64 Audio U18t

Professional in-ear monitor system with 18 balanced-armature drivers and pressure relief

In a nutshell

With the U18t, 64 Audio constructively explores the limits of what is possible with in-ear monitors. The sound results are completely convincing and meet the highest demands of stage musicians, sound engineers and audiophile music listeners without restrictions. The extra cost compared to the equally outstanding U12t is obvious, with the sonic gain being particularly noticeable in the areas of neutrality and spatiality. Without a doubt, the U18t and the custom-fit model A18t with list prices of 3,299 Euros require a budget that is by no means available to everyone. On the other hand, they demonstrate the upper limits of what is currently feasible in the in-ear monitor sector. The U18t are comparable with an expensive full-range studio monitor but, in this case, they can also be used as a mobile monitor.


64 Audio is one of the most important suppliers of professional in-ear systems. The Vancouver manufacturer supplies well-known artists such as Beyoncé, but also addresses the needs of sound engineers, producers and audiophile music listeners. With the U18t model, they have a record 18 balanced-armature drivers per channel.

64 Audio’s flagship product in the field of universal fit headphones actually offers more built-in systems than the competition. But more drivers on speakers does not necessarily mean an increase in sound quality. Rather, such a design requires a brilliant feat of design to achieve the kind of high sound level that you would expect when the price is over 3,000 Euro.

The foundation for this is laid by a stylish, red anodized, compact aluminium casing. It manages without additional internal audio conductors, which could have a disturbing effect on the frequency response and phase behaviour of the numerous drivers. A spectacular eight BA drivers operate in the bass range and the same number in the mid-range. There is also a further driver for the mid-high range and the TIA tweeter is placed directly in the sound port. Compared to the U12t model, the top of the 64 Audio range increases in both bass and midrange. The U18t also uses a passive crossover. These headphones are supplied with a plastic transport case, which also contains a cleaning tool and a clip for cable attachment.

In Practice

The ergonomically designed casing, built to meet the tough requirements of stage use, demonstrates high-quality workmanship and, thanks to the six memory foam adapters supplied, sits firmly and securely in the ear – a basic requirement for live applications. The twisted cable is routed over the auricle for stabilisation and is just as robust, and it is also interchangeable. The metal housing and gold-plated 3.5 mm angled jack mean there is no weak point in the connection. In practice, this means that the U18t is straightforwardly focused on professional music reproduction.


64 Audio’s in-ear monitors deliberately avoid a completely sealed system in which an enclosed column of air is moved between the driver and the eardrum. This type of construction can be quite demanding on the ears, especially at high levels and for long periods of use. The solution is so-called apex damping modules (Air Pressure Exchange). They can be embedded in the driver housing and come in two settings. These cylindrical elements provide pressure relief and turn the in-ears into half-open systems. Modules with an external attenuation of 20 dB or 15 dB are supplied. These place significantly less stress on the eardrum, which proves to be practical when used on stage.

Now you have some decisions to make. The U18t is a universal fit headphone, with wearing comfort that is consistently comfortable and secure. However, if you want an even better fit, you can also choose the sister model A18t. This is a bespoke variant that requires an ear impression, which is converted into a custom fit using 3D scanning and manufacturing methods. In addition, the colour and design of the ear impression can be almost freely defined by the customer. For performers, it is often desirable to make in-ears virtually invisible to the audience and this can be achieved by using transparent or skin-coloured materials. There is usually no extra charge for this apart from the fee required for a visit to a hearing specialist. In this way, the system is permanently adjusted to the needs of each individual.



With the models A6t and U12t , 64 Audio offers in-ear headphones which operate at a really high level of sound quality. With the U18t, the manufacturer is demonstrating the limits of what is technically feasible, addressing the requirements of even the most critical and demanding users.

This model pursues a completely neutral tuning which should, in addition, provide the highest quality in all aspects of reproduction. The design, which features 18 BA drivers per side, results in a sound image that leaves hardly anything to be desired and which, due to the size of the driver housings, is simply formidable. The basic tuning corresponds to the A6t and U12t models, but is somewhat more three-dimensional, more transparent and even more “honest”.

The U18t is a prime example of detail resolution, definition and transparency. Its levels also meet the requirements for use on stage. Minor details, dynamic movements, but also background noise, production and performance-related shortcomings can be detected without calling into question the coherence of the mix – assuming a good production. Weaknesses in flat mixes or inadequate recording technology are comprehensibly exposed. These characteristics make the U18t a valuable tool for production and for use on stage, as well as a joy for music lovers who adore details. The U18t reproduces source material across genres in its entire spectrum, timing and associated dynamics. Acoustic instruments and voices reach the ears vividly, sparingly mixed jazz recordings score points with wonderful dynamic realism, and large orchestras sound huge with many shades of sound colour and spatial influences. But the U18t also does justice to lush pop and electronic productions and provides the necessary power for rock. Gorgeous!

The bass range is extremely accurate. It reaches deep down to the sub-frequencies of current hip-hop and electronic productions, without getting out of step. Definition, dynamics and the comprehensibility of the played notes are outstanding in each case. The U18t are a little more linear than the U12t, which are a little more demanding in the low bass range.

This convincing performance is perfectly complemented by the equally lavishly equipped BA facility in the mids. The detail and authenticity in the reproduction of voices and instruments of all kinds is breathtaking. The U18t do not demonstrate any weaknesses in the uppermost part of the frequency spectrum either. They operate with high speed and exemplary transparency, ensuring not only brilliance but also precise detail separation of the sound components involved. This also applies to the structure of the wide stereo panorama and surround sound. Here, everything is firmly in place, but can be just as reliably traced during modulations. I didn’t detect any unwanted harshness; rather, they offer the professional user the facility for an accurate balancing act, so decisions can safely be made about the desired degree of bite. The same applies to the use of effects like reverberation and echo, equalizers or dynamic tools from sound production.

5 years ago by Ulf Kaiser
  • Rating: 4.88
  • Sound
  • Handling
  • Price/Quality
  • Function

Technical specifications

  • Ear couplingIn-ear
  • Typeclosed/semi-open
  • Transducer principleBalanced Armature (18 drivers)
  • Frequency response (headphones)10 - 20.000 Hz
  • Impedance10 ohms
  • Cable length120 cm

What's in the box

  • TrueFidelity foam earmoulds (S, M, L)
  • Silicone earmoulds (S, M, L)
  • m20 apex module
  • m15 apex module
  • Removable 1.2m premium cable
  • Cleaning Tools
  • Air dehumidifier
  • Shirt clip
  • Hardcase

Special features

  • Crossover: Integrated 4-way passive crossover
  • Isolation: -20 dB and -15 dB by supplied apex modules
  • Connection: 2 pin

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