64 Audio U4s | Hybrid Dynamic + BA Universal IEMs

64 Audio U4s Delivers Flagship Tech at an Affordable Price 4-driver hybrid IEM delivers classic 64 Audio performance with a new twist The slate blue shell provides a bold, stylish look The Tia treble driver delivers crisp, clear highs with the new dynamic driver providing deep sub-bass Includes Apex modules for varying isolation, silver-plated copper cable, carrying case, and plenty of ear tips Check out our measurement of U4s Bloom's Take The U4s continues in 64A’s tendency of taking a popular custom IEM style & tuning and converting it into a universal fit that audiophiles crave. They renovated the 4-driver hybrid design of the A4s into a universal shell and slapped on their lowest price yet for a UIEM. Overall, the design is like the popular U6t, Nio, and Fourte, features an anodized aluminum shell with dark gray pearl faceplate, and includes standard 64A package and accessories. Tuning lands in the popular Harman-esque “bass boosted neutral” but is differentiated in the quality of the bass and excellent air and resolution in the upper treble. It also displays strong imaging characteristics with a reasonably wide and three-dimensional soundstage, albeit not expansive. U4s offers a taste of the 64 Audio signature sound, quality, and engineering at a much more affordable price and is poised to become the new king of the $1099 IEM range. Read our full review here. Not sure which 64 Audio IEM is the right fit for you? Check out our 2024 Buyer's Guide for 64 Audio here! Bold New Look and Sound 64 Audio's fiercely popular U4s features an ergonomic Aluminum shell, a Dynamic driver, x2 BAs, and a patented Tia driver, enhanced by custom 64A Tia, LID, and Apex technology for precision and clarity. A 4-way crossover with a proprietary low-pass filter minimizes distortion, while apex modules and ear tips allow for sound customization. Powerful, deep bass remains tight and controlled in the U4s, avoiding muddiness. Revealing mids enhance stereo imaging and separation, creating a balanced, immersive sound suited for any genre and volume preference. Tune Your Sound The included Apex Modules and Eartips each have different sonic characteristics. You can use different combinations to accentuate different aspects of U4s' sound. mX Module Widest imaging with a reduction in noise isolation. Sub-bass response is 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. m12 Gold Module (*Not included with U4s) Developed for those who feel the bass drop between m15 and mX is too drastic. Perfect for tracks where the bass is slightly overpowering the rest of the spectrum. Increases mid-range punch (reduction by 1db-4db at 130hz-20hz.) m15 Module The m15 module strikes the perfect balance between bass attenuation and isolation, featuring dual ambient ports that are larger than the single port in the m20. With -15dB isolation and an additional -4dB reduction at 20Hz compared to the m20, it offers a more open, natural listening experience while still maintaining effective noise control. m20 Module Greatly increases sub-bass response while keeping the mid-bass clean. Works great for overly bright mixes as it tilts the response towards low end. While this module 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.) Foam Tips Narrows the mix and shifts HF resonant peak down. More secure fit. Spinfit Shifts HF resonant peak up. Best at handling microphonics and occlusion effects. The nozzle is decoupled well from the silicone touching the ear canal. Wide Nozzle Staging is less localized with better panning blend. Hits target frequency response curve with m15 module. Specifications Transducer Configuration (x1) Dynamic driver (Lows) (x2) Balanced Armature drivers (Low Mids, High Mids) (x1) Tia driver (Highs) Frequency Response: 10Hz – 20kHz Sensitivity: 107 dB/mW @ 1kHz @ 1mW (94mV) Impedance: 11Ω @1kHz Crossover: Integrated 4-way passive crossover Isolation m20 Module: -20dB m15 Module: -15dB m12 Module: -12dB (*not included with U4s) mX Module: -10dB Cable 0.23Ω total impedance 7 x 7 x 4 Multi-twist Silver-plated OCC copper wire 26 AWG 3.5mm termination 64 Audio 1 Year Warranty In the Box 64 Audio U4s IEMs Leather carrying case TrueFidelity ear tips (S/M/L) Silicone ear tips (S/M/L) SpinFit ear tips Ear tip holder Black premium Silver-plated copper cable with 3.5mm 64 Audio Apex modules (mX, m15, m20) 64 Audio Sticker