Today’s feature is Kurt’s review of the Kiwi Ears Aether, a new 15.3mm single planar driver universal in-ear monitor currently priced at $169.99.
Disclaimer: This sample was sent in exchange for my honest opinion. Headfonics is an independent website with no affiliate links or services. I thank Linsoul and Kiwi Ears for their support.
Click here to read up on Kiwi Ears gear previously reviewed on Headfonics.
This article follows our latest scoring guidelines, which you can read in more detail here.
Kiwi Ears made a name for themselves with popular releases such as the Quartet and Orchestra, the latter of which gave the Moondrop Blessing 2 a run for its money in the midrange market.
Since then, they’ve expanded into headphones, TWS, and dongles while continuing to release great-value and unique IEMs such as the KE4.
They’ve also experimented with unconventional configurations, like the Kiwi Ears Quintet, with a dynamic driver, BA, planar, and PZT driver setup.
Now with the $169.99 Aether, which features a massive 15.3mm planar driver, the largest in an IEM to date, can Kiwi Ears raise the bar for planar IEMs? I found out in my full review below.
Features
The Kiwi Ears Aether features a massive 15.3mm planar driver, currently the largest in any planar IEM, paired with multi-layered N52 neodymium magnets.
Stacking multiple N52 magnets gives it the capabilities needed to surpass typical 12mm and 14mm planar drivers in clarity and control.
The larger surface area helps compensate for the bass weaknesses usually found in planar IEMs, delivering stronger rumbles and better punchiness.
Kiwi Ears also designed a larger acoustic chamber around the driver to enhance imaging and expand the soundstage.
Alongside the larger chamber design, the Aether uses an improved ventilation system aimed at recreating the spaciousness of open-back headphones. It follows Kiwi Ears’ signature tuning approach, which targets natural tonality and accurate timbre for an immersive listening experience.
Design
The Kiwi Ears Aether features a smooth black acrylic shell with a silver, ridged frame that wraps the faceplate like a polished border. The shell keeps things minimal with no flashy details and is fully opaque, hiding the massive 15.3mm planar driver from view.
The silver ridge surrounding the faceplate resembles the dial of a wristwatch, adding a refined contrast to the plain black shell. Despite its layered appearance, the frame is smooth to the touch with no sharp corners to compromise comfort.
All the eye-catching detail lives in the faceplate, which resembles a rough cut of obsidian, as its jagged ridges mimic the fractured edge of stone. When hit with light, subtle rainbow glimmers and sparkles scatter across the obsidian-like surface, giving it a unique cosmic shimmer.
A silver “Kiwi Ears” logo sits right at the center, layered over a faint starburst design and sealed beneath a glossy layer of acrylic. It protects the design while creating a sleek, glassy effect that gives the faceplate a premium feel and polish.
Three small vents sit neatly beside the 0.78mm 2-pin connectors for pressure relief, with a fourth on the inner side of the shell. The nozzles are surprisingly short, but they have a well-defined lip and a mesh grill to secure ear tips and keep debris out.
Comfort & Isolation
The Kiwi Ears Aether is easily the largest planar IEM I’ve seen, yet it manages to stay comfortable without feeling bulky. Its smooth, corner-free design helps create a good seal that prevents bass leakage and improves overall immersion.
I’ve never had issues with IEM fit, but the Aether’s wider shell might stretch smaller ears more than expected. For those with larger ears, it fits nicely and rests flush without causing any discomfort.
Extended listening is easy with the Aether, thanks to the well-placed vents that relieve pressure. Its lightweight construction also helps, as it never feels like a heavy presence on the ear despite the size.
The short nozzle helps in getting a deeper fit and also keeps the body from protruding too far. However, lying down with it isn’t ideal since its large shape is still noticeable when pressed against a surface.
Isolation is about average, as nearby conversations can still be heard even with music playing. Fan noises and ambient sounds are reduced, but voices still make it through.
Ear Tips
The Kiwi Ears Aether doesn’t offer much variety when it comes to the tips. All of them share the same soft silicone texture and balanced bore design, differing only in color.
You get three sets in semi-transparent white, translucent black, and translucent black with a red stem. None of them change the sound, keeping the tuning as intended without boosting or dulling any frequencies.
Comfort is perfectly fine for short listening sessions, with no irritation or issues at first. Unfortunately, that changes over time as the dry silicone texture becomes itchy during longer use.
Stock Cable
Unlike the stylish faceplate, the Kiwi Ears Aether’s stock cable looks rather plain, with a simple black finish and no standout design elements. It’s thin and feels a bit low quality, but it’s lightweight and easy to handle.
There’s no Kiwi Ears branding or logo anywhere on the cable, giving it a generic feel. The only distinguishing features are the red ring on the right connector and the transparent plastic on the left to indicate channel sides.
It uses a standard 3.5mm termination, which feels limiting for an IEM with a large planar driver that could benefit from a balanced setup. Unfortunately, the cable isn’t modular either, leaving no option for 4.4mm, 2.5mm, or USB-C swaps without upgrading separately.
Packaging & Accessories
The front of the box displays the Kiwi Ears Aether with its name below, the Kiwi Ears logo in the top right, and other information printed over a gradient pink-and-white background with a snowflake pattern. The back keeps the same theme with the snowflakes, but lists certifications and brand labels.
Technical specifications like driver type, sensitivity, and impedance are printed on the top of the box, while the bottom highlights the Aether’s massive 15.3mm planar driver. Lifting the lid reveals a clean, white, sandstone-like inner box with the Kiwi Ears logo engraved in the center.
Sliding that box up unveils a folder-style inner compartment in the same textured finish, which houses the user manual. Beneath it is the Aether itself secured in a foam cutout alongside two accessory boxes, one larger and one smaller.
Removing these compartments was tricky, as there were barely any gaps to grip. Taking out the Aether required a firm pull since there are no gaps in the foam, leaving no room to lift it gently.
The large accessory box had cutouts to help with removal, but pressing too hard felt like it might tear the thinner middle panel. Inside was a branded carrying pouch containing the cable, tucked neatly inside.
The smaller box held the three sets of silicone ear tips in separate color-coded pairs. While everything essential was included, the basic cable and tips didn’t quite match the premium expectation set by the IEM itself.
Sound Impressions
The following sound impressions of the Kiwi Ears Aether were completed using the Colorfly CDA-M2, the Heartfield R1, and the FiiO JA11 as my main sources and amps.
Bass
I expected the Kiwi Ears Aether’s 15.3mm driver to enhance its treble, but instead it completely reshaped how I think about planar bass. Kiwi Ears delivered something special here, offering possibly the cleanest and best-controlled bass I’ve heard from a planar IEM.
The bass retains the quick planar speed, yet finally delivers genuine impact behind every note. Its subbass provides a clear, well-felt rumble that doesn’t just support the music but actively adds depth and presence.
The real surprise comes in the midbass, as the Aether delivers punches that are rhythmic and engaging. It doesn’t approach basshead levels, but its precise, impactful hits breathe life into every track.
What truly impresses me is the exceptional bass control, never allowing any muddiness or bloat. There’s zero bleed into the midrange, ensuring the entire low-end remains tight and refined.
Bass guitars especially benefit from this clarity, each pluck coming through cleanly with well-defined depth. It never sounds blunted or artificial, consistently maintaining a natural and realistic tone.
Mids
The midrange of the Kiwi Ears Aether is excellent overall, but it has some minor issues that are easy to hear. Vocals lack a touch of warmth, coming off slightly thinner than I’d like, though this doesn’t significantly hurt the natural timbre.
Planar timbre is present but minimal, never dipping into metallic or overly artificial territory. Female vocals could benefit from extra note weight for more body, while male vocals feel more naturally balanced and satisfying.
The Aether is one of the rare planar IEMs that avoid sounding overly sharp or harsh. Vocals remain realistic and balanced, comfortably placed in the mix without being overly forward or recessed.
What stands out most is the note definition, clearly highlighting subtle backing vocals and buried instrumentals. Instruments such as guitars and pianos have noticeable texture and presence, enriching the overall experience.
Instead of leaning towards an analytical tuning, the Aether delivers a smooth, musical presentation. Its tonality strikes a neutral balance, never feeling overly warm or too dark, making it a versatile and pleasant listen.
Treble
Surprisingly, the treble isn’t the standout feature of the Kiwi Ears Aether, as the bass manages to outshine it. Still, it delivers the quality highs you expect from a planar, without the usual bright peaks or harsh sibilance.
Its treble extension is airy and smooth, maintaining clarity without overdoing the sparkle or energy. This careful tuning ensures comfort even for treble-sensitive listeners, as it avoids exaggerated brightness.
Listening at higher volumes might bring some fatigue, but at normal levels, the treble strikes a pleasant balance between lively and relaxed. Sibilance is impressively controlled, matching the refinement seen in the bass.
Detail retrieval is exceptional, effortlessly highlighting subtle sounds within the music. Small details like guitar strings being plucked or the movement of a violin bow become distinctly audible, adding a layer of depth.
The refinement is particularly evident with percussion instruments such as cymbals and hi-hats. They retain their natural shimmer and decay without sounding artificially boosted or unnatural.
Staging & Dynamics
The soundstage of the Kiwi Ears Aether offers average width and height, but it compensates impressively with precise imaging. Despite the limited space, the imaging makes excellent use of what’s available, creating an engaging and immersive listening experience.
Thanks to the excellent clarity and note definition in the midrange and treble, vocals and instruments are easily distinguishable. This ensures superb layering and separation, preventing the audio from ever becoming cluttered or confusing.
Height in the soundstage is restricted, but there’s enough depth to clearly distinguish sounds placed forward or behind. The imaging also allows slight vertical positioning of sounds, although it still feels somewhat constrained.
Different sounds smoothly pan from side to side with impressive accuracy, creating the holographic listening experience that Kiwi Ears aimed for. This exceptional imaging is likely enhanced by the new vented design, giving music a lively and immersive quality.
Dynamics, however, aren’t particularly strong, as the Aether noticeably benefits from increased volume and more power. This becomes most evident in the midrange, where higher volume brings out noticeably improved presence and definition.
Click on page 2 below for my recommended pairings and selected comparisons.
