Description
Enjoy a ground-breaking performance with the 64Audio U4s. This hybrid quad-driver IEM features the same patented audio technologies like tia and Apex Core developed for flagships at an irresistible price point.
Created For You
Experience a light and engaging sound with impressive sub-bass without compromising mid-bass clarity with the 64Audio U4s. Its balanced mid frequencies and pleasant high-mid band perform well with various music genres and recording styles, without causing listener fatigue. The tia high-drive r's airy quality and the extended sound-stage from the Apex Core technology provide a lifelike and immersive listening experience.
Tuned For You
The 64Audio U4s achieves a powerful, deep, and enveloping sound without sacrificing clarity, thanks to its dynamic driver. Its frequency response follows proven targets for fidelity and preference, avoiding muddiness and excessive mid-bass. The mids are revealing and contribute to its wide stereo imaging, while the high frequencies strike a balance between neutrality and detail, offering the perfect blend of presence and body.
Beautiful Blue
The 64Audio U4s features a Slate Blue shell with a unique faceplate inspired by Muonionalusta meteorite fragments. The colour was influenced by beautiful blue-dial timepieces and the illuminant properties of the shell and faceplate give it a distinct look in different lighting conditions.
Listen with the Best
The U4s boasts an ergonomic anodised aluminium shell that contains a single dynamic driver, two balanced-armature drivers and one patented tia driver. Its four-way crossover is further enhanced by the proprietary electronic low-pass filter, reducing low-frequency distortion. The ultra-low impedance premium silver-plated copper cable guarantees uninterrupted signal transmission.
Put a Lid on It
The different source amplifier output impedances of smartphones, DAC/Amps, Hi-Res Audio Players and more, can cause the frequency response to varying across devices based on the increase in resistance. A patented Linear Impedance Design (LID) circuit corrects the non-linear electrical resistance of the multiple drivers sets to restore proper interaction with the source device. It preserves the desired sound signature while staying constant and reliable.
Enjoy Your Music with tia
The U4s’ patented Tubeless In-Ear Audio (tia) system reduces unwanted resonance and distortion for a transparent and lifelike sound. This is achieved by allowing the Dynamic Driver and tia Balanced Armature Drivers to radiate freely in the single large tia bore with no obstructions in front of the drivers. It features special acoustic chambers instead of tubes that constrict the sound of the drivers.
No Dampers, It’s Electrifying!
Old technologies like acoustic dampers merely blocked frequencies from reaching the ear instead of preventing it from reaching the drivers. This introduced distortion due to the vibration and air movement at higher volumes. The 64Audio U4s uses the same electrical low pass filter, developed for the outstanding U18s, which reduces distortion while eliminating unwanted target frequencies before they reach the driver.
Apex Core Technology Looks as Good as it Sounds
The Air Pressure Exchange (Apex) Core allows a seamless airflow to the solid anodised aluminium shell that uses a perforated grill on the elegant faceplate to prevent the obstruction of air for effortless reproduction of music and minimal physical fatigue. This patented vent releases air pressure for better comfort and lesser fatigue while enhancing noise isolation. This technology comes in four module variations: mX, m12, m15 and m20.
Know Your Modules
- mX: Provides wide imaging with reduced noise isolation and a decreased sub-bass response. Perfect with recordings that have more spatial information and less sub-bass content. The reduction (by 1db-10db at 350Hz-20Hz) in the sub-bass response creates a slight emphasis on the high-frequency band.
- m12: Developed to address concerns from users who found the bass drop between m15 and mX to be too significant by reducing bass by 1dB-4dB at 130Hz-20Hz. Ideal for tracks where the bass is slightly overpowering other frequencies and can provide increased mid-range punch.
- m15: Enhances the audio staging by creating a natural and less localised sound. It also provides a better panning blend, resulting in a more cohesive and immersive listening experience and an accurate target frequency response curve.
- m20: Increases sub-bass response while keeping the mid-bass clean, making it ideal for bright mixes and modern pop music. While the sound-stage width is reduced, it works well for synth-heavy tracks and unlocks missing sub-information in older rock recordings.
TRANSDUCER TYPE/COUNT
2 balanced armature drivers, 1 tia driver, and 1 dynamic driver
TRANSDUCER CONFIGURATION 1 dynamic low, 1 BA low-mid, 1 BA high-mid, 1 tia high
FREQUENCY RESPONSE 10Hz – 20kHz
SENSITIVITY
107 dB/mW @ 1kHz @ 1mW (94mV)
IMPEDANCE 11Ω @1kHz
CROSSOVER
Integrated 4-way passive crossover
ISOLATION
-20dB w/ m20 module
-15dB w/ m15 module
-12dB w/ m12 module
-10dB w/ mX module
CABLE
0.23 Ohms total impedance
7 x 7 x 4 Multi-twist
Silver-plated OCC copper wire 26 AW
In The Box
•U4s Universal In-Ear Monitors
• 64 Audio Premium Leather Case
• TrueFidelity Foam Eartips (S,M,L)
• SpinFit Silicone Eartips (S,M,L)
• Silicone Eartips (S,M,L)
• 3.5mm Black Premium Cable
• Cable Clip
• Cleaning Tool
• Apex Modules: m20, m15, *m12, mX
• Round Sticker
Warranty Period: 2 Years from the date of Invoice
Covered: Manufacturing Defects Only
Warranty Form: https://www.theaudiostore.in/pages/warranty-claim-form
64 Audio is a leading manufacturer of high-end in-ear monitors for audiophiles, musicians, and professionals. With a focus on innovation and craftsmanship, 64 Audio delivers unparalleled sound quality and precision. Discover their range of custom and universal-fit models at The Audio Store and experience audio like never before. Shop now!
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Let customers speak for us
from 6248 reviews
This is my first IEM, and coming from Sony MDR 7506 and Airpods Pro i feel this sounds more richer and detailed.

It was great purchase and I'm happy from the output of this one. And as much as i love music , i have specific demands to meet like well balanced mids and highs but also good punchy bass. I'm happy with this purchase and i love it.

This was my first purchase from The Audio Store, and I was a bit hesitant at first, but they proved me wrong! The whole process was seamless, and I even received my order earlier than expected. The IEMs are really good and totally worth the money.
If this is your pick than go for it blindly!!!👌🎧

These are a great pick if you love a balanced sound. The best thing about them is the vocals — clear, natural, and full of emotion. You can really feel the singer’s presence without any sharpness or muddiness. Everything just sounds right, especially for long listening sessions.

Audiocular packaging is premium always give a small pouch which can be very handy.Initially Right side was not working in my KZ Harman target Balanced version. Date Recd 7th Oct 2025! every thing is awesome Love Pritam for being Down to earth.I am going crazy at age 51 with this music world man

Some online product selling giants didn't understand how to package product because it delegate and wants to handle with care and I really appreciate your customer support thank you great product delivery app in reasonable rate

It’s a neat dongle with crisp sounding music, it’s on a brighter side of music

one of the best earbuds in this price range.

As a beginner audiophile I did research on all budget IEMs but this KZ EDC Pro stood out in all reviews as best and most affordable no-nonsense IEM without distortion in sound output that drew my attention to it. And I am glad I made the choice, this deserves every bit of praise for the price & sound output better than my 5000INR TWS from reputed brands, a little bit EQ Tweaks just enhances the experience multifold... Must but for those who looking for affordable yet best sounding wired earphones/IEM. Brilliant build and sound quality for the price. A Must buy on a tight budget, and Thanks to audiostore for delivering package before scheduled delivery time.

Great DAC for the price in terms of build and aesthetic. When paired with a good IEM definitely makes the experience worth investing. Just go for it, must buy for a beginner/intermediate audiophile...!

Easy blind buy for the price. Most recommended set of iems if you're new to the iem community and are looking for something under 5000 rupees. Sounds clean and has a lot of customisation options with app support.

good sound and clear even without the dac and anything haven't tuned anything still clear sound!

After having owned a few kilo-buck IEMs, I was prepared to get something that was insane and probably endgame and rightly so Pritam sir recommended the FIR audio Xenon 6 and thus deep dived into this and I am sure this would be the end game IEM for me.
The XE6 is so wonderfully crafted looks like piece of jewelry and although a large IEM it is very comfortable for me for long sessions.
It sounded good from the start and was really different from the other IEMs. It started to sound even better and grew on to be the best I ever heard after listening to it for longer. I paired with Astell&Kern SP3000T and Hiby rs8 II and with desktop DAC Amps (FiiO K19, Topping D70. A70, Hifiman R2R and Xduoo TA 22) and the immersive, warm, musical and soundstage that filled my head all over. The sub bass is where it stands out the most, but the mids and highs are also so clear and crisp. I havent yet tried to change the atom modules as yet, I am sure this will make the XE6 even more great than that it already is.
The shells in the IEM I were crafted in the US (was crafted in China earlier, but as Trump wanted his MAGA force it had to be made in the US now)
This is definitely end game worthy!!!!

I’ve been using the Moondrop Chu 2 for around 5 months, and I’m really happy with them overall. The size is very good – small, lightweight, and comfortable for long sessions. They fit well in the ears and don’t feel bulky at all.
In terms of sound, they’re excellent for the price. Clear mids, detailed highs, and a balanced tuning that works great for vocals and instruments. They still feel solid and well-built even after months of daily use.
The only drawback is the bass – while it’s clean and controlled, it’s not very strong. If you’re looking for heavy bass, these might not fully satisfy you.
But if you want clarity, balance, and detail in a compact design, the Chu 2 are a fantastic choice.

Very good value for its price range,
Solid build, durable metal shells
Comfortable fit and decent ergonomics
Tuning flexibility thanks to interchangeable nozzles
Soundstage depth isn’t exceptional (though width / height are decent)
The black nozzle for brighter tuning is a bit aggressive.