Fosi Audio IM4 Open-Back IEMs: A Detailed Overview of Their Affordable, High-Quality Features
By HiFi Editorial24 February 2026
Key Highlights
Fosi Audio introduces its IM4 Open-Back IEMs, featuring a 10mm beryllium diaphragm for a natural and detailed sound profile.
The IM4 is equipped with an N52 dual-magnet system and dual-chamber acoustic design for enhanced frequency balance and reduced distortion.
Users can customize their listening experience with interchangeable aluminum and brass nozzles and three ear tip sets: balanced, bass, and deep bass.
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