The FiiO FT5 is FiiO's first full-size planar magnetic headphone, sitting below the flagship FT7 in the company's over-ear range. It brings the resolving character and low-distortion performance of planar magnetic technology to a price point previously occupied by dynamic driver designs, and crucially does so without the high-impedance, low-sensitivity drawbacks that have traditionally made planar headphones challenging to drive from portable sources.
90mm Planar Magnetic Driver
The core of the FT5 is a large 90mm planar magnetic driver using a PAR diaphragm and aluminium alloy coils. The diaphragm is processed to approximately 6 microns in thickness using a 28nm chip-scale process. Where a conventional dynamic driver concentrates movement at a single coil point, the planar driver distributes the driving force evenly across its entire surface, reducing the uneven vibration modes that cause high-frequency distortion in dynamic designs. FiiO uses nano-level aluminium alloy coating on the coils, chosen to reduce moving mass while maintaining good conductivity, which contributes to both the driver's sensitivity and its high-frequency detail.
Magnet Array
Each driver is flanked by 20 N52 neodymium magnets per channel (11 on the inner face and 9 on the outer) with a magnetic flux density of up to 1.5T. The asymmetric count is deliberate: the arrangement balances the magnetic forces acting on the diaphragm from either side, allowing it to move consistently and reducing distortion at higher output levels. With 40 magnets in total across the headphone, the motor system is substantial, yet the FT5 achieves a sensitivity of 110dB/Vrms (96dB/mW) at 1kHz, making it driveable from quality portable players as well as desktop amplifiers.
Open-Back Acoustic Design
The FT5 uses a fully open-back construction. The rear grille is designed to control airflow as the driver moves, managing the behaviour of rear-wave radiation to reduce resonances and support a wide soundstage. The open design also contributes to the natural, low-compression character that planar magnetic headphones are associated with, though it does mean the FT5 is intended for home or studio listening rather than commuting.
Lightweight Magnesium Aluminium Alloy Construction
The shell of the FT5 is fabricated from a magnesium aluminium alloy, which is considerably less dense than standard aluminium alloy, reducing the total weight of the headphone. At approximately 456g (excluding cable), the FT5 is competitive for a headphone with 40 N52 magnets and a 90mm driver assembly. The dual-rail headband distributes the weight across a broad area of the crown.
Cable and Connectivity
The FT5 uses a detachable cable terminating at the headphone end in dual 3.5mm mono jacks (one per ear). The included cable is 1.5m in length, constructed from 392 strands of high-purity silver-plated monocrystalline copper, and ships with a 4.4mm Pentaconn balanced plug pre-installed. Three further options are also included: a 3.5mm single-ended plug, a 6.35mm male to 3.5mm female adapter, and an XLR-4 male to 4.4mm female balanced adapter, providing compatibility with the full range of headphone amplifier terminations.
In the Box
The FT5 is supplied with two sets of ear cushions (one pair in protein leather, one pair in velour), the detachable cable, four swappable audio plugs, a hard-shell carry case, a soft storage pouch, and documentation.