Astell&Kern LUNA

Astell&Kern LUNA, planar driver hi-fi earphones

Following the AK ZERO1 and AK ZERO2, Astell&Kern completes its in-ear earphone series with a third model featuring noticeably different technical choices. Here, the Korean manufacturer entrusts sound reproduction to a single driver of a type rarely seen in the in-ear format: a 13 mm magnetic planar called Katabiki, developed with Japanese specialist MADOO. The housing is made of titanium and the cable is by Eletech, with final hand assembly in Japan.

Katabiki, a single-magnet micro-planar magnetic driver

LUNA is built around a 13 mm magnetic planar driver developed by Astell&Kern and MADOO, a Japanese workshop specializing in this field. Called Katabiki, meaning “unilateral echo” in Japanese, it departs from common planar drivers with symmetrical magnets: a single powerful magnet combined with a dual annular yoke drives an ultra-thin diaphragm on which an aluminum conductive circuit is printed. This structure is designed to provide rigidity that supports fast response while limiting moving mass. In listening, planar promises remain the priority: fast transients and fine resolution, with clear separation between sound layers.

Titanium shell and moon-inspired lines

The outer shell is made of titanium, a material chosen for its rigidity and neutral resonant behavior, which helps contain unwanted vibrations from the housing. Inside, the diaphragm chamber is CNC-machined from a block of aluminum, contributing to the geometric precision of the acoustic chamber. The outer curves, inspired by lunar shapes, also serve an ergonomic purpose: they follow the contours of the ear to allow extended wear without pronounced pressure points. Each pair is hand-assembled in Japan by artisans trained in in-ear earphone manufacturing.

Low impedance and high sensitivity

With an impedance of 5 Ω at 1 kHz and a sensitivity of 105 dB, LUNA belongs to the category of easy-to-drive earphones. This combination reduces dependence on a very powerful music player and allows pairing with the majority of hi-fi digital audio players on the market, whether balanced or unbalanced. However, the very low impedance requires a source with well-controlled output impedance to prevent the amplification chain from coloring the signal, which is generally the case with recent hi-fi digital audio players.

Eletech cable with silver-plated OCC and copper conductors

To connect the earphones to the source, Astell&Kern entrusted cable production to specialist Eletech. The conductor combines strands of pure OCC copper and strands of silver-plated OCC copper, two types of conductors often paired to combine clarity in the treble range with body in the low-midrange. On the earphone side, the connectors use the 0.78 mm two-pin format, common on high-end in-ear earphones, opening the way to replacement with a third-party cable or trying other terminations. The plug on the source side is a balanced 4.4 mm connector, a format that has become the standard on recent hi-fi digital audio players. The connector housings feature an aluminum finish matching the rest of the set.

Seven pairs of eartips and an Alcantara case

The box contains seven pairs of eartips in total. Three pairs of Baroque silicone eartips (S, M, L) serve as the default configuration. Three pairs of AET07 eartips (S, M, L), designed by Japanese manufacturer Acoustune, offer a different acoustic signature with an upper midrange that is often a little more open. One pair of memory foam eartips provides more pronounced passive isolation and a more enveloping fit. Everything is stored in an Alcantara carrying case, a material chosen for its durability and matte feel.

Technical Specifications

Overview

• LUNA, the third product in Astell&Kern’s IEM series, continues the brand’s philosophy in the pursuit of exemplary sound fidelity
• Designed based on the experience gained during the development of the AK ZERO1 and AK ZERO2
• Precise sound reproduction, enhanced spatial awareness, and improved tonal balance thanks to the 13 mm planar driver
• Authentic Astell&Kern sound signature

Driver

• Type: newly developed Katabiki unipolar micro-planar magnetic driver
• Configuration: 1 x 13 mm unipolar magnetic micro-planar driver
• Developed in collaboration with MADOO
• Design inspired by dynamic drivers, featuring a unique unipolar magnetic circuit and ultra-thin diaphragm

Acoustic Performance

• Impedance: 5 Ω at 1 kHz
• Sensitivity: 105 dB
• Low impedance and high sensitivity allow easy pairing with a wide range of portable audio sources
• Sophisticated single-driver acoustic design, meticulously tuned for spatial awareness, tonal balance, deep bass, and delicate highs across all music genres

Design and Materials

• CNC-machined aluminum diaphragm housing for durability, rigidity, and optimized acoustic performance
• Titanium shell for enhanced robustness
• Ergonomic and elegant design, inspired by the moon’s soft curves, for aesthetic sophistication and extended wearing comfort
• Hand-assembled by expert craftsmen, with precision quality control

Cable

• Premium Eletech Hi-Fi-grade silver-plated OCC and copper OCC cable
• Aluminum-finished connectors
• Plug: 2-pin, 4.4 mm
• Engineered for precise and detailed sound reproduction

Included Accessories

• LUNA earphones left / right
• Hi-Fi-grade silver-plated OCC and copper OCC cable (2-pin, 4.4 mm)
• 3 pairs of Baroque eartips (S / M / L)
• 1 pair of foam eartips (F)
• 3 pairs of AET07 eartips (S / M / L)
• 1 premium Alcantara carrying case

Manufacturing

• Made in Japan
• Handcrafted assembly with precision quality control