, with almost every inflection in delivery captured by the Aether’s drivers. The tracks two pianos clamor together in the background, each sitting in their own distinct spot on the sound stage. Each note springs into existence with clarity and precision and fades out organically. Percussion is likewise rendered impressively; drum slams and kicks are remarkably distinct and well-bodied.

I had anticipated that the Aether’s reference-style tuning would make Flagpole Sitta and its dry-mastered ilk a boring listen, but that doesn’t seem to be the case. The Aether so rigorously captures detail that the track becomes rich in tone and texture, not simple warmth. This style-agnostic prowess gives the Aether a special place in my rotation and is a major part of why I like it so much.

Bass: Songs used: Moth, Gold Dust, In For The Kill (Skream Remix), War Pigs (Celldweller Remix), Feeling Like The End

The Aether’s bass is slightly emphasized, with a mild 1–2db lift over its lower midrange. This gives the Aether a solid lower register with the occasional capacity for punch and rumble. For a reference-tuned IEM, this quantity of bass is plenty. It adds much needed weight and substance to tracks and does a great job at minimizing dryness. Even electronic music is well-served by this tuning. Sure, it might be more fun to crank the bass, but the Aether doesn’t sound flat nor anemic. From the perspective of a critical listener, the Aether does bass extraordinarily well, even for fat dubstep drops.

I often write about bass “shape” and “control”. These are concepts that ultimately boil down to how precisely the IEMs driver(s) can produce bass and how well the acoustic cavity minimizes distortion and decay. The Aether’s bass is extremely quick and precise. Its healthy portioning combined with its speed makes it, at this price, uniquely adept at resolving subtle bass queues. Its precision allows it render nearly-tactile effects. For example, the Aether resolves Joji’s bass element in Feeling Like The End at 0:52 with a seemingly physical exhale. This is extremely subtle effect that is easy to miss outside of critical listening, but wow, I wasn’t anticipating such an affordable IEM to possess this level of technical ability. In fact, none of my other IEMs could replicate this sensation.

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Packaging / Unboxing​

Kiwi Ears usually sticks to fairly basic packaging for their IEMs, so I was pleasantly surprised to find that the Aether’s has a more-premium look and feel. Each surface below the outer-sheathe makes excellent use of a semi-textured, partially-reflective silver cardboard. It does a good job of emulating the look of brushed aluminum/stainless steel.

Build​

Construction Quality​

The faceplates on the Aether are down-right gorgeous. Every inch of the Aether’s shells, apart from its nozzles is made out of plastic — but that doesn’t make it look or feel “un-premium”.



The Aether’s nozzles are, mercifully, made out of metal. They are a little above-average in depth and size. Below the nozzle’s lip sits a metal perforated debris filter. The filter sits securely and looks to be capable of repelling most dust, dirt, and viscous fluids. The top-face of the Aether’s shells houses a the IEMs 2-pin sockets and primary vent. Be aware that the primary vent is large and can very easily accumulate finger/skin oils, dirt, or (rain) water.



I was hoping that the Aether would come with a cable similar to the Orchestra Lite, but alas, we get a simple, but well-designed, black plastic cable. It features 0.78mm 2-pin connectors housed in a standard black shell, a black-plastic Y-splitter, and a 3.5mm termination housed in a black metal shell.

Power​

The Aether’s impedance is rated at a shockingly low 14ohms. That puts its squarely in “easy to drive” territory, especially when combined with its incredibly reasonable sensitivity. Apple’s USB-C adapter is more that capable of driving the Aether at, or near, full quality. Meze’s Alba dongle is likewise plenty powerful. The Aether had zero hiss and a very dark noise floor on all sources I tested, so even pedestrian 3.5mm sources should work well.

Comfort​

Disclaimer: comfort is a highly individual metric — no two people will have the same experience.

By virtue of the Aether’s massive planar driver, it also has large shells. They’re of average ergonomic design and not too hard for me to wear for extended listening sessions. I highly recommend experimenting with ear variety of eartip, and perhaps some aftermarket ones, to get as strong of a passive seal as possible.

Accessories​

Inside the box you’ll find:

• 1x semi-hard carrying case
• 1x 3.5mm cable
• 9x pairs of silicone eartips

The eartips that Kiwi Ears include in the box are serviceable, but not great. In fact, one eartip I tried to apply actually tore while placing it on the Aether’s nozzle. Thankfully I have plenty of spares, but its an irritating experience nonetheless.

The Aether’s case is fairly standard, though it is larger than the one that came with my previous Kiwi Ears IEMs by a smidge. A slightly roomier case would have been great considering I always carry the Aether with a USB-C adapter.

Comparisons​

1: NFAcous NM20 ($120)

The NM20 is another “reference-style” IEM, though it features a single dynamic driver instead of a planar driver. It also comes in at nearly $50 cheaper, making it noticeably more affordable. The NM20 has smaller shells, a better-looking and feeling cable, and a better-fitting case. The Aether’s ergonomics may be worse, but it posses undeniably superior technical capabilities. Its soundstage is wider, treble more extended, bass more precise; there’s a laundry list of performance advantages.

From a purely analytical perspective, the Aether is the better tool for mastering, studio work, etc. That said, the NM20’s bassier, more V-shaped sound signature may appeal to those who want a somewhat more-mainstream tuning. Its superior ergonomics may also sway an potential buyer, particularly if he/she is sensitive to the bump in price for the Aether.

2: BQEYZ Frost ($180)

BQEYZ’s Frost is a very unique IEM that brings non-standard tuning to the table. It is slightly more expensive than the Aether and packs a better cable, aluminum + glass shells, and a larger carrying case. Its ergonomics are similar to the Aether’s, though the added weight of aluminum does tire the back of the ear faster. BQEYZ’s included eartips are more comfortable for me and seal better than the standard Kiwi Ears assortment that was included with the Aether.

Sound-wise, both IEMs possess serious technical chops. The Frost does a great job at unifying its flat, warm, midrange with a sparkly and robust treble. It has an intensely organic lower register that is slightly more emphasized than the Aether. The Aether, by comparison, is a cooler, more analytical IEM. Its treble is more even and further extended, while its midrange is far more neutral and lacking the Frost’s signature warmth. In terms of sound staging, both IEMs are great performers with the Aether pulling ahead in both depth and width.

Conclusion​

The Aether raises the bar for the entire IEM industry. It represents a tectonic shift in what consumers can expect in both tonal purity and technical prowess per dollar. The fact that Kiwi Ears is selling the Aether for a mere $170 should do well to light a fire under both Eastern and Western brands. The Aether’s capacity to resolve detail eclipses many much more expensive IEMs both old and new alike. While not everyone wants an analytical IEM, those who are willing to give reference-style tuning simply cannot go wrong with the Aether.

Who This is For​

• Audiophiles who want reference-grade sound
• Listeners who enjoy neutral sound signatures
• Planar-driver enthusiasts

Who This isn’t For​

• Bassheads
• Listeners with small ears
• Those who crave warm sound signatures

As always, happy listening!