64 Audio A6t

The design of the cable on the A6t features a gold plated 3.5mm right angle connector. The detachable twisted cable can be safely placed over the ears. The models in the Allround series are specifically designed to fit each individual buyer’s ears. A visit to a hearing specialist might be costly but it is obligatory in order to have an impression made of the user’s ears. A precisely fitted earpiece made of anti-allergic acrylic is then created with the help of 3D scanners and 3D printing. There is a wide range of colours and designs to choose from so that the earpiece can be adapted exactly to the user’s wishes and can be made to be as visually unobtrusive as possible with a highly accurate and secure fit. The average time from receipt of the ear impression by the sales department to delivery is three to four weeks. The A6t also comes with a robust plastic transport case, a cleaning tool and a clip for attaching cables.

As a professional and quite high-priced system, the A6t relies on six balanced-armature drivers that share the frequency spectrum, using a passive integrated crossover with four paths: two drivers each for the bass, one each for the low and high mids and the high frequencies. A further so-called TIA tweeter driver sits directly in the sound port of the system which has no acoustic channels outside the housing as this would typically cause changes in the frequency and phase response.

Practical

The A6t model is designed as a straightforward in-ear playback system for professional use. Jack plug, cable and driver appear robust. Due to their custom made design, the earphones themselves sit permanently and securely in the ear canal.

A special feature of 64 Audio is the so-called apex damping modules (Air Pressure Exchange). Typically, in-ears act as a closed system and thus achieve a high degree of external insulation, but put more stress on the eardrum. The apex attenuation module is a small cylinder on the housing that relieves the pressure on the trapped air column in the ear and thus makes listening less tiring. The built-in module provides an external attenuation of 20 dB, which has practical value on stage. Compared to conventional products, the attenuation is deliberately less intense in order to reduce the pressure on the inner ear and thus meet the demands of prolonged use on stage. If required, an optional 15 dB module can be purchased to give the user even more “ambient sound”, which makes for easier exchanges with the audience and fellow musicians.

Sound

The following sound evaluation is based on a special version of the A6t, which was provided to us by the German distributor KS Distribution. These are designed as a kind of universal version, which are supplied with memory foam fitting pieces. The fitting accuracy of these test models is high, but conceptually less perfect than the actual purchased product. Therefore, one can assume that the “real” A6t give even greater advantages in terms of sound quality and wearing comfort.

The general sound impression is of a convincing the high-level and impedance-independent system (LID, Linear Impedance Design) with neutrality, high detail resolution, powerful and at the same time accentuated sound and impressive clarity without harshness.

On closer inspection, the A6t delivers a clearly perceptible but not overemphasised low bass that is cleanly defined throughout and reproduced in a clearly recognisable tonality. For example, the different TR-808 accents in Adel Tawil’s song “Katsching” are easily perceptible. Even higher basses are characterised by tight contours, richness of detail, dynamics and clean tonality. Modern pop and R&B productions, therefore, sound wonderfully punchy.

The wide range of the middles provides similar integrity. Acoustic instruments like grand pianos and even voices present their own authentic characters. You can hear important details such as the rasping in AC/DC’s Brian Johnson’s voice or the fine details picked up by a microphone, like breath, popping sounds and consonants. At the same time, the A6t also hits the spot in rock productions and ensures harmoniously distorted guitars or whipping snare drums come through. Finally, the treble range is generally open and refined. Percussion and detail resolution are given an elegant clarity that dispenses with bite. I would describe the harsh tonal limit as slightly forgiving. However, the A6t allows good judgement of the recording quality, letting you differentiate between flat and modern pumped up. The wide, precise and stable stereo panorama provides a good ambient impression. At the same time, even fast movements are always comprehensible (e.g. Yello: Pan Blue). Reverberation effects are also easy to follow (e.g. Tori Amos: Lust). The test headphones deliver a good result in terms of room depth and general three-dimensionality but, due to their design, they don’t come close to high-quality open headphones or even loudspeakers. Finally, they earn great praise for their dynamic reproduction. The quiet passages of a classical orchestral recording are, at least in quiet surroundings, translated to suit an audiophile.