FiiO FT1 Pro Open-Back Planar Magnetic Headphones

The FiiO FT1 Pro is an open-back planar magnetic headphone built around FiiO’s second-generation, self-developed 95 × 86mm planar driver, with specifications that FiiO says rival flagship planars. Its 1µm diaphragm carries a patented sapphire and aluminium dual coating applied with a 28nm-grade process, and a patented uniform magnetic field keeps it moving evenly. At 20Ω and 112dB/Vrms it is easy to drive, it weighs only 374g, and it comes with 3.5mm and 4.4mm balanced cables and a storage bag. It won a CIHE EHA 2024 Gold Award and a VGP 2025 Summer Life Style award.

FiiO’s own driver, designed from the ground up

FiiO designed every part of the driver: the diaphragm, the patented dual coating, the width of the conductive traces, the tuning of the magnetic circuit and even the standardised bracket fixings. Unlike an off-the-shelf driver, a self-developed one lets FiiO build a complete acoustic system around it, so the FT1 Pro can be light and still sound great, with a large, almost limitless soundstage that FiiO says is rare among its peers, and effortless extension up to 40kHz.

A class-leading 1µm diaphragm

After two years of research and development, FiiO created a 1µm diaphragm on a high-performance PET substrate. Even the difference between 2µm and 1µm is noticeable when the film vibrates at high speed: the lighter diaphragm responds with lightning speed, reproduces subtle ultra-high frequencies faithfully and gives exceptional dynamic range.

Sapphire and aluminium: a patented dual coating

FiiO’s patented dual-coating system (patent ZL2024205488218) applies two materials to the PET film. The first layer, aluminium, is light and conductive: it improves the traces’ conductivity, lowering the impedance and the power the driver needs, and improves dynamics. The second, sapphire, is very hard: it stiffens the diaphragm, improving treble resolution and overall transparency and giving the driver a distinctive sound. As Joseph, chief engineer of FiiO’s IEM R&D centre, puts it: “Each material has its own natural frequency and timbre. Pairing different materials… leads to a rich variety of sonic experiences.”

A patented uniform magnetic field

In a conventional planar, adjacent magnets create a field that is strong in some places and weak in others, as FiiO’s finite element simulations show, so the trace is pushed unevenly, raising the risk of break-up and distortion. FiiO’s patented design (ZL202420884963.1) gives the magnets rounded corners, which expands and evens out the field. The diaphragm is driven evenly across its surface, for less distortion and a more refined sound that captures the subtlest nuances.

Made with a 28nm-grade process, twice

A driver this intricate needs nanometre-level precision that traditional coating methods can’t reach. FiiO uses a 28nm-grade process inspired by semiconductor manufacturing: in a vacuum of 6.6 × 10⁻³ Pa at 120°C, the trace material is ionised and built up on the 1µm film to the ideal thickness, which also makes the traces much more durable. The FT1 Pro goes beyond industry practice by running this rigorous process twice on each diaphragm, once for each coating. The FT5’s traces, made the same way, passed more than six months of ageing tests in FiiO’s labs with no detachment, separation or breakage.

Easy to drive, wide frequency response

The FT1 Pro is designed to give great planar sound without serious amplification: its 20Ω impedance and high sensitivity of 112dB/Vrms (95dB/mW) at 1kHz mean a good portable player or dongle can drive it, and its frequency response runs from 7Hz to 40kHz.

Light, adjustable and comfortable

Despite its large, double-sided-magnet driver, the FT1 Pro weighs only about 374g. The headband slides on high-quality steel rails that add durability and a precise feel, with a stamped scale from 0 to 11 (12 positions, 38mm of travel), a wider range than similar headphones, and a soft suede cushion where it touches your head. The three-axis adaptive design (35° horizontal and 45° pitch rotation) lets the earcups follow the shape of your head for comfort and a good seal.

The breathable fabric ear pads have a textile face in a high-density mesh that carries heat away on long sessions, with protein leather around the sides.

Two cables and a storage bag

The FT1 Pro uses common dual 3.5mm headphone connectors, so the cable is easy to change or upgrade. Two cables come in the box, one with a 3.5mm single-ended plug and one with a 4.4mm balanced plug. Both are 1.5m long, 24AWG, made from 392 strands of silver-plated oxygen-free copper, for a transparent yet robust sound. The storage bag is made with the same techniques and materials used by high-end French brands, something rarely included in this class.

Good to know

• Open-back: sound leaks in and out, so the FT1 Pro is best for listening at home. For a closed-back option, see the FiiO FT13.
• FiiO’s flagship planar, with a 106mm driver and gold and silver coating, is the FT7.
• In the box: FT1 Pro, 3.5mm and 4.4mm cables, 3.5mm to 6.35mm adapter, storage bag and quick start guide.