Astell&Kern has officially started shipping the LUNA IEMs—its second major announcement from High End Munich 2025, right behind the jaw-dropping (and bank account-draining) A&ultima SP4000 DAP. Priced at $2,700, the LUNA isn’t exactly budget gear, but it’s clear A&K isn’t playing in the shallow end of the pool.
The LUNA is the third model in the company’s in-ear lineup and builds on the groundwork laid by the AK ZERO1 and ZERO2. The headline this time? A 13mm planar driver, developed with MADOO, that goes by the name “Katabiki” — more on this below.
True to Astell&Kern’s core philosophy—uncompromising fidelity to the original recording—the LUNA aims to deliver a more natural and transparent listening experience. Whether it justifies the price tag is another story, but if you’re already eyeing the SP4000, chances are you’re not worried about the cost of admission.
Interestingly, according to eCoustics Headphone Editor, Will Jennings, the Katabiki’s ultra-low 5Ω impedance theoretically clashes with Astell&Kern’s flagship DAPs, whose output impedances hover around 0.7Ω—slightly above the ideal maximum of 0.625Ω for optimal pairing. This mismatch raises questions since A&K usually nails their specs, making us wonder if there’s some rounding in play or a deliberate design choice on the Luna’s output stage. We’re currently waiting on Astell&Kern for clarification, but for now, this quirk is worth keeping in mind when matching these IEMs with source gear.
LUNA-tic Engineering: Astell&Kern’s $2,700 IEM Aims for the Moon—Literally
The centerpiece here is the Katabiki (片響), which translates from Japanese as “one-sided echo.” This custom 13mm Unipolar Micro Planar Magnetic Driver was co-developed with MADOO, a company known for designing planar magnetic drivers for in-ear monitors both under their own brand and as an OEM/ODM for others. Partnering with Astell&Kern, MADOO was able to create a no-compromise micro-driver that exemplifies their technical expertise, aligned with A&K’s “Sound above all else” philosophy.
Unlike typical planar drivers that use bipolar magnetic circuits, the Katabiki employs a unipolar magnetic circuit, where the magnetic force is applied exclusively to the rear side of an ultra-thin diaphragm patterned with aluminum. This design eliminates the need for magnets or other components in front of the diaphragm, resulting in an unobstructed path between the driver face and the ear canal. The result is a driver with exceptionally fast transient response, high resolution, and a natural resonance that closely mimics the behavior of dynamic drivers, but with the advantages of planar magnetic technology.
The driver housing is CNC-machined from aluminum for maximum rigidity, and every single element—from the dual ring-shaped yoke to the resonance-optimized internal structure—is tuned for performance. Astell&Kern didn’t just build this to sound good—they built it to remind you why they’re in a league of their own.
And that sonic precision carries through. LUNA’s titanium shell isn’t just for looks. It enhances durability and is shaped for maximum comfort. The sound profile hits all the sweet spots: deep, controlled bass and delicate, textured highs that remain clean across genres.
It doesn’t stop at the hardware. The cable, developed by Eletech, combines silver-coated OCC with pure copper OCC conductors to preserve detail and dynamic range. Every connector is machined from aluminum—because, of course it is—and the final assembly takes place in Japan under the hands of skilled artisans. This isn’t mass production. It’s IEM haute couture.
Aesthetically, LUNA leans into the celestial metaphor with flowing curves and a cool metallic finish that feel high-end without tipping into sci-fi cosplay. The design prioritizes acoustic flow and in-ear stability, so even if you’re wearing a $2,700 IEM, you won’t feel like it’s trying to launch from your ears mid-track.
In short, LUNA is a masterclass in obsessive audio craftsmanship—and one that won’t let you forget it.
What Do I Get for $2,700?
Aside from a serious dent in your wallet and bragging rights at your next audiophile meet-up, Astell&Kern’s LUNA includes a premium set of accessories worthy of its flagship status:
- LUNA IEMs – Precision-crafted titanium shells housing the custom Katabiki planar magnetic drivers.
- Hi-Fi Cable by Eletech – A silver-coated OCC and copper OCC cable with a balanced 4.4mm plug, because anything less would be beneath LUNA’s pay grade.
- Ear Tips Galore – Three pairs of Baroque tips (S/M/L), three pairs of AET07 tips (S/M/L), and one pair of foam tips for those who like their fit extra snug.
- Alcantara Carrying Case – Soft, durable, and way too nice to toss in your glove box.
Astell&Kern LUNA – Tech Specs
- Model: LUNA
- Driver: One 13mm Unipolar Micro Planar Magnetic Driver
- Design: Closed-back IEM with 2-pin connector
- Housing Material: Precision-machined Titanium
- Frequency Response: 20Hz – 30kHz (wide enough to hear ghosts)
- Sensitivity (SPL): 105dB @ 1kHz (1mW) – easy to drive, but give it some headroom
- Impedance: 5Ω @ 1kHz – extremely low; pairs well with high-quality, low-output impedance sources
- Total Harmonic Distortion (THD): 1% @ 1kHz – clean enough for critical listening
The Bottom Line
The Katabiki-driven IEMs from Astell&Kern and MADOO deliver cutting-edge planar magnetic technology in a compact 13mm driver featuring a unique unipolar magnetic circuit. This design offers lightning-fast response, high resolution, and natural resonance with no obstructions between driver and ear—pushing in-ear audio performance to new heights. All that tech comes at a premium, reflecting Astell&Kern’s “Sound above all else” mandate, making these IEMs a serious investment for audiophiles who demand the best without compromise.
For more information: astellnkern.com
Where to buy: $2,700 at Bloom Audio
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Billy Yelchin
June 11, 2025 at 11:55 am
$2,700 for universal IEMs? Ouch.
That’s a huge ask, even if they’re exceptionally great.
Ian White
June 11, 2025 at 3:46 pm
Billy,
Yes, that’s a lot of money for universal IEMs, but there is a market for it.
IW