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: 1 Year 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!
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: 1 Year 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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TRUSTED BY OVER 35K+ MUSIC ENTHUSIAST
Let customers speak for us
from 4839 reviews
I recently got my hands on the ROSESELSA AURORA Ultra IEM, and I must say, it has exceeded my expectations! For under 2,000 INR, this IEM delivers exceptional value and performance that can easily compete with many pricier models out there.
What really stands out to me is its versatility. The AURORA shines across all genres, whether I'm diving into classical symphonies, jamming to rock anthems, or vibing with electronic beats. The sound quality is simply fantastic, making every listening session a joy.
A cherry on top is the comfort factor—these IEMs are small and lightweight, so they don’t cause any discomfort during long listening sessions. If you’ve had issues with larger IEM shells in the past, you’ll find the AURORA to be a perfect fit. Plus, the cable quality is impressive for the price, adding to the overall value of this product.
To unlock the full potential of these IEMs, I highly recommend investing in an external dongle. I personally use the Kiwi Ear Allegro Mini DAC, and it has truly elevated my audio experience. If you're on the hunt for a budget-friendly IEM that doesn’t compromise on sound quality, the ROSESELSA AURORA is a must-try!
I also want to take a moment to thank the audio store for their outstanding service. My order arrived in perfect condition, and their customer support team was incredibly friendly and helpful. Overall, this has been a wonderful experience, and I’m absolutely thrilled with my purchase!
As a v16 owner this is a worthy upgrade .
Fit :
The iem is designed aesthetically that it fits like custom made
Sound impressions :
Treble is perfectly done with being sibilant, Mids sounds very organic and clear, Bass is the best part here it's a step up from their previous flagship v16.
Staging is better and so is the resolution, A total flagship level iem which punches above the price tag
Thanks to Pritam for his exceptional customer service and deal .
Definitely recommended

Have a great features and I am very happy after buying this m71 thanks audio store 🙏🙏

Time Spent with this DAP is more than 50 days, used many IEMs from Budget range to high end.
OBSERVATION & EXPERIENCE SO FAR.
- Wide soundstage, it's creating a spacious listening experience.
- Smooth and refined sound, with good bass & trebles. I liked it.
- little high Volume doesn't hurt ears because of spaciousness which this DAP creates.
- Main unique point is Vocals & Instruments separation, it's best.
- So far, I noticed Battery back up is really good. Will check it over time and provide feedback.
- Does not get warm that too after using for hours.
- Best software & Shanling Music app, it's very fast ( I use 1TB fully loaded Micro SD card.)
Please Note - Little more care is needed while handling as it has Glass tubes. Again it's unique offering & tubes makes music more enjoyable.
CONS-
1. Charging time ( it will get solve by software updates in future, Brand has co
nfirmed it in their post)
2. Only one colour option is available from Brand.
3. Some settings currently not present, Brand may add in future updates ( DSD gain Compensation, PEQ, MSEB, Night light short cut in quick pannel)
CONCLUSION-
a. Highly recommend those who want detailed & immersive experience.
b. THREE IN ONE- One DAP but three modes, all three sounds differently. One mode Transistor (without Tubes) and two Tube modes (Triode & Ultra- linear).

Sterdy & beautiful cable. I am using it with Hidiz MP145 Planner Magnetic IEM. It add details to music over stock cable. Makes all aspect of sound quality better.

I am writing review after One month regularly uses with my two DAP - Shanling M8t, Hiby R4.
POSITIVES-
1. Best Soundstage
2. Balanced sound
3. Musical & Makes music more enjoyable to ears.
4. No fatigue despite of metal construct.
5. Weight distribution is really good.
6. Largest Magnetic planner in the Category.
7. Details & instruments separation at best.
CONS-
1. Small ears may face challenge. Plz contact team ATS before purchase. Normal ear size, No issues with fit & long usage.
2. Stock cable is good but doesn't suit this IEM.
I am using this with Divinus Auram cable, which goes really well with this by appearance as well as by performance.
CONCLUSION-
1. Very very happy with the purchase. It's my main IEM in daily music journey.
2. My suggestion is Music enthusiast must have atleast one 'Planner Magnetic IEM', believe me I found that the the songs which I am listening since decades are sounding differently with some more details with this IEM.

The KZ Castor is an excellent choice for budget audiophiles. It delivers superb sound quality that rivals much more expensive headphones, with clear highs, rich mids, and deep bass. The build quality is solid, offering both durability and comfort for long listening sessions. At its price, it’s a fantastic value, outperforming many premium options. Highly recommended!

i think it's a great choice for someone who's just starting with the "iem" audiophile thing and it sounds good pretty good for the price range, it's sound clear and crisp, the bass is a little on the lower side but nonetheless great product if you are just starting, oh and yes the delivery was fast got it in a day.

Delivery was fast and item received was in good condition

Lets get to the point, its the best budget IEM!
I have been in the IEM space for more than 6 months and I was looking for a daily driver that can handle rough use, and then Pritam Sir suggested me 7Hz G1. And it failed to disappoint me!
A nice high quality well built iem, with one of the best ergonomic design, and a proper sound isolation with tons of tip to choose from.
The iem is well tuned with proper instrument seperation and clarity, warm tuning with perfect bass and excellent soundstage compared to other budget IEMs.
If you are new to yo IEM and want to buy your first IEM, blindly go with this! Trust me you would not regret! For 3.2k, its a steal deal!
(Pro Tip: Always listen to Pritam Sir's suggestions. He is the G.O.A.T)

We had an amazing experience at The Audio Store. Pritam, the shop expert, was incredibly helpful and knowledgeable. He patiently guided us through the world of in-ear monitors, explaining all the details and helping us understand what would work best for our band, Rhythm Freak. He suggested options that perfectly matched both our budget and our musical needs, making sure we got the best value without compromising on quality. Thanks to his expertise, we walked out confident and satisfied with our purchase. Highly recommend this store to any musician looking for top-notch gear and excellent service

Sound quality ausom but not for base lover's

Top notch earphone Mike quality 🔥.gaming, music etc highly recommend ❤️🎧

I believe this is the best tws under 10000 rupees also it is an iem

Thank you audio store. The sound is amazing. It was delivered within time and product was perfect.