Bellos Audio X4 - 4 Driver Custom In-Ear Monitor
Bellos Audio X4 - 4 Driver Custom In-Ear Monitor
Bellos Audio X4 - 4 Driver Custom In-Ear Monitor
Bellos Audio X4 - 4 Driver Custom In-Ear Monitor
Bellos Audio X4 - 4 Driver Custom In-Ear Monitor
Bellos Audio X4 - 4 Driver Custom In-Ear Monitor

Bellos Audio X4 - 4 Driver Custom In-Ear Monitor

CHF 999.00

Delivery time approx. 2 weeks.



Bellos Audio X4 CIEM

X-Series Matte Black Desktop

We are pleased to introduce the X4, our flagship X series of custom in-ear monitors. The X4 is the culmination of our commitment to providing an exceptional audio experience for musicians and audiophiles alike. With an additional ultra-high driver and our proprietary In-Air Canal technology, the X4 delivers unprecedented levels of clarity, detail and realism.

The X4's tuning is fine-tuned to deliver a warm sound signature that reveals every subtle detail of your music. The ultra-high driver ensures an extended frequency response and delivers a very smooth and natural sound. In-Air Canal technology enables the most comfortable CIEM listening experience. So comfortable that you feel like you have nothing in your ears! The X4 are the best in-ear monitors in their class and the perfect choice for anyone who demands the highest audio quality.

Like all models in the X series, they are equipped with a variety of additional technologies, such as: b. ATOM Venting that significantly expands the soundstage, beautiful 3D printed matte cabinets, the extremely durable RCX cable connector, modular drivers and removable front panels for quick and easy maintenance and repairs.

Estimated construction time: 5 days

(Construction begins as soon as we receive usable ear prints)

Bellos X-Series X4 Specs

Driver Specs

  • 1 Ultra high
  • 1 High
  • 1 Mid/Low
  • 1 Dynamic 6mm Low
  • 4-Way Crossover<


  • In-Air Canal Technology
  • 3D Printed Matte Finish Shell
  • ATOM Venting Technology
  • RCX Cable & Connector


  • 3 Balanced Armature drivers
  • 1 Dynamic Driver
  • Frequency Response: 20Hz – 20kHz
  • Impedance: 16Ω at 1kHz
  • Sensitivity: 116 dB/mW
  • Crossover: Integrated 4-Way Crossover
  • Isolation: -17dB (internal ATOM)


Our proprietary technologies that enable us to produce best-in-class custom in-ear monitors.

In-Air Channels

Bellos Audio Technologien
If you've ever used custom IEMs, you know that your ear canals deform when you open your jaw to sing or speak. As a result, the CIEMs lose their seal and feel uncomfortable in the ear. Introducing the revolutionary In-Air Canal technology. A patented design that allows for a complete seal at the opening (entrance) of the ear canal. It offers all the advantages of CIEMs without their disadvantages. They're so comfortable you'll forget you have them in!

ATOM ventilation

Bellos Audio Technologien
A pressure relief system that releases air pressure that builds up in a sealed ear canal. This increases the soundstage and greatly reduces listener fatigue, allowing you to hear more and listen longer. You no longer feel like you are cut off from your surroundings.

3D printed matte cases

Bellos Audio Technologien
Using our patented 3D printing technology, we design the custom in-ear monitors in 3D software with nanometer precision. The parts are printed and assembled efficiently by hand. Shortly thereafter, the matte finish is applied to the CIEM shell to ensure a very comfortable and organic fit with a "grippy" consistent seal.


RCX cable

Bellos Audio Technologien
One ​​of the most common sources of error is the cable. Our proprietary RCX cable changes this. The only cable connection designed specifically for custom in-ear monitors. It's for 5.000 connections designed without errors. The RCX cable comes with our standard CIEM 2 year warranty.

Removable faceplates

Bellos Audio Technologien
A revolution in the design of custom in-ear monitors. A traditional custom IEM must be cut open to be repaired. Our design features a faceplate that attaches with alloy steel screws, allowing us to repair custom in-ear monitors quickly and efficiently.

Modular drivers

Bellos Audio Technologien

The CIEM enclosure is designed to accommodate a pre-assembled driver package that is tested in advance to ensure it meets all specifications. Modular drivers can be installed and removed without damaging or destroying the CIEM housing.