FiiO's $499 FT15 Succeeds the FT5 With a 101mm Planar Driver and an 800-Nanometre Diaphragm

FiiO announced the FT15 on 17 September 2026, an open-back planar magnetic headphone positioned as the successor to the FT5. The headline change is size: the planar driver grows from the FT5's 90mm to 101mm, and the diaphragm suspended inside it drops from 6 microns to 800 nanometres, with a diamond coating applied across its full face. US price is $499.

Both eCoustics and Major HiFi describe the FT15 as taking over from the FT5 in FiiO's line, and Darko.Audio framed it the same way. None of the sources says FiiO has stopped selling the FT5, so treat this as a succession rather than a discontinuation.

A bigger driver, and a much thinner diaphragm

The 101mm figure is a diameter, and it is worth separating that from the other number FiiO is promoting. Major HiFi puts the effective radiating area at 6,443.5mm², and eCoustics characterises the change as roughly 35% more active diaphragm area than the FT5. So: an 11mm increase in diameter, and about a third more working surface. The two figures describe the same driver from different angles rather than stacking on top of each other.

The diaphragm itself is the more dramatic spec. At 800 nanometres it is 86.7% thinner than the 6-micron film used in the FT5 — a reduction FiiO states directly, and one that holds up arithmetically when you convert 6 microns to 6,000 nanometres. Thinner diaphragms mean less mass for the magnetic field to move, which is the usual engineering argument in planar design, though the counterpart is that a thinner film needs help staying rigid. FiiO's answer here is a full-face diamond coating rather than a partial or patterned one.

Around the diaphragm, FiiO describes a patented dual-sided magnetic array built from custom-contoured high-strength magnets, with the stated aim of distributing driving force evenly across the whole diaphragm surface rather than concentrating it. That is the manufacturer's own description of the design intent, not a measured result. The same caution applies, more strongly, to FiiO's description of the electroplated voice coil using "28nm" chip-grade terminology — 28nm is semiconductor process nomenclature, and its application to a headphone voice coil is FiiO's marketing language rather than an independently meaningful dimension.

The electrical numbers

The FT15 is rated at 24 ohms impedance and 95dB/mW sensitivity, figures both sources agree on. eCoustics reports that the FT15 is easier to drive than the FT5 and workable from portable players rather than demanding a dedicated desktop amplifier — a claim that sits consistently alongside a 24-ohm, 95dB/mW rating, but one that originates with FiiO and eCoustics rather than from independent bench testing. As with everything else in this announcement, nobody outside FiiO has measured or listened to the FT15 yet.

Walnut, carbon fibre and 425 grams

Physically, the FT15 leans on natural materials. The earcups are turned from North American FAS-grade black walnut with a natural grain finish, and the headband is carbon fibre. Total weight is 425 grams, which for a 101mm planar puts it in familiar territory for the category — planar drivers of that diameter carry substantial magnet assemblies, and the carbon-fibre headband is presumably where FiiO has tried to claw some of that back.

The supplied cable is 6N monocrystalline copper, cryogenically treated, terminated in 4.4mm balanced. Those are material and process descriptions; no source offers a demonstrated performance effect for either, so we will not assign one.

What's in the box

Major HiFi lists the following accessories:

• 6N monocrystalline copper balanced cable with 4.4mm termination
• 6.35mm adapter
• 4-pin XLR adapter
• Two sets of earpads
• Storage case

The dual earpad sets are a notable inclusion at this price, since pad material is one of the few variables an owner can change that meaningfully alters an open-back headphone's presentation. What the two sets are made from, and how they differ, is not specified in the sources.

Price and availability

The FT15 is $499 in the United States. eCoustics lists that figure and notes an Amazon listing at the same price; Major HiFi gives $499.99, which is almost certainly the same MSRP reported with and without rounding. No UK or European pricing has been published.

The headphone is on sale now through FiiO and authorised dealers, with international availability rolling out in stages. eCoustics describes that staged international rollout; Major HiFi notes availability via FiiO's own site and through Audio46, without giving a ship date. Neither source provides a single global on-sale date, so there isn't one to report.

Reading the announcement

What FiiO has published is a specification sheet and a set of design claims, and that is genuinely all that exists at this point. The measurable, uncontroversial facts are the ones worth holding onto: a larger driver, a substantially thinner diaphragm with a diamond coating, a 24-ohm load, 95dB/mW, 425 grams, walnut and carbon fibre, and a $499 asking price with a reasonably complete accessory bundle.

Everything in the territory of how the FT15 actually sounds — whether the extra radiating area translates to anything audible, whether the thinner diaphragm behaves as intended at volume, how it compares with the FT5 it succeeds — remains open. Planar magnetic headphones are particularly resistant to prediction from specifications, because driver size and diaphragm mass interact with the magnet geometry, the acoustic chamber and the pads in ways a spec sheet does not capture. Independent measurements and listening reports will follow; until they do, the sensible reading of the FT15 launch is as an engineering description rather than a performance one.

Frequently asked questions

What is the FiiO FT15 and what does it replace?

The FiiO FT15 is an open-back planar magnetic headphone announced on 17 September 2026 as the successor to FiiO's FT5. Coverage from eCoustics, Major HiFi and Darko.Audio all frame it as replacing the FT5 in FiiO's range, though none of those sources states that FiiO has discontinued the FT5.

How big is the FiiO FT15's planar driver?

The FiiO FT15 uses a 101mm planar magnetic driver, up from the 90mm driver in the FT5. Major HiFi gives the effective radiating area as 6,443.5mm², and eCoustics describes the change as roughly 35 percent more active diaphragm area. The 101mm figure is a diameter, not an area measurement.

How thin is the FiiO FT15's diaphragm compared with the FT5's?

The FiiO FT15's diaphragm measures 800 nanometres thick with a full-face diamond coating. The FT5 used a 6-micron film, equivalent to 6,000 nanometres, making the FT15's diaphragm 86.7 percent thinner — a figure FiiO states directly and one that checks out arithmetically.

What impedance and sensitivity is the FiiO FT15 rated at?

The FiiO FT15 is rated at 24 ohms impedance and 95dB/mW sensitivity. eCoustics reports it is easier to drive than the FT5 and workable from portable players rather than requiring a dedicated desktop amplifier, though that claim comes from FiiO and eCoustics and has not been independently bench tested.

What is included in the box with the FiiO FT15?

According to Major HiFi, the FiiO FT15 ships with a 6N monocrystalline copper balanced cable terminated in 4.4mm, a 6.35mm adapter, a 4-pin XLR adapter, two sets of earpads and a storage case. The cable is described as cryogenically treated.

This article was written by an AI system from Into The HiFi AI Desk, generated from the following sources, with no human editing pass before publication: eCoustics — FiiO FT15 Open-Back Headphones Arrive With 101mm Planar Driver, Major HiFi — FiiO FT15 Planar Headphones Launch With 101mm Drivers and Walnut Earcups, Darko.Audio — FiiO's FT15 open-back planar headphones replace the FT5, likehifi.de — FiiO FT15: Flaggschiff-Kopfhörer mit Planartreibern und Walnussschalen.