The FiiO FH9 is FiiO's flagship in-ear monitor, sitting at the top of the company's FH hybrid series. Designed for discerning listeners seeking high-resolution audio in a portable form factor, the FH9 combines a bespoke 13.6mm dynamic driver with six genuine Knowles balanced armature drivers in a hand-finished pure titanium alloy shell.
Hybrid Driver Architecture
The FH9 employs a total of seven drivers per earphone: one 13.6mm dynamic driver featuring a second-generation DLC (Diamond-Like Carbon) diaphragm for extended bass and midrange performance, paired with six Knowles balanced armature drivers arranged in a three-way crossover configuration. Two 60235 dual Knowles BAs handle midrange and upper midrange, while one 31736 dual Knowles BA manages high-frequency reproduction. This arrangement allows each driver to operate in the frequency range where it performs best.
Knowles Balanced Armature Technology
Knowles is the world's leading manufacturer of balanced armature transducers, and the components used in the FH9 are professional-grade units drawn from Knowles' precision hearing instrument range. Balanced armature drivers operate on a fundamentally different principle to dynamic drivers: a miniature armature is suspended between two magnets and deflects in response to the audio signal, driving a thin diaphragm. This mechanism produces extremely detailed high-frequency reproduction with very low distortion, and the compact dimensions of balanced armature drivers allow multiple units to be integrated into a small earphone housing without compromising the acoustic design.
Titanium Alloy Construction
The FH9 shell is machined from pure titanium alloy, which FiiO chose for its exceptional rigidity and very high internal damping compared to aluminium or resin. The titanium construction minimises acoustic resonance within the housing, preventing the earphone body itself from colouring the sound. The Black version features a smooth gloss finish with gold accents, giving a premium appearance that reflects its position as a flagship product.
Replaceable Sound Filters and Cable
Three sets of replaceable acoustic filters are included: Green for a balanced tuning, Black for a neutral response, and Red for enhanced treble. These screw into the nozzle and allow the listener to adjust the sound signature to suit personal preference or source material. The FH9 ships with an 8-strand, 224-wire per strand, high-purity monocrystalline pure silver cable terminating in a standard MMCX connector. Three swappable termination plugs are included: 2.5mm balanced, 3.5mm single-ended, and 4.4mm balanced, covering every common portable and desktop amplifier output.
Accessories
The FH9 ships with FiiO's HB5 hard-shell carry case and an extensive selection of ear tips: three sizes each of Bass, Balanced, and Vocals ear tips, foam tips, double-flange tips, and SpinFit tips. A cleaning brush, MMCX removal tool, and magnetic cable management clamp are also included.
