64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm
64 Audio U4s - Quad Driver Hybrid IEm

64 Audio U4s - Quad Driver Hybrid IEm

CHF 1,199.00

Delivery time approx. 2 weeks

A quad-driver hybrid UIEM featuring groundbreaking patented technologies originally developed for our flagship products to bring their music to a larger audience.

With the U4s, 64 Audio has developed a bold new color aesthetic. The slate blue case color has been influenced by some of the finest blue dial watches, while the unique faceplate pattern is inspired by Muonionalusta meteorite fragments.

The luminescent properties of the front panel and the body give it a unique sound in different lighting conditions.


The U4s sounds light-footed, effortlessly delivering physically engaging sub-bass without spilling over into the mid-bass. Balanced mids and a comfortable high-mid band respond to a wide range of music and recording styles at any volume; they are present but not tiring.

The open, airy quality of the Tia tweeter combines with the extended soundstage of the Apex to deliver a lifelike audio experience.


Its ergonomic anodized aluminum chassis houses a single dynamic driver, two balanced armature drivers and a patented Tia driver, all woven with our patented Tia, LID and Apex technology.

The four-way crossover is enhanced by our patented electronic low-pass filter that reduces distortion in the lower frequency range. The selection of included Apex modules and ear tips invites you to further shape the sound depending on your preference and source material, while the extremely low-impedance, premium silver-plated copper cable ensures unhindered signal transmission.

The proliferation of tia technology across our range brings the classic 64 Audio sound signature to a new price point.



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: tia symmetrical armature open drivers, the tia single hole design and tia acoustic chambers. U4s features two main elements of the tia system: the tia driver and the tia single bore design.


Air Pressure Exchange (Apex) is a patented vent 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 venting reduces listener fatigue and provides a much more realistic sound image. Apex is available in four module variants for U4s: mX, m15, m20 and *m12.


Linear Impedance Design (LID) is a patented circuit that corrects the non-linear electrical resistance of the various driver sets that make up this 4-driver IEM. Different output impedances of source amplifiers in devices like smartphones, bodypacks, DAC/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.

Electrical low-pass filter

A crossover replaces traditional acoustic dampeners that can cause unwanted distortion from vibration and air turbulence. Instead of using acoustic dampeners to filter out unwanted frequencies after the driver creates them, the electric low-pass filter lowers distortion by eliminating unwanted frequencies before they reach the driver.

64 Audio U4s


  • 1 tia tweeter - 1 high-midrange - 1 midrange - 1 dynamic woofer
  • 10hz - 20kHz frequency response
  • 105dB/mW sensitivity @1kHz
  • Integrated 4-way passive crossover
  • 6Ω impedance @1kHz
  • Apex Technology Isolation: -20dB, -15dB, -10dB, -12dB

Black premium cable

  • 0.23 ohms total impedance
  • 7 x 7 x 4 multi-twisted
  • Silver plated OCC copper wire
  • 26AWG
  • Terminated with 3.5mm

Scope of delivery

  • U4s universal in-ear monitors
  • 64 Audio Premium Leather Case
  • TrueFidelity foam ear tips (S,M,L)
  • SpinFit silicone eartips (S,M,L)
  • Silicone ear tips (S,M,L)
  • 3.5mm black premium cable
  • Apex modules: m20, m15, *m12, mX
  • cable clip
  • Cleaning Tool
  • Round sticker