Four Driver Hybrid In-Ear

64 Audio's U4s is a universal fitting counterpart to the custom fitting A4s released in 2021. This four driver Universal In-Ear Monitor (UIEM) features a Dynamic low-frequency driver, two balanced-armature drivers, and one patented tia driver; making it our fifth "hybrid" UIEM. U4s is designed with the ground-breaking patented technologies originally developed for our flagship products in order to bring a wider audience closer to their music.

Tia, LID, and apex are all housed in an ergonomic anodized aluminum shell along with an assortment of apex modules, ear tips, and an ultra-low impedance premium silver-plated copper cable.

U4s' Striking New Look

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.

Flagship Technology

The democratization of tia technology within our product range brings that classic 64 Audio sound signature to a new price-point. 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.

U4s Sound

Wide Nozzle Silicone Tips/m15 Modules (Standard Configuration)

The frequency response of U4s follows proven targets for fidelity and preference. It's powerful, enveloping, and deep while avoiding being muddy; this kind of bass can only be produced by a dynamic driver. U4s comes short of being classified as warm, rather it is like a tight and agile stand-mount speaker with a well implemented sub. The key to this is how the low-frequency rise starts low enough to keep out of the mid-bass.

Mids are revealing and present, contributing greatly to its wide stereo imaging and separation. U4s' perfect balance of presence and body lends itself well to every type of music and volume preference.

High frequency response toes the line between neutral and detailed. Mixes that are typically "bright sounding" translate nicely without being harsh or fatiguing.

U4s Apex Module Variations

m20 apex modules

Using the m20 apex modules with U4s increases sub-bass response while keeping the mid-bass clean. Works great for overly bright mixes, as it tilts the response slightly towards the low end. While this module slightly shrinks the sound-stage width, it works great for synth heavy or modern pop music that doesn't contain much acoustic spatial information. The m20 module also unlocks some of the missing sub information in older rock recordings. (increase by 1db- 2db at 40hz-20hz).

mX apex modules

Widest imaging with a reduction in noise isolation. Sub-bass response is greatly diminished, giving you the ability to attenuate to your preferences based on music type and mix. It is ideally used for recordings that do not capture much sub-bass content while containing a lot of spatial information. Because of the reduction in sub-bass response it creates a slight tilt towards the high-frequency band. (reduction by 1db-10db at 350hz-20hz).

The New m12 Apex Module

Releasing exclusively with U4s is our new m12 apex modules. They will eventually be made...