64 Audio A4s - Custom In-Ear Monitor
64 Audio A4s - Custom In-Ear Monitor

64 Audio A4s - Custom In-Ear Monitor

CHF 1,199.00

Production time approx. 3-4 weeks

Custom In-Ears - High End In-Ear Monitors especially for you

64 Audio is proud to introduce its newest quad driver in-ear monitor, the A4s. This complete redesign of our four-driver platform is upgraded with the addition of the dynamic woofer driver, making it 64 Audio's second hybrid custom IEM.

Alongside this major update, the A4s features our Tia technology, LID and our patented Apex and 3Dfit technologies. The A4s' frequency response, detail, and soundstage outperform other audiophile products at almost every price point, although they're aimed at musicians looking for an immersive monitoring experience.


Exclusive technologies that challenge traditional in-ear monitor designs to bring you the absolute best listening experience

A4s features the following unique technologies:

64 Audio tia

Tubeless In-Ear Audio (tia) is a patented IEM design method that aims to reduce unwanted resonance and distortion for a transparent and lifelike sound signature. The tia system consists of three main elements: open tia drivers with a symmetrical armature, the tia single bore design and tia acoustic chambers. A3t features two main elements of the tia system: the tia driver and the tia single bore design.

Air Pressure Exchange (Apex) is a patented ventilation system that disperses air pressure in a sealed ear canal while maintaining standard IEM isolation levels, allowing musicians and music lovers to hear comfortably for longer. This ventilation reduces listener fatigue and provides a much more realistic sound image. Apex is available in three module variants for A2e: mX, m15 and m20.

Linear Impedance Design (LID) is a patented circuit that corrects the non-linear electrical resistance of the multiple driver sets that make up this 2-driver IEM. Different output impedances of source amplifiers in devices such as smartphones, bodypacks, DACs/amplifiers and DAPs usually result in different frequency response depending on the increase in resistance. Reestablishing the correct interaction with the source and maintaining the desired sonic signature allows for consistent, reliable sound.

3D-Fit preserves the details of your ear impressions using a new digital rendering and 3D printing process. The patented process of integrating acoustic tuning features into the housing of an IEM enables designs that would not be possible with traditional methods. We build these advanced and uniquely complex features into the shell to manipulate the sound produced by the IEM. This process also reduces distortion in the footprint, making for the most precise and comfortable in-ear monitors available.


  • 1 dynamic driver, 3 balanced armature drivers
  • 1 DD, 1 BA low-mid, 1 BA high-mid, 1 Tia high
  • Configuration of the hole: Simple
  • Frequency response 10Hz - 20kHz
  • Sensitivity 107dB/mW (94mV) @ 1kHz
  • Impedance 11Ω at 1kHz
  • Integrated passive 3-way crossover
  • Isolation: 20dB with m20 module, -15dB with m15 module.Comes standard with M20 module

Scope of delivery

  • A4s Custom In-Ear Monitors
  • 64 Audio Personalized Protective Case
  • Dehumidifier
  • Cleaning Tool
  • Shirt clip
  • 48" or 64" detachable professional cable
  • m20 Apex Modules
  • Round sticker
  • Product manual

Custom Options

You can customize any 64 Audio Custom IEM with the following options Here's how:

Custom In-Ears - High End In-Ear Monitors especially for you

64 Audio Custom In-Ear Options

64 Audio Custom In-Ear Options

64 Audio Custom In-Ear Options