FiiO JT9 Black Hi-Fi Headphones

Open-Back Planar Magnetic Headphones for Effortless HiFi Listening

The FiiO JadeAudio JT9 Black is an open-back planar magnetic headphone engineered to bring full-size planar performance to a wider audience. Built around a custom 95 x 86 mm driver with a 1 μm PET diaphragm, this over-ear headphone delivers deep bass extension, a wide soundstage, and lightning-fast transients. The JT9 is the right choice for listeners stepping into planar magnetic technology who want a high-resolution, easy-to-drive headphone that works equally well with portable DAC/amps and desktop rigs.

Patented Diaphragm and Magnetic Architecture

What sets this model apart is FiiO's patented sapphire and aluminum dual-coating technology, applied via a 28 nm chip-level vacuum sputtering process. The aluminum layer lowers impedance and improves conductivity, while the sapphire layer increases rigidity for cleaner high-frequency reproduction. A patented uniform magnetic field design with custom curved magnets keeps drive force even across the diaphragm, virtually eliminating split vibrations and keeping distortion exceptionally low.

Technical Specifications

The parameters below define how the JT9 performs in real-world listening — from how easily it pairs with everyday sources to how comfortably it sits during long sessions.

• Driver: 95 x 86 mm planar magnetic with 1 μm PET diaphragm and sapphire/aluminum dual coating
• Frequency Response: 7 Hz – 40 kHz — Hi-Res Audio certified by the Japan Audio Society
• Impedance: 20 Ω at 1 kHz
• Sensitivity: 95 dB/mW at 1 kHz — pairs effortlessly with smartphone dongles and desktop amps
• Weight: ~365 g (excluding cable) with a foldable, multi-axis headband
• Cables Included: 3.5 mm single-ended and 4.4 mm balanced, both 22 AWG oxygen-free copper

Who Is It For

The JT9 is built for music enthusiasts who want planar magnetic sound without committing to a heavy, hard-to-drive full-size headphone. At 365 g and with a 20 Ω / 95 dB sensitivity rating, this model is the right choice for listeners who want a portable-friendly planar that sounds excellent straight out of a phone, dongle DAC, or modest desktop amplifier. Open-back design means it suits quiet, dedicated listening spaces rather than commuting or office use. The included dual-cable bundle (3.5 mm and 4.4 mm) makes it ready for both balanced and single-ended source chains straight out of the box.