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.
Its ergonomic, anodized, aluminum shell houses a single dynamic driver, two BA drivers, and one patented tia driver, all weaved together with our patented Tia, LID, and Apex technology. The 4-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 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 is in keeping the low-frequency rise 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.
Tune Your Sound with Apex and Eartips
The included Apex Modules and Eartips each have different sonic characteristics. You can use different combinations to accentuate different aspects of U4s's 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 Module 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.)
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)
Outstanding performances from U4S and Bloom Audio’
As it says in the title, the U4S in just breathtaking! As is the customer support from the Bloom Audio team! I cannot believe how wonderful this staff is. They were insanely helpful from start to finish and offered so much insight into multiple IEMs before I landed on these.
The U4S themselves offer so much versatility and performance for the price! I purchased the M12 module to complement the 3 included and between the m12 and m15 they satisfy so many itches I had been missing with other sets.
Thank you Bloom Audio team, with a specific shoutout to Matthew and Caleb who put up with me from the start! You are just absolutely wonderful humans.
To;dr: Bloom Audio is wonderful, and but U4S! They are excellent!
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Brian H.
Outstanding IEMs
For IEMs in the $1k price range the 64 Audio U4s is the best I have tried. My ears are sensitive to larger, heavier IEMs but these are just right, with a snug non-fatiguing fit. The sound is just plain fun and musical, with just the right amount of treble and good solid bass. I don’t find the mids to be recessed at all in contrast to some reviews I’ve seen. They have wonderful detail retrieval and a really good expansive sound stage. I really like 64 Audio’s Apex Module system which allows me to adjust the tonal characteristics. It’s a great option that makes these IEMs a better value than the competition. These sound great with every genre I’ve thrown at them. I listen to primarily classical and these really shine with that, but jazz and rock sound wonderful as well. My only complaint would be in regard to the cable, which only comes in a 3.5mm termination. I much prefer these with my after market cables with a 4.4mm balanced connection. Otherwise I have nothing but praise for the U4s and can recommend it wholeheartedly to anyone looking for a top quality great sounding IEM.
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Andrew
The main thing I like about these IEMs is the comfort. The nozzle is not too long or wide, like other IEMs in this or higher price ranges. Very non fatiguing. Additionally, the sound is amazing for this price point as well!
The Apex modules are a fantastic idea and very user friendly for someone who does not know how to EQ.