FiiO FX17 Hybrid 13-driver flagship in-ear headphones

FiiO FX17 – Flagship Hybrid 13-Driver In-Ear Headphones

- 1DD, 4BA, and 8EST per side
- Eight Sonion electrostatic drivers
- Four custom Knowles BA drivers
- Dynamic driver with 10mm lithium-magnesium alloy diaphragm
- Electronic and physical five-way crossover
- Patented S.Turbo acoustic design
- Titanium construction with gold, silver, and copper cables
- Exclusive serial number nameplate
- Three interchangeable audio plugs included
- 22 pairs of ear tips included, including SpinFit, FiiO HS18, and FiiO HS20
- Hi-Res Audio Certified

What you have in front of you is the masterpiece of FiiO acoustics.
This custom-built acoustic device is the result of 18 years of experience in audio design. It combines the best acoustic technology, embodies a subtle aesthetic, and interprets the ideal sound in your heart.
The essence of 18 years comes together in a creation where all sounds flow seamlessly, just for you.

1DD, 4BA, 8EST design per side
To achieve the best possible sound quality, the FX17 features one dynamic driver, four balanced armature drivers, and eight electrostatic drivers per side.
A five-way crossover has been precisely tuned to balance energy distribution among the drivers and ensure each unit operates at its optimum state, resulting in a wider soundstage and more natural sound.

Eight electrostatic drivers for an airy feel
Electrostatic drivers offer exceptional high-frequency extension, easily reaching 50 kHz, and provide a sense of airiness, giving the listener a wider soundstage.
However, their sensitivity is only 99 dB/mW, lower than the typical 110 dB/mW of balanced armature and dynamic drivers, which can create a masking effect. Therefore, the FX17 uses eight electrostatic drivers per side to increase sound pressure and make the electrostatics audible, handling high and ultra-high frequencies above 6 kHz, not just for show.
The masking effect refers to the phenomenon where human sensitivity to high-frequency signals is reduced in the presence of loud low-frequency signals.

Four custom Knowles BA drivers
The FX17 uses two Knowles balanced armature drivers for mids and highs. Each composite BA driver is divided into two parts: one for mids and one for mid/high frequencies. This produces denser mids, more transparent sound, and a seamless transition to the electrostatic drivers.
For higher flagship-level vocal performance, FiiO developed a Midrange Enhanced Balanced Armature driver with Knowles.
The rear cavity of the BA drivers is designed with acoustic ports to deliver more energy in the midrange, further optimizing driver performance. The result is lush, smooth vocals, making the singer’s voice feel as if it’s right next to you.

Dynamic driver with lithium-magnesium alloy diaphragm, high-resistance material surpassed only by beryllium
Lithium-magnesium alloy is lightweight, stiff, and has a density of 1.6 g/cm³ — ideal for a dynamic driver diaphragm, surpassed only by beryllium.
When reproducing high-frequency signals with fast vibrations, the diaphragm’s high internal damping results in significantly lower natural resonance and distortion, keeping distortion under 0.2% for extremely clean sound.

Patented S.Turbo acoustic design
Inspired by supercar turbos, FiiO developed the patented S.Turbo design, channeling sound through a turbo-shaped structure to boost bass and make it deep and robust.
Excess mid and high frequencies are filtered from the dynamic driver to ensure smooth transitions between lows, mids, and highs, delivering a powerful, full sound.

Resonant cavity and acoustic balance
The FX17’s rear cavity is optimized for sound. Damping with 0.2 mm ports allows precise airflow control, balancing front and rear dynamic driver cavities.
This improves the Q factor and amplitude of the dynamic driver, extends low frequencies, and increases midrange clarity and transparency.

Electronic and physical five-way crossover
On the FX15, a switch allowed turning electrostatic drivers on/off, showing they’re not just decorative but crucial for high frequencies.
The FX17 increases electrostatic drivers handling frequencies above 6 kHz to eight per side, reducing power demands.
A five-way electronic and physical crossover precisely controls the drivers, ensuring a smooth frequency response, flat impedance curve, and balanced energy distribution across volumes.

Pure titanium construction
The FX17 features a minimalist aesthetic, with classic, naturally curved cavities.
Its earcup cavities are high-density titanium, precision-milled from a single block and hand-polished.
Vapor the Position treatment hardens the surface, giving a glossy finish with a beautiful interplay of light and shadow.

Flagship-level ergonomic design
Sonic nozzle angled by 10° — Based on user feedback and research, engineers increased the angle between the sonic nozzle and ear surface by 10° along the Y-axis while keeping nozzle length the same. This improves comfort and stability.
Comfortable fit — The new rear cavity features a 3D shape, especially around the auricle. A 1.4 mm thick filler protrusion matches the human ear, securing the fit.
Reduced ear pressure — The posterior cavity thickness is reduced by ~1 mm in the ear fold area, minimizing pressure and eliminating the feeling of a foreign object in the ear.

Mixed gold, silver, and copper cable
Three materials are used for the FX17 cable: gold, silver, and copper, each chosen for its strengths.
Forged over 1000°C and refined into single crystals to remove impurities and reduce signal loss.
Gold — high conductivity, low resistance, improves bass transients.
Silver — transmits high frequencies better, fast with higher resolution.
Copper — warm and soft tones, natural soundstage.

Three interchangeable in-line audio plugs with twist lock
Included: 3.5 mm single-ended, 4.4 mm balanced, and Type-C with integrated DSP.
The Type-C connector supports 32-bit/384 kHz PCM, balanced output, and 8-band PEQ via FiiO Control App or web interface.
Output power: 2x55 mW @16Ω, 2x30 mW @32Ω
Crosstalk: -110 dB
Noise floor: <0.8 µV
Distortion: <0.001%
SNR: <122 dB

Hi-Res Audio certified
FX17 is Hi-Res Audio certified by the Japan Audio Society (JAS) and Consumer Electronics Association (CEA), ensuring accurate reproduction of sound as intended.

Box contents:

• FX17 in-ear headphones

• 1x headphone cable (gold, silver, copper, interchangeable 3.5 mm, 4.4 mm, and Type-C connectors)

• 1x serial number nameplate

• 2 pairs of foam ear tips (M)

• 3 pairs bass ear tips (S/M/L)

• 3 pairs balanced ear tips (S/M/L)

• 3 pairs vocal ear tips (S/M/L)

• 2 pairs double flange ear tips (M)

• 3 pairs HS20 liquid silicone ear tips (S/M/L)

• 3 pairs SpinFit ear tips (S/M/L)

• 3 pairs HS18 ear tips (S/M/L)

• 1x magnetic cable hanger

• 1x cleaning brush

• 1x MMCX quick release tool

• 1x cleaning cloth

• 1x HB5 carrying bag

• 1x FX17 box

• 1x quick start guide

Specifications:
- Headphone type: Dynamic-BA-Electrostatic hybrid in-ear monitor
- Drivers per channel: 1x 10mm lithium-magnesium alloy dynamic diaphragm, 4x custom Knowles Balanced Armature, 8x Sonion Electrostatic
- Frequency response: 8 Hz – 40 kHz
- Impedance: 16 Ω/mW @1kHz
- Sensitivity: 104 dB/mW @1kHz
- Headphone cable: 8-strand, 360-wire mix of gold, silver, and copper
- Cable length: ~1.2 m
- Single unit weight: ~12.2 g (without cable)
- Connection: extended MMCX
- Audio plug: straight, interchangeable twist-lock