The Fosi Audio i5 Open-Back Planar Magnetic Headphones combine ultra-large 97mm drivers, a 2μm nano-thin diaphragm, and 44 N50 neodymium magnets for exceptional clarity, detailed sound, and precise imaging. Premium walnut wood chambers, CNC-machined aluminum construction, and an ergonomic headband deliver refined craftsmanship and lasting comfort. Featuring a spacious open-back soundstage and extended 10Hz–50kHz frequency response, the i5 is an excellent choice for audiophiles seeking an immersive high-fidelity listening experience.
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Fosi Audio i5 Open-Back Planar Magnetic Headphones

Experience exceptional detail, natural sound, and premium craftsmanship with the Fosi Audio i5 Open-Back Planar Magnetic Headphones. Designed for audiophiles and critical listeners, the i5 combines an ultra-large 97mm planar magnetic driver, an advanced 2μm nano-thin diaphragm, and a precision-engineered magnetic system to deliver outstanding clarity, fast transient response, and low distortion. Its open-back design creates a spacious, immersive soundstage that brings out the subtle textures, instrument separation, and dynamics of your favorite recordings.

At the heart of the Fosi Audio i5 is an advanced planar magnetic transducer featuring a magnetron-sputtered silver alloy conductive layer and 44 high-strength N50 neodymium magnets. This sophisticated driver architecture provides precise diaphragm control across an extended 10Hz–50kHz frequency response, reproducing everything from deep bass notes to delicate high-frequency details. The acoustically transparent rear grille minimizes unwanted resonance and acoustic resistance, allowing music to sound open, natural, and remarkably lifelike.

Premium materials and thoughtful ergonomics make the i5 equally impressive in design and comfort. Handcrafted walnut wood chambers complement a CNC-machined aluminum frame, while a flexible memory-steel headband, genuine sheepskin headband covering, and multi-axis adjustable earcups provide a secure, adaptable fit. Breathable, cushioned ear pads and precision silicone adjustment sliders help distribute pressure comfortably during extended listening sessions. With a 28-ohm impedance and 98dB/mW sensitivity, the i5 is compatible with a variety of headphone amplification setups, although Fosi Audio recommends at least 500mW of output power for optimal performance.

Specifications

• Brand: Fosi Audio
• Model: i5
• Product Type: Over-ear planar magnetic headphones
• Acoustic Design: Open-back
• Driver Type: Planar magnetic transducer
• Driver Size: 97mm
• Diaphragm Thickness: 2μm ultra-thin diaphragm
• Diaphragm Technology: Nano-thin diaphragm with magnetron-sputtered silver alloy conductive coating
• Conductive Layer: Approximately 1.3μm silver metal voice coil coating
• Magnetic System: 44 N50-grade neodymium magnets total, with 22 magnets per driver
• Frequency Response: 10Hz–50kHz
• Nominal Impedance: 28 ohms
• Sensitivity: 98dB/mW at 1kHz
• Maximum Sound Pressure Level: ≥120dB SPL
• Total Harmonic Distortion: Less than 1% at 100dB SPL
• Recommended Amplifier Power: ≥500mW
• Headphone Construction: Handcrafted walnut wood chambers and CNC-machined aluminum frame
• Rear Grille: Acoustically transparent rigid open-back mesh
• Headband: Flexible memory-steel construction with genuine sheepskin covering
• Headband Adjustment: Precision silicone adjustment sliders
• Earcup Design: Multi-axis pivoting earcups
• Ear Pads: Breathable cushioned pads with memory foam
• Approximate Weight: 550g
• Connectivity: Wired
• Included Cable: 3.5mm headphone cable
• Included Adapter: 6.35mm headphone adapter
• Additional Included Accessories: User manual

What It's Great At

• Ultra-Large 97mm Planar Magnetic Drivers: Advanced planar magnetic transducers with ultra-thin diaphragms deliver exceptional resolution, accurate instrument separation, and fast transient response for detailed, engaging music reproduction.
• Expansive Open-Back Soundstage: An acoustically transparent rear grille reduces unwanted resonance and allows sound to develop naturally, creating an open and immersive presentation with excellent spatial imaging.
• Precision Magnetic System: A symmetrical arrangement of 44 N50 neodymium magnets provides precise diaphragm control, reducing nonlinear distortion and preserving delicate musical details.
• Advanced Silver Alloy Diaphragm Coating: Magnetron-sputtered conductive material helps improve signal responsiveness, sound clarity, and long-term driver consistency.
• Premium Walnut and Aluminum Construction: Handcrafted walnut chambers, CNC-machined aluminum components, and refined finishing details combine durability with a sophisticated audiophile aesthetic.
• Designed for Extended Listening: A flexible memory-steel headband, multi-axis pivoting earcups, adjustable silicone sliders, and breathable cushioned ear pads create an adaptable fit for longer listening sessions.
• Extended Frequency Reproduction: A wide 10Hz–50kHz frequency response supports deep low-frequency extension, articulate midrange reproduction, and detailed high-frequency performance.
• Excellent for Dedicated Hi-Fi Systems: The i5 is well suited to desktop DAC and headphone amplifier setups, with Fosi Audio recommending at least 500mW of amplifier power for optimal results.

FAQ Section

Q: What type of headphones are the Fosi Audio i5?
A: The Fosi Audio i5 are wired, open-back, over-ear planar magnetic headphones designed for high-fidelity music listening. They feature large 97mm planar drivers that deliver detailed sound, fast transient response, and a spacious listening experience.

Q: What are the benefits of planar magnetic drivers?
A: Planar magnetic drivers use a thin diaphragm controlled by a magnetic field to reproduce sound with precise movement and low distortion. The i5 uses a 2μm ultra-thin diaphragm and 44 N50 neodymium magnets to reproduce subtle musical details, accurate instrument separation, and controlled dynamics.

Q: Do the Fosi Audio i5 headphones need an amplifier?
A: A dedicated headphone amplifier is recommended for optimal performance. Although the i5 has a nominal impedance of 28 ohms and a sensitivity of 98dB/mW, Fosi Audio recommends an amplifier capable of delivering at least 500mW of output power.