FiiO's planar line has been climbing in driver size for three years. The FT15 ends the climb at 101 mm, and the interesting number isn't the diameter: it's 800 nanometres.
That's the thickness of the diaphragm, 86.7% thinner than the one in the previous generation, and across its whole face FiiO has laid down a diamond coating by vapour deposition. Thinner moves faster. Coated stays rigid. The pair of them is what lets the FT15 hold its response out to 40 kHz instead of breaking up on the way there.
It lands at €499, with walnut earcups, a carbon fibre headband, and a spec sheet that says something unusual for a full-size planar: you can drive it from a dongle.
What the 101 mm driver actually buys you
Effective radiating area is 6,443.5 mm², which FiiO puts at roughly 35% more moving surface than the previous generation. More area moving air at lower excursion is the classic route to a stage that sounds wide rather than loud, and it's the reason people put up with full-size planars in the first place.
The supporting work is where FiiO spent the engineering budget:
- Full-face diamond coating. Applied by vapour deposition, it stiffens the diaphragm without adding meaningful mass, which is what pushes the breakup point above the audible band and extends response to 40 kHz.
- Patented uniform magnetic field. Custom contoured high-strength magnets drive the diaphragm evenly across its surface instead of harder at the centre, cutting distortion at the source rather than voicing around it.
- 28 nm electroplated voice coil. A chip-grade process with a silver-aluminium alloy coating, aimed at a coil that stays mechanically stable over years of use.
The dongle-friendly part
24 Ω and 95 dB/mW. That combination is the headline for anyone who has bought a big planar and then discovered they also needed to buy an amplifier. A USB dongle with a 4.4 mm output gets the FT15 to listening level, and a modest desktop amp has it comfortably handled. You can spend more on the chain later, but you don't have to on day one.
Walnut, carbon fibre, 425 g
The earcups are North American FAS-grade black walnut, the top grade in the hardwood trade, which means consistent grain and few natural flaws. The headband is carbon fibre, and the total is 425 g without the cable. For a full-size planar with 101 mm drivers that is genuinely light, and the 3.8 N clamping force suggests FiiO is aiming at long sessions rather than a tight seal it doesn't need on an open-back anyway.
The cable is 6N monocrystalline copper at 99.99998% purity, cryogenically treated for over 100 hours at −192 °C, terminated in 4.4 mm balanced with dual 3.5 mm TS connectors at the cups. Two sets of earpads ship in the box: suede fitted from the factory for warmth and bass weight, protein leather for extra treble resolution. Swapping them is the tone control.
What the launch coverage flagged
The FT15 is new enough that full reviews haven't landed yet, so treat everything below as launch coverage rather than verdicts. TechRadar filed it under "our favorite budget audiophile brand launches new flagship planar magnetic headphones that aren't so budget", which is the honest read: FiiO built its name under €200, and this is the model where it stops being the cheap option. What Hi-Fi? led on the diamond coating and the open, spacious soundstage FiiO is claiming for it. We'll update this post once we've had a pair on the bench.
Quick specs
| Price (incl. VAT) | €499 |
| Type | Full-size open-back planar magnetic |
| Driver | 101 mm planar, 6,443.5 mm² radiating area, 800 nm diamond-coated diaphragm |
| Frequency response | 7 Hz to 40 kHz |
| Impedance | 24 Ω at 1 kHz |
| Sensitivity | 95 dB/mW, 111 dB/Vrms |
| Weight | 425 g without cable |
| Clamping force | 3.8 N ±0.3 N |
| Cable | 1.5 m, 6N monocrystalline copper, dual 3.5 mm TS to 4.4 mm balanced |
| In the box | XLR-4 and 6.35 mm adapters, suede and protein leather earpads, fabric case |
Who it's for
Buy it if you want flagship planar scale at home without building an amplifier chain around it, if you already run a 4.4 mm balanced source, or if you like the idea of tuning the sound by swapping pads rather than buying an EQ.
Look elsewhere if you need isolation. Open-back leaks in both directions, so this is a room headphone, not an office or commuting one. And note there's no 3.5 mm single-ended cable in the box: the FT15 ships balanced, with adapters to 6.35 mm and XLR-4, so a 3.5 mm source needs an adapter you supply.
Pre-order and availability
The FT15 is €499 at Soundium, expected in October 2026. Pre-orders are open now and the EARLY5 code takes 5% off.
Not sure whether the FT15 or the FT7 is the right end of the FiiO planar range for your setup? Talk to the Soundium team before you order.
Soundium