64 Audio U4s Hybrid Universal-fit In-ear Monitors

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A quad driver hybrid UIEM featuring ground-breaking patented technologies originally developed for our flagship products in order to bring a wider audience closer to their music. U4s explores a bold new color aesthetic for 64 Audio. The Slate Blue shell color was influenced by some of the world’s most beautiful blue- dial timepieces while the unique faceplate pattern is inspired by Muonionalusta meteorite fragments. Both the faceplate and shell’s illuminant properties give it a unique tone in varying lighting conditions.


U4s sounds light on its feet while effortlessly delivering physically engaging sub-bass without bleeding into the mid-bass. Balanced mid frequencies and a pleasant high-mid band respond well to a wide array of music and recording styles at every volume level; present but not fatiguing. The tia high-driver’s open airy quality couples with the extended sound-stage provided by apex for a lifelike sonic experience.

Its ergonomic anodized aluminum shell houses a single dynamic driver, two balanced-armature drivers, and one patented tia driver; all weaved together with our patented Tia, LID and Apex technology. The four-way crossover is elevated with the use of our proprietary electronic low-pass filter; reducing low- frequency distortion. The assortment of included apex modules and ear tips are an invitation to further shape the sound based on preference and source material while the ultra- low impedance premium silver-plated copper cable ensures unimpeded signal transmission. The dissemination of tia technology within our product range brings that classic 64 Audio sound signature to a new price-point.


1 tia High Driver – 1 High-Mid Driver – 1 Mid Driver – 1 Dynamic Low Driver
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 Ohms Total Impedance
7 x 7 x 4 Multi-Twist
Silver Plated OCC Copper Wire
26 AWG
Terminated in 3.5mm


U4s Universal In-Ear Monitors
64 Audio Premium Leather CaseTrue
Fidelity Foam Ear Tips (S,M,L)SpinFit Silicone Ear Tips (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