Since the birth of the brand, Astell&Kern has launched a series of classic earphone products including T8iE, T9iE and Layla AION. But without exception, these models are jointly launched by Astell&Kern and Beyerdynamic or JH Audio. Finally, audiophiles ushered in the first headphone developed and marketed by Astell&Kern – AK ZERO1.

Appearance Design

AK ZERO1 follows Astell&Kern’s iconic light and shadow cutting design concept. The diagonal lines on the cavity panel allow earphone to reflect different refractions under the light, conveying a restrained and extraordinary visual experience. We have seen more or less iconic elements of the brand in past Astell&Kern headphone products. But I personally guess that most works just incorporate Astell&Kern engineers’ understanding of sound, so that these earphones can bring perfect sound performance when paired with Astell&Kern players. The AK ZERO1 is 100% independently developed and designed by Astell&Kern, and has absolute autonomy in the appearance, internal design and sound control of the product.

The Astell&Kern ZERO1 earphone shell is made of CNC aluminum alloy, with a low-key matte silver back panel and a delicate black frosted cavity. The classic and elegant silver and black color scheme and the delicate matte treatment process give people a tactile and visual feeling of collision between metal and plastic materials, but the earphone does use 100% metal casing.

With silver-plated OFC wire, the connector and splitter have a good consistency with earphone in design. In addition, you can also buy the 4.4MM balance upgrade line separately. Astell&Kern pays great attention to every detail of the product. The data cables and plugs included with the player are carefully designed. Another example is the TYPE-C interface of AK PEE51, which also adopts the iconic light and shadow design. These visually unifying details give a product a refined and complete visual experience. It is precisely because of 100% independent research and development that it is possible to make AK ZERO1 more perfect in these details.

Internal Structure

Astell&Kern ZERO1 is an “armature+dynamic+planar” in-ear earbuds. The earphones are equipped with a 5.6mm dynamic driver and two custom armature drivers.

I believe that some audiophiles have also come into contact with some earbuds that use small planar drivers. Such as UM ME.1, AUDEZE Euclid, iSINE10, iSINE20, etc. The driver characteristics of this type of earphones have achieved its extraordinary detail performance ability and transient response, and it also has outstanding performance capabilities for elements such as vocals.

Unlike these earphones, Astell&Kern used a custom micro rectangular planar dynamic driver for the first time on ZERO1. The driver has excellent high-fidelity characteristics. At the same time, because of its small size, it can be easily installed closer to the conduit, which greatly reduces distortion during sound transmission and preserves the details in the music. In addition, the driver uses a precise metal film design, and can bring a very ideal balance.

After thorough research and understanding of the parameters and characteristics of each driver, with the help of precise 3D printing technology, the engineer designed a set of air resonance components for the AK ZERO1, so that the sound between each unit can reach a perfect balance. Tuning is performed by controlling and calculating the air flow in the casing to ensure that the driver is stably fixed in the casing, and at the same time, it can also eliminate the influence of undesired resonance, ensuring that the sound of the AK ZERO1 can be perfectly played.

Sound Description of Astell&Kern ZERO1

Astell&Kern ZERO1 is an earbuds that allows people to relive the essence of sound. It has a high degree of sound reproduction, excellent detail and a naturally balanced vocabulary. Its sound is neutral and natural, with almost no coloration, but the timbre is not dry and cold, and it can show rich and delicate layers and emotions for vocals and instrumental music.

The AK ZERO1’s low-frequency quantity control is just right, and it doesn’t give too much sound to the low-frequency. The sense of hearing and sound quality are somewhat similar to the qdc V3 II. Bring it to listen to rock music, the accompaniment is strong and powerful without dragging, violent and fast. Perhaps we can’t find a well-rendered reverb, or a rich and exciting quantity in the Astell&Kern ZERO1. But when we listen to electronic music and rock music, we can feel the passion and power of music. I think it is very rare to have such a performance after balance and trade-offs. The details and emotional characterization of instruments such as big bass and bass saxophone are also in place. I can’t say full marks, but I really can’t pick out any shortcomings.

The uncolored sound style of SP2000T OP mode is more likely to reflect the quality of the earphone itself. In this mode, the vocals of AK ZERO1 are delicate and timeless, and can be restored almost naturally. In Zhao Yiran’s “Unbearable Loneliness”, AK ZERO1 showed the atmosphere of the scene in a real and flawless manner, and the guitar sound was mellow and delicate, which restored the scene very real. Astell&Kern ZERO1 takes into account the indicators of cohesion, thickness and transient, and controls the sound very well, which also gives the headphones “compatibility” for different voices of different genders.

In addition, as a multi-driver earphone, the vocal positioning of AK ZERO1 is very scientific, and there are almost no shortcomings in connection. We can feel the smooth and natural transitions and the integrity of the sound in it, and its detailed description of the sound always reminds me of the T8iE/T9iE. As a product completely independently designed and developed by Astell&Kern, AK ZERO1 can better reflect Astell&Kern’s understanding and balance of sound.

Excellent high frequency extension, slim and clear. In SP2000T OP mode, listening to Salvatore Accardo’s 24 Paganini songs can bring people a gorgeous and elegant listening enjoyment. AK ZERO1 has perfect musical lines, concentrated but not mellow beauty, and the violin’s bowing performance is agile and free and easy. Overall, the Astell&Kern ZERO1’s high-frequency details are very rich and not hollow and harsh. With the 4.4MM official upgrade cable, it can bring unconventional and scientific sound field and presence. The separation and detail are impressive when listening to large-scale chamber music.

Summary

The appearance of Astell&Kern ZERO1 is not too stunning, but everyone can recognize its iconic light and shadow cutting design elements at a glance. As an earphone 100% independently developed by AK, engineers have more room for freedom of expression in all aspects. In the past few years, Astell&Kern headphones have been cooperating with major brands and jointly launched many products that represent the characteristics of AK tuning.

In the process, Astell&Kern has accumulated rich experience in headphone production and tuning, and is able to handle multi-driver matching and sound characteristics with ease. From it, we can see that Astell&Kern pursues the concept of the highest sound reproduction and highest quality, and engineers strive to create the most natural and true sound quality. The sound field and positioning are scientifically correct, and the frequency distribution, sound thickness and timbre have an excellent balance.