FiiO FT15

Open-Back Planar Headphones 

• 800nm ultra-thin diaphragm
• Diamond-coated diaphragm
• Proprietary planar technology
• 101mm large planar driver
• Patented uniform magnetic field design
• 28nm chip-grade manufacturing process
• 95dB/mW high-sensitivity easy-to-drive design
• Lightweight 425g construction
• Premium North American walnut wood ear cups
• Liquid-nitrogen-treated 6N monocrystalline copper cable
• 2 pairs of tuning ear pads included
• Custom Yaoli linen headphone storage case included 

Proprietary Planar Technology

Building on the foundation established by the pioneering FT5, the FT15 brings a new evolution of planar design.

It features a groundbreaking 800nm ultra-thin diaphragm and FIIO's first diamond-coating process, capturing even the finest nuances in the music. A specially refined patented magnetic circuit applies force to the diaphragm more evenly and powerfully, reducing vibrational distortion. The result is deep, solid bass, refined and easy-to-listen mid-to-high frequencies, and an overall warm, natural sound.

At the same time, the FT15 combines high sensitivity and easy drivability with a lightweight design, delivering not only outstanding sound but also a more relaxed, comfortable experience for long listening sessions.

101mm Large Driver

The effective vibrating area of a diaphragm directly dictates bass energy density and soundstage scale. Equipped with a massive 101mm full-size driver, the FT15 boasts an effective vibrating area of 6,443.5mm², an impressive 35% increase over the previous-generation FT5. This abundant energy reserve equips the FT15 with exceptional dynamic impact and sub-bass reach. When rendering grand dynamic pieces like full-scale symphonies, it presents a wider, more natural horizontal soundstage while effortlessly managing rapid dynamic swings.

800-Nanometer Ultra-Thin Diaphragm

FT15's diaphragm thickness drops from the previous generation's 6 microns to a breakthrough 800 nanometers, 86.7% thinner than its predecessor. This nanometer-scale thinness approaches the physical limits of the material, representing the current state of the art in the industry. A thinner diaphragm means better sound, across the board.

With nanometer-level diaphragm precision, the FT15 achieves faster transient response. Even subtle signals in the high and ultra-high frequencies can be reproduced with greater precision and accuracy.

The diaphragm follows the signal closely and moves with precision, starting and stopping in sync with the signal with minimal residual ringing. The result is an exceptionally clean and refined sonic character.

The ultra-thin diaphragm delivers greater compliance and lower distortion, producing smooth, refined highs that remain comfortable even over long listening sessions.

Innovative Diamond Coating

The FT15 incorporates FIIO's self-developed patented multi-layer coating technology (patent number ZL2024205488218). The voice coil features a silver-aluminum alloy coating to enhance its mechanical performance and conductivity, while the diaphragm employs an innovative full-surface diamond coating. Using a highly sophisticated manufacturing process, this design brings the unique physical properties of diamond into the acoustic field.

The diamond material used in FT15's coating offers greater hardness and structural stability, the same properties that make it a common choice for tweeter diaphragms in high-end loudspeakers. Applied through a vapor deposition process, this coating forms a stable reinforcing layer on the diaphragm that reduces high-frequency breakup and improves response speed, extending frequency response up to 40kHz. Because the coating resists decomposition and fatigue even under prolonged vibration, it maintains consistent acoustic performance over the long term. A vacuum high-temperature treatment further tunes the substrate's natural frequency, lowering its resonance point for deep, powerful bass extension.

Patented Uniform Magnetic Field Design

Traditional rectangular magnet designs create uneven magnetic field distribution, which can often lead to diaphragm breakup vibration and distortion, compromising the sound. The FT15 features FIIO's specially developed patented uniform magnetic field technology (patent number ZL202420884963.1), combining custom-shaped high-strength magnets with precisely optimized magnetic circuit alignment to create a highly uniform magnetic field. By driving the diaphragm evenly and synchronously across its entire surface, the design helps suppress breakup vibration and distortion at the source, faithfully preserving the details of the original sound.

The FT15 magnets are precisely tuned through finite element analysis. Magnetic flux is distributed more evenly, the effective field covers a wider area, and the coil driving area is greatly increased. The diaphragm is driven more fully, raising driver sensitivity. Along the diaphragm's direction of motion, the magnetic field remains highly consistent. At different excursion levels, force on every part of the coil stays even. Nonlinear breakup is suppressed at the source, and harmonic distortion is significantly reduced.

28nm Chip-Grade Manufacturing Process

Conductive coils have long had a weakness: they fatigue and break down over time. FT15 solves it by borrowing a precision process straight from the semiconductor industry. Through vacuum electroplating, the voice coil is uniformly formed on the diaphragm, greatly strengthening the bond between the conductive layer and the diaphragm substrate. The structure remains firmly bonded and stable through prolonged vibration, improving the synchronization of diaphragm movement while maintaining greater consistency and stability in sound performance over time. Proven across multiple products, this process brings the likelihood of vibration-induced coil damage close to zero.

95dB/mW High-Sensitivity, Easy-to-Drive Design

The FT15 incorporates a dual-sided heterogeneous magnet array, leveraging finite element analysis to optimize magnetic field distribution. This keeps the voice coil positioned within the strongest region of the magnetic field for ample driving force. The FT15 can be easily driven by portable players and dongle DACs, bringing you a full, solid sound wherever and whenever you listen.

425g Lightweight Design

To overcome the traditionally heavy weight of planar headphones, the engineers carefully optimized the material selection, structural design, magnetic circuit, and other aspects of the FT15, bringing the total weight down to 425g, significantly lighter than comparable planar headphones. Less weight, without compromising quality.

The FT15 uses premium carbon fiber for the headband, a material that is both costly and difficult to process, taking advantage of its low weight, high rigidity, and toughness. Combined with an optimized structural design, it helps solve the problems of excessive weight and unwanted twisting or deformation.

The high-end specialty modified plastic magnet bracket matches aluminum alloy for rigidity but weighs in at just two-thirds the density, delivering all the magnetic-circuit strength FT15 needs, at a fraction of the weight. The dual-sided heterogeneous magnetic circuit also reduces magnet weight compared with conventional designs while maintaining ample magnetic driving force.

Premium North American Walnut Wood Ear Cups

The FT15's center frame is crafted from North American FAS-grade black walnut, a wood commonly used in luxury car interiors, fine furniture, and premium musical instruments. Each pair is meticulously finished and polished to preserve the wood's natural grain, resulting in a piece that's as much a collectible as it is a pair of headphones, where musical craftsmanship meets fine woodworking.

FAS (Firsts and Seconds) is a top-tier grading standard used in the North American hardwood industry, denoting timber that has passed rigorous quality screening. Compared to standard-grade wood, FAS-grade black walnut offers more consistent grain patterns, fewer natural imperfections, and greater workability.

Liquid-Nitrogen-Treated 6N Monocrystalline Copper Cable

The FT15 uses 6N OCC single-crystal copper with a purity of up to 99.99998%, offering no grain boundaries, low resistance, and high electrical conductivity. These properties help reduce interference from oxygen and hydrogen impurities during signal transmission. Each conductor undergoes 100+ hours of -192°C liquid-nitrogen cryogenic treatment, releasing internal metal stress and optimizing its microscopic structure. This allows the signal to travel with effortless smoothness and revealing clearer, more distinct sound. The FPA insulation further applies a subtle tuning to the mid-low frequencies, adding just the right amount of coloration so the timbre comes through transparent yet open and relaxed.

The cryogenic treatment applies to the core copper conductor only, not the cable's outer protective jacket.

A Comprehensive Set of Premium Accessories

Two sets of ear pads are included. The suede ear pads are highly durable, deepen the bass, and add warmth to vocals, with a smooth, non-fatiguing top end, ideal for pop and vocal-focused music. The protein leather ear pads enhance high-frequency resolution and vocal clarity, well suited to classical instrumental music and female vocal tracks.

Included as standard are a 4.4mm balanced headphone cable, a 4.4mm-to-6.35mm adapter, and a 4.4mm-to-XLR-4 balanced adapter, giving you more ways to connect, upgrade, and enjoy the FT15.

The FT15 comes with a premium, custom Yaoli storage case, made with the same materials and craftsmanship you'd find in high-end French luxury goods. Durable and elegant, it keeps your headphones beautifully protected wherever you take them.

Hi-Res Audio Certified

The FIIO FT15 is certified for high-quality audio by the Japan Audio Society (JAS), accurately reproducing high-fidelity sound to deliver an authentic, true-to-life listening experience.