Fosi Audio IM4 Open-Back IEM – Audiophile Clarity, Tuned Your Way
The Fosi Audio IM4 Open-Back IEM is engineered for listeners who crave natural tonality, wide soundstage, and long-session comfort. Built around a 10mm PU beryllium-coated dynamic driver, the IM4 uses an N52 dual-magnet, dual-chamber architecture to deliver fast transients, controlled bass, and articulate mids with airy, detailed highs.
Its open-back acoustic design, combined with internal damping wool, minimizes resonance and listening fatigue—resulting in a relaxed, spacious presentation that feels closer to high-end open headphones than conventional in-ear monitors. Whether you’re a critical audiophile, a music enthusiast, or a creator seeking realism, the IM4 offers a refined yet engaging Hi-Fi sound.
Precision-machined from 6063 CNC aluminum alloy, the IM4 showcases premium craftsmanship with a minimalist aesthetic. The lightweight, ergonomic shells (just 7g per earpiece) ensure all-day comfort, while the striking orange metal grille adds a distinctive visual identity.
Sound personalization is at the core of the IM4. With interchangeable brass and aluminum nozzles and three types of eartips (Balanced, Bass, Deep Bass), you can fine-tune the sound signature to match your music and preferences. A detachable 2-pin 0.78mm cable with high-purity silver-plated OFC conductors ensures reliable connectivity and future upgrade flexibility.
Warranty Period: 1 Year from the date of Invoice
Covered: Manufacturing Defects Only
Warranty Form: https://www.theaudiostore.in/pages/warranty-claim-form
Cable: 1-month warranty only for manufacturing defects only
Fosi Audio is a dynamic brand dedicated to providing the most comprehensive range of Hi-Fi audio products in the market. We cater to passionate audiophiles by offering Hi-Fi products, DIY kits, and expert guidance, ensuring an immersive audio experience. Beyond a mere transaction, we foster enduring relationships with our clients, supporting them throughout their audio journey.
Our diverse product lineup includes the Hi-Fi power amplifier, pre-amplifier, headphone amplifier, DAC, music player, Bluetooth receiver, DIY board, DIY chassis, and an array of DIY kits. These meticulously crafted offerings embody our commitment to exceptional sound quality and innovation.
Established in China in 2017, Fosi Audio was founded by a team of devoted audiophiles. Our products have gained significant popularity within the Chinese DIY audio community, amassing a large and dedicated following. To expand our reach beyond borders, we launched this website in 2017 and began offering a selection of products on Amazon under the name "Fosi audio." However, please note that many of our outstanding products are not yet available on this website or Amazon. If you cannot find what you're looking for, simply reach out to us via email, and we will be delighted to assist you in finding the perfect product to meet your needs.
At Fosi Audio, we are not just a brand; we are your partner in achieving audio excellence. Join us on this immersive sonic journey and experience the true essence of Hi-Fi audio.
These are my fourth pair of IEMs, and honestly, I can’t find a single fault with them. The sound signature is beautifully smooth, well‑tuned, and perfectly balanced. Vocals come through with striking clarity, making every track feel alive. Totally worth it — they deliver an experience that goes beyond expectations.
KEFINE Klean SV IEM
03/14/2026
Pratik Baral
Budget King!
I’m really impressed with the Hiby R1 — such a compact device, yet it delivers powerhouse performance. The raw specs on a spreadsheet don’t capture the real experience. Once you pair it with Type‑C IEMs and play FLAC files, the sound quality speaks for itself: clean, detailed, and surprisingly dynamic for something so portable. It’s proof that great audio isn’t just about numbers, but about how the gear actually performs in your hands (and ears).
HiBy R1 Hi-Res Portable Music Player
03/14/2026
Durga Anusha
Great Experience
It was neatly packed and unexpected case has been delivered along with the DAC. Had a nice experience too with the product. Loved it!
AUDIOCULAR SPARK Hi-Res Portable DAC Dongle CX31993 + MAX Amp
03/13/2026
Aniket Mondal
What sweet sound!!
I've previously owned some budget iems like kz zex, tangzu wan'er and chu 2 but Ohh boy the sounds on STA HI-END is so soothing and melodious and it handles eq like a champ so no complaints from there too. Absolutely go for it you won't regret
EarAcoustic STA-Hi End Series IEM
03/13/2026
Shubham
Powerful
Powerful, clear and you can hear the complete trace of audio.
AUDIOCULAR SPARK Hi-Res Portable DAC Dongle CX31993 + MAX Amp
03/13/2026
sarthak sahu
Excellent Value with Balanced Tuning
I have been using the Tanchjim Bunny DSP for a while, and for the price, it’s honestly a very good set of earphones. The build quality is very simple but good, and the light weight makes it very comfortable for long usage.
The sound quality is very balanced for the price. The bass is good and controlled rather than overemphasized, and the mids are good so that the vocals are very natural, and the trebles are good and detailed but not harsh. This makes them very good for all types of music.
The Tanchjim Bunny DSP is a very good earphone for the price, and I would recommend it for people who are looking for a very simple plug-and-play earphone with good sound quality.
TANCHJIM Bunny Type-C DSP Plug with Mic IEM
03/12/2026
Mayuresh Purkait
Very Good Sound
Sound is very good and accurate.. Soundstage is also wide and deep.. Like this Bunny...
TANCHJIM Bunny Type-C DSP Plug with Mic IEM
03/10/2026
R.A.
Good
Overall good quality
AUDIOCULAR SuperMix 6 Hybrid Premium Eartips for IEMs
03/07/2026
Anonymous
WelI i loved the iem Its good for my studyinh
WelI i loved the iem Its good for my studyinh and music session go for it iems
SIMGOT EW300 IEM
03/07/2026
bhavin patel
3 Months
Bets budget dac that gives you clear mids and more treble extension... If you are into edm trance symphony orchestra style music... then you will hear better instrument separation...
The cable is soft material so not for on the go will wear and tear... If you are musichead and always hooked then better go with audiocular beam it has cavlar braided cable for good rough n tough life space
AUDIOCULAR SPARK Hi-Res Portable DAC Dongle CX31993 + MAX Amp
03/07/2026
Alkesh Naik
Heard a lot of stuff on internet about this dac like hitching or buzzing sound and was bit nervous
Heard a lot of stuff on internet about this dac like hitching or buzzing sound and was bit nervous , but after purchasing I haven't faced any problem with it and I'm fully satisfied with the build and sound quality of the product.
AUDIOCULAR SPARK Hi-Res Portable DAC Dongle CX31993 + MAX Amp
03/06/2026
S.D.
Very satisfied
This is one of the best case I have used till today. Definitely beats other cases at this price range. It is much better than the generic cases available on Amazon, Flipkart, etc.
I have recommended this case to my friends who were so impressed on seeing it.
EarAudio In-Ear Monitors (IEM), Earphones Carry Case
03/05/2026
HET ANGHAN
You should definitely buy this
Why?
The quality of music that it is deliveing is Awesome . I was not sure if it is worth investing before buying. But after I tested it , it was phenomenal .
Also I would like to thank The Audio Store , they packaged this box so nicely , it has 4 to 5 level of protection, Also I was not expecting the case , it is cherry on the cake, I was bored of that low quality cases.
Thank You The Audio Store
You're the best
AUDIOCULAR SPARK Hi-Res Portable DAC Dongle CX31993 + MAX Amp
03/03/2026
Dibyam Oraon
Good
Good
Audiocular ARC Hi-Res Type-C IEM With Mic
03/02/2026
Swamyvaitla
To day it was delivered today me two days in
To day it was delivered to me two days in advance to expected delivery. I fixed it to my 4.4mm balanced male of my FiiO FT 7 headphones It's performance is extraordinary. Thank you Ear Audio store for supplying good quality adopter. It's built quality is also very beautiful.
EarAudio 3.5mm Male to 4.4mm female Adapter Cable
03/02/2026
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