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Fosi Audio i5 Open-Back Planar Magnetic Headphones with 97mm Ultra-Large Diaphragm, CNC Metal & Waln…
Overview
Product Description
Fosi Audio i5
Open-Back Planar Magnetic Headphones for HiFi Audiophiles
Democratizing Planar Sound: Uncompromised Clarity, Comfort & Craftsmanship
The i5 was born from our mission to make planar magnetic headphones more accessible—without compromising on sound quality, comfort, or design. Over a year of in-house development and acoustic tuning led to a headphone that delivers exceptional clarity, low distortion, and lifelike detail.
Transducer Type: Planar Magnetic TransducerMaximum SPL: ≥ 120 dBSPL; Recommended Power: ≥ 500 mWFrequency Response: 10 – 50,000 Hz; THD: < 1% @100dBSPLSensitivity: 98 dB/mW @1kHz; Nominal Impedance: 28 Ω
Immersive Listening, Pure Original Sound
Nano-thin diaphragm symmetrical magnets & precision acoustics deliver high-res, low-distortion sound
97mm Ultra-Large Diaphragm
Nano-precision ultra-thin diaphragm delivers faster, clearer, layered sound.
Symmetrical Arranged High-Strength Magnetic Matrix
44 symmetric N50 magnets ensure ultra-low distortion, delivering pure, natural sound.
Sputtered Coating Technology
1.3μm silver-coated diaphragm via precision sputtering delivers refined, durable sound.
Rigid High-Transparency Acoustic Mesh
Rigid rear mesh ensures stable damping, smooth response,and open soundstage with minimal resistance.
1 Pure Immersion
2 Ultra-Large Diaphragm
3 Magnetic Matrix
4 Sputtered Coating
5 Acoustic Mesh
Durable Memory Metal Headband
High-strength memory metal headband stays shaped, lightweight & flexible for pressure-free comfort.
Dual-Axis Earmuff Arms for a More Precise Fit
Multi-directional rotation adapts to any head shape for secure, custom comfort.
Breathable Skin-Friendly Earpads
Perforated leather & breathable fabric earpads stay cool; memory foam delivers all-day comfort.
Stepless Silicone Adjustment
Silky-smooth silicone slider enables precise, effortless headband adjustments.
1 Memory Metal Headband
2 Dual-Axis Ear Cup Arms
3 Breathable Earpads
4 Seamless Adjust
Ergonomic Design, Long-Lasting Comfort
Ergonomic i5 contours to your head for secure, all-day comfort—music without distraction.
Luxury Craftsmanship, Timeless Elegance
Luxurious materials meet elegant design for timeless sophistication.
Calibrated in Pro Studio for Pure Reference Sound
Pro-tuned for pure studio sound. i5 delivers reference accuracy with planar precision.
Ultimate Hi-Fi Stack: DAC+Amp+i5 Headphones
DAC+Amp+i5 headphones deliver pristine audio & endless musical immersion with studio-grade precision
1 Ergonomic Design
2 Refined Craftsmanship
3 Studio-Tuned Precision
4 Endless Audio Bliss
Q&A
1. What should I do if there is an unusual noise using the i5?
A. Disconnect the cable and shake gently to check for any persistent noise. If it continues, please contact our support team. B. Try different recordings to ensure the issue isn’t with the quality of the recording. C.Test with another source device to check if the source device is faulty.
2. How should I store the i5 when not in use?
A. Avoid storing in humid environments for extended periods. B.Keep the i5 away from places where it might fall off. C.Keep the i5 away from high-temperature areas.
3. What precautions should l take when using the i5?
A. Avoid compressing the ear pads hard. B. Do not press or poke the interior of the ear pads with fingers to prevent damage to its planar driver. C. Do not wear metal earrings or similar items while using the i5, as it contains magnets. D. Do not use speaker amplifiers to drive the i5.
4. Is burn-in necessary for the i5?
Burn-in is not mandatory for i5. Normal use over time may stabilize the diaphragm and enhance the sound performance, particularly in terms of bass extension and detail clarity. However, this process is not essential for sound quality.
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Customer Reviews
4.5 out of 5 stars 182
4.4 out of 5 stars 60
4.2 out of 5 stars 1,122
4.5 out of 5 stars 2,975
4.4 out of 5 stars 217
4.2 out of 5 stars 587
4.2 out of 5 stars 587
Price
£179.99£179.99
£159.99£159.99
£79.99£79.99
£69.99£69.99
£99.99£99.99
£79.99£79.99
£63.99£63.99
Type
Balanced Stereo DAC
Balanced HiFi Preamplifier
DAC+Headphone Amp
DAC+Headphone Amp
Headphone Amp+Equalizer
DAC+ Headphone Amp
DAC+ Headphone Amp
MAX Power Output
XLR: 5Vrms/RCA: 2.5Vrms
–
500mw@32Ω
250mw@32Ω
3.5MM: 280mW/4.4MM: 1100mW@32Ω
120mW(SE); 220mW(BAL)
130mW(SE); 510mW(BAL)
Input
USB+HDMI+OPT+COA+BT
RCA/XLR
USB-C+OPT+COA+3.5mm Microphone
PC-USB + Optical + Coaxial
USB/OPT
Type C
Type C
Output
XLR + RCA
RCA/XLR/SUB
RCA + 3.5mm Headphone
RCA + 3.5mm Headphone
3.5mm/4.4mm HP+3.5mm AUX/OPT
3.5mm + 4.4mm Headphone
3.5mm + 4.4mm Headphone
Treble & Bass Control
✘
✔
✔
✔
✘
✘
✘
THD
<0.00008%
≤0.0008%(SE)/≤0.0007%(BAL)
<0.003%
≤0.01%
≤ 0.001%
≤ 0.0006%(SE) ≤ 0.001%(BAL)
≤ 0.0002%(SE) ≤ 0.001%(BAL)
SNR
126dB
≥115dB(SE)/≥112dB(BAL)
>110dB
>105dB
3.5mm: 120dB/4.4mm: 115dB
≥120dB
≥130dB
Terminating Impedance
No Headphone Output
–
16-300 Ohms
16-200 Ohms
16-300 Ohms
16-300 Ohms
16-300 Ohms
Work Voltage
DC 12V
Power Cable
DC 5V
DC 5V
DC 5V
DC 5V
DC 5V
Package Dimensions : 31.4 x 26.7 x 16.7 cm; 1.63 kg
Date First Available : 25 July 2025
Manufacturer : Fosi Audio
ASIN : B0FJX4CG4M
Item model number : I5
Country of origin : China
Guaranteed software updates until : unknown
Best Sellers Rank: 11,334 in Musical Instruments & DJ (See Top 100 in Musical Instruments & DJ) 77 in Studio Headphones
Customer reviews: 3.0 3.0 out of 5 stars 2 ratings
Immersive Listening, Pure Original Sound : Experience high-fidelity sound with nano-thin diaphragm and symmetrical magnets. Precision acoustics deliver high-resolution, low-distortion sound for live-performance realism
97mm Ultra-Large Diaphragm : 97mm Nano-Level driver at 2μm thickness reveals microscopic details. Sputtered silver alloy coating enhances clarity while ensuring long-term sonic consistency and durability
Ergonomic Design, Long-Lasting Comfort : Memory metal headband with multi-axis pivoting earcups adapts instantly. Silicone sliders enable micro-adjustments. Breathable skin-friendly earpads eliminate fatigue during extended sessions
Refined Craftsmanship : Handcrafted walnut wood chambers paired with CNC-milled aluminum frame. Genuine sheepskin headband and signature S-design accents exude understated luxury and timeless sophistication
Precision Magnetic Control : 44 N50 neodymium magnets ensure fast transient response. Acoustically transparent open-back grille minimizes resonance for expansive, holographic soundstage with studio-grade accuracy