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Reviews
"Over the course of the last months I have played around with the U4s a lot. I have found myself reaching for it many times even when I had other higher end IEMs within my reach. The U4s' energetic sound can absolutely grab you and keep you attracted.
The U4s have become one of my daily drivers, especially when I'm at the office. It has also become my prime work-out and sports IEM. The bass of it keeps me on my toes and motivated to my fingertips."
64 Audio U4s Review - Headfonia
"Firm and detailed low end, perfectly balanced and natural mids, airy tia treble, and even a soundstage capable of wrapping to the back of a listener's head. The U4s offers itself as a reasonably priced endgame IEM, something that should be the case with any headphone or IEM that goes for just a little over $1000."
64 Audio U4s Review - Major HiFi
sound
The U4s sounds light-footed, effortlessly delivering physically appealing sub-bass without over-emphasizing the midrange. Balanced mids and a pleasant high-mid range respond to a wide range of music and recording styles at any volume; they're present but not fatiguing.
The open, airy quality of the Tia tweeter combined with the extended soundstage of the Apex creates a lifelike sound experience.
design
Technologies
tia
Tubeless In-Ear Audio (tia) is a patented IEM design methodology aimed at reducing unwanted resonances 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. U4s features two main elements of the tia system: the tia driver and the tia single-bore design.
apex
Air Pressure Exchange (Apex) is a patented venting system that vents air pressure within a sealed ear canal while maintaining standard IEM isolation levels, allowing musicians and music lovers to listen comfortably for longer. This venting reduces listener fatigue and provides a significantly more realistic soundstage. Apex is available in four module versions for U4s: mX, m15, m20, and *m12.
LID
Linear Impedance Design (LID) is a patented circuit that corrects the nonlinear electrical resistance of the various driver sets that comprise this 4-driver IEM. Varying output impedances of source amplifiers in devices such as smartphones, bodypacks, DAC/amplifiers, and DAPs typically result in a different frequency response, which depends on the slope of the resistance. Restoring the correct interaction with the source and maintaining the desired sound signature enables consistent, reliable sound.
Electrical low-pass filter
A crossover replaces traditional acoustic dampers, which can cause unwanted distortion due to vibrations and air turbulence. Instead of using acoustic dampers to filter out unwanted frequencies after the driver has generated them, the electrical low-pass filter reduces distortion by eliminating unwanted frequencies before they reach the driver.
Specifications
- 1 tia tweeter - 1 tweeter-midrange driver - 1 midrange driver - 1 dynamic woofer
- 10hz - 20kHz frequency response
- 105 dB/mW sensitivity @1kHz
- Integrated 4-way passive crossover
- 6Ω impedance @1kHz
- Apex technology isolation: -20dB, -15dB, -10dB, -12dB
Black premium cable
- 0.23 ohm total impedance
- 7 x 7 x 4 twisted multiple times
- Silver-plated OCC copper wire
- 26 AWG
- Finished with 3.5 mm
Scope of delivery
- U4s Universal In-Ear Monitors
- 64 Audio Premium Leather Case
- TrueFidelity foam earplugs (S,M,L)
- SpinFit silicone eartips (S,M,L)
- Silicone earplugs (S,M,L)
- 3.5 mm black premium cable
- Apex modules: m20, m15, *m12, mX
- cable clip
- Cleaning tool
- Round sticker
