Would you spend $1,499 USD on a pair of universal IEMs? Our friends at FiiO have been working on these unique IEMs for over a decade and even if you think it’s slightly over-the-top to spend this level of money on any pair of headphones or earphones, the integration of 3 different types of drivers in the FiiO FX17 is extremely unique.
FiiO’s focus so far in 2025 has been high-performance models like the FT7 planar magnetic headphones that were just shown at CanJam NYC 2025 so it makes sense to them progress to IEMs like this.
A USB-C cable in the box also mean that the FiiO FX17 IEMs can be used with all modern Android and iPhone devices out of the box — but that’s like driving a pair of hybrid MartinLogan Electrostatic Loudspeakers with a $350 Class D amplifier and expecting it to deliver sonic fireworks. As an aside…don’t ever do that with a pair of electrostatic loudspeakers unless you want to witness a different kind of fireworks in your listening space.
The FX17 are designed for a higher end Dongle DAC, desktop amplifier, or DAP if you really want to hear why FiiO spent so much time engineering these.
The quoted frequency response is 8Hz to 40kHz (16 Ohms @1khz, 104dB/mW @1kHz) for those who are curious just what the three different types of drivers are capable of delivering.
3 Kinds of Drivers
The FX17 features a design of 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 driver and ensures each unit operates in its optimal state, resulting in a bigger soundstage and more natural sound.
8 Electrostatic Drivers
Electrostatic drivers have exceptional high-frequency extension easily reaching 50kHz and sense of air that gives the listener a wider and deeper soundstage. Their downside is that their sensitivity is only 99dB/mW, which is low compared to the 110dB/mW sensitivity typically found in balanced armature and dynamic drivers – leading to the ‘masking effect.’
The FX17 uses 8 electrostatic units to increase sound pressure levels in order to make the electrostatic drivers more audibly perceptible as they handle the high and ultra-high frequencies above 6kHz.
4 Custom Knowles BA Drivers
The FIIO FX17 uses Knowles balanced armature driver composite units that handle the mid and high-frequency sounds. Each of the composite balanced armature driver units is divided into two parts, one part responsible for mids and the other for mid-high frequency – leading to denser mids and a more transparent sound and allows them to transition seamlessly into the electrostatic drivers.
To achieve higher flagship-level vocal performance, FIIO, in collaboration with Knowles, custom-developed a ‘Midrange Enhanced Balanced Armature Unit.’ Acoustic vents have been added to the rear cavity of the balanced armature, which provide more sound energy reserves for the mid-frequency balanced armature unit to further tap into the driver’s advantages.
Lithium-magnesium Alloy Diaphragm Dynamic Driver
Lithium-magnesium alloy is lightweight, rigid and has a density of 1.6g/cm³ – making it an ideal material for a dynamic driver diaphragm. When reproducing high-frequency signals with rapid vibrations, the lithium-magnesium alloy diaphragm has excellent mechanical properties thanks to its high internal damping – leading to significantly reduced intrinsic frequency resonance and distortion.
Pure Titanium Construction
The FX17 features a minimalist aesthetic, with a classic and natural curved cavity. The FX17’s ‘ear shell’ cavity is made of high-density, high-strength titanium that is precisely milled from a single block and meticulously hand-polished.
The FX17’s cable utilises three different transmission materials – gold, silver, and copper – in order to take advantage of the strengths offered by the different materials.
The gold, silver and copper are forged at over 1000 degrees and undergo secondary refining to form crystalline monocrystals to remove impurities and reduce transmission loss. Each of the three elements has its own advantages, which together result in significantly improved sound quality.
The titanium construction (minus the cable) and the ear tips weigh 12.2 grams making them rather lightweight.
Connection Flexibility
Included with the FX17 are three swappable audio plugs – 3.5mm single-ended, 4.4mm balanced and a Type-C connector with built-in digital decoding and DSP, allowing you to enjoy high-quality audio no matter the device you are connected to. The Type-C swappable plug features a built-in DSP audio decoding chip that supports up to 32-Bit/384kHz high-resolution PCM.
The supplied cable (1.2 meters) is a 360-wire, 8-strand gold-silver-copper Litz braided cable with MMCX connectors. FiiO also supplies 22 pairs of ear tips with each FX17 including SpinFit, HS18, and HS20 liquid silicone options.
It also supports 8-band high-precision PEQ through FIIO’s proprietary algorithm and the FiiO Control app or web interface, the PEQ allows you to adjust the headphones’ frequency response curve as first seen in the FiiO K17 headphone amplifier.
The Bottom Line
$1,499 is a lot of money for any pair of IEMs (and we’ve seen universal and custom IEMs that are four times the price), but the FiiO appear to be a statement level product from a manufacturer that has proven that it can engineer excellent IEMs at the entry-level and mid-tier price points.
Will Jennings will be reviewing a pair very soon with a wide range of DAPs and Dongle DACs to get a baseline for their performance.
The FiiO FX17 will be priced at £1399 and $1,499 and will be available from April 14th.
For more information: fiio.com/fx17
Where to buy: $1,499 at HiFiGo
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