Fosi Audio IM4

Open-Back In-Ear Monitor

Suscribe to Get 35% off on Kickstarter 

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Retail Price: $99.99

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Fosi Audio IM4

Open-Back In-Ear Monitor

Suscribe to Get 35% off on Kickstarter 

Thanks for contacting us. We'll get back to you as soon as possible.

Retail Price: $99.99

Fosi Audio P4 Preamplifier

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10mm PU Beryllium-coated Diaphragm 

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PU ensures smooth mids and punchy lows, while the beryllium coating adds clarity and sparkle to high frequencies. 

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N52 Dual-Magnet  

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A powerful, stable magnetic field improves control and speed, delivering cleaner sound with better dynamics.  

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Dual-Chamber Acoustic Design 

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The front chamber’s nine-port design ensures balanced frequencies, while the rear chamber extends treble detail.   

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Dual-Axis Ear Cup Arms

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Allows seamless vertical and horizontal rotation for a custom fit to different head shapes, enhancing both comfort and stability. 

Stepless Silicone Adjustment 

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OFC Silver-Plated Cable 

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Braided with 4 strands of 392-core 5N high-purity OFC silver-plated wire, the cable offers excellent signal transmission and shielding for richly detailed sound. 

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1.Open-Back Design 

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Minimizes internal reflections and pressure buildup, creating a more open, natural sound with reduced fatigue. 

2.Acoustic Damping 

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he rear chamber is filled with acoustic damping material to absorb standing waves, reducing distortion and harshness. 

3.Meticulous Tuning  

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Tuned with listener feedback to ensure smooth, balanced sound across genres—ideal for relaxed, extended sessions.

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The headband features a silicone adjustment slider with a damped, smooth feel, enabling easy and precise positioning based on personal preference. 

Durable Memory Metal Headband 

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Made of high-strength memory metal, the headband maintains its shape over time. Lightweight and flexible, it reduces pressure and enhances comfort. 

Breathable, Skin-Friendly Earpads 

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Crafted with perforated leather and breathable fabric, the earpads stay cool and soft. Memory foam inside ensures all-day comfort without overheating. 

10mm PU Beryllium-coated Diaphragm 

PU ensures smooth mids and punchy lows, while the beryllium coating adds clarity and sparkle to high frequencies. 

N52 Dual-Magnet 

A powerful, stable magnetic field improves control and speed, delivering cleaner sound with better dynamics. 

OFC Silver-Plated Cable

Braided with 4 strands of 392-core 5N high-purity OFC silver-plated wire, the cable offers excellent signal transmission and shielding for richly detailed sound. 

Dual-Chamber Acoustic Design 

The front chamber’s nine-port design ensures balanced frequencies, while the rear chamber extends treble detail.  

Refined Metal Finish Skin-Friendly Comfort 

Crafted from CNC-machined aluminum alloy with a sandblasted and anodized finish, it offers a smooth touch that’s gentle on the skin. 

Lightweight Design Only 7g per Earbud 

The hollowed structure cuts weight to just 38g with the cable, ensuring pressure-free comfort for long listening. 

Ergonomic Shell Contoured for Ear  

Developed with insights from millions of hearing-aid fitting samples, the ergonomic housing adapts to diverse ear shapes, delivering a secure and seamless fit. 

Sound Nozzles 

Comes with both aluminum alloy and brass nozzles. Aluminum reduces sibilance with added bass; brass enhances mids and treble with clarity. 

Tuning Ear Tips 

Includes three tuning sets — balanced, bass, and deep bass — each available in small, medium, and large sizes. 

2-Pin 0.78mm Cable

The detachable 2-pin design supports 3.5mm and 4.4mm cable upgrades, allowing flexible customization.