FiiO FD3 Review

FiiO FD3 review featured

In this review, I’m looking at the FiiO FD3 earphone. The FiiO FD3 is the latest IEM model in the brand’s FD lineup. It’s equipped with a 12mm diamond-like carbon (DLC) dynamic driver and retails at $99 for the regular version and $139 for the FD3 Pro.

Disclaimer: This sample was provided by FiiO for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.

  • Ergonomics and fit
  • Included accessories
  • 2 sets of tuning nozzles
  • Balanced, detailed sound
  • Soundstage quality
  • Tonality may be too bright for some

FiiO FD3

  • Driver: 12mm DLC Diaphragm Dynamic Driver
  • Frequency response: 10~40kHz
  • Sensitivity: 111 dB/mW (@1KHz)
  • Impedance: 32Ω (@1KHz)
  • Weight (per earbud): About 7g

Packaging & Accessories

Box front

The FD3 has some really nice packaging for a $100 IEM. It comes in a black box covered with holographic line illustrations that change colours under the light. Not only is the box impressive though: the contents bundled within are also above the standard. Here’s what you get inside:

  • FiiO FD3 IEM
  • Detachable MMCX cable
  • High-quality plastic storage case
  • 3x pairs of ‘bass’ silicone eartips
  • 3x pairs of ‘vocal’ silicone eartips
  • 4x pairs of ‘balanced’ eartips (2x foam + 2x silicone)
  • 2x sets of tuning nozzles
  • MMCX removal tool
  • Cleaning brush
  • Quick start guide
What's in the box


FiiO FD3 shell design

FiiO is bolder than most IEM manufacturers when it comes to physical design. They don’t rigidly adhere to the same form factor over and over again but change things up consistently. Even models from the same line can look radically different: for example, the FD3 looks nothing like FiiO’s FD5.

In the case of the FiiO FD3, it has a disc-shaped body that’s made from a highly polished aluminium-magnesium alloy. On the top of the disc is a cylindrical tube incorporating FiiO’s patented balanced air pressure design. This not only produces a more natural sound but also protects your hearing by putting less air pressure on your eardrums.

FD3’s faceplates contain a celluloid panel covered in 2.5D glass. The celluloid is a marbled grey colour that contrasts nicely with the gold FiiO logo and surrounding gold band. The craftsmanship is exquisite and once again we see FiiO leading the pack when it comes to build quality.

FD3 shell with filter nozzle

Apart from the semi-open design, resulting from the balanced air pressure design, there’s another small vent near the base of the nozzle. The FD3 nozzles are also tuning filters (which FiiO calls sound tubes) and there are 2 sets included in the package, one red and one black. The red tubes are called ‘balanced’ and the black ones ‘treble resolution’. I’ll talk more about those in the sound section below.

Internally, FD3 hosts a large 12mm Diamond-Like Carbon (DLC) diaphragm. DLC drivers are light and very rigid, giving them faster transients and lower distortion. In addition, FD3 inherits the same flagship-grade acoustic prism found in the FD5. The acoustic prism enhances sound wave diffusion and reduces the time delay caused by sound wave propagation.

Although FD3 looks a little awkward in terms of shape, it’s actually a very comfortable IEM. The shells contour snugly to my ears and I didn’t experience any pressure or hot spots during testing, even during long listening sessions.


FiiO FD3 stock cable

FD3 comes with a 4-strands high-purity monocrystalline copper cable. It’s a twisted cable and relatively thick, making it feel strong and durable. The MMCX connectors are transparent plastic while the Y-split, chin slider and L-shaped plug are aluminium.

While the quality of this cable is unquestionable, it’s not the best in terms of handling. It suffers a little from microphonics (cable noise) and is a bit bouncy. I think an IEM as pretty as the FD3 could have a nicer cable but I guess that’s why there’s a Pro version with FiiO’s modular cable included.


Gear used for testing includes:

FiiO FD3 frequency response red filter
FiiO FD3 (red filter) frequency response.

The FiiO FD3 has a balanced sound signature with a light to moderate bass boost, forward midrange and detailed but smooth treble. The overall clarity is very good without resorting to excessive brightness or compromised timbre. In fact, FD3 has one of the most natural tonalities I’ve heard at this price point.

FD3 is an efficient IEM and doesn’t require much power to perform. I found that using dongle DACs and low-powered DAPs like the FiiO M6 were adequate to make FD3 sing, however, it does have some ability to scale with a better source.

FiiO FD3 red filter vs black filter.

By default, the red filters are attached when you take FD3 from the box. The red filter is fairly balanced and gives a warmer presentation. In comparison, the black filter improves overall clarity, detail retrieval and soundstage dimensions. This is a result of a small boost in the upper midrange and treble.

I enjoy the red filter but switching to the black really opens up the sound, giving it more clarity, better dynamics and a larger soundstage. However, for longer, more relaxed listening sessions, I sometimes found myself switching back to the reds. For anyone who’s treble shy, the red filter will suit you better but for those who like more zing and zest in their sound, the black filter will give you just that.


FD3’s 12mm DLC driver delivers a high-quality and engaging bass. It’s not a huge bass in terms of quantity, so bassheads might feel the need to look elsewhere. But for anyone else, the FD3 will treat you to some great low frequencies.

That’s not to say the FD3 can’t deliver a meaty low end though. On the contrary, listen to Sundial Aeon’s “Elemental” and the kick drums hit with intensity and thump. You get the sense of a big bass but the best part is the way it’s intertwined with the mids and highs. There’s no bass dominance or smothering of the midrange, yet it’s powerful enough to give you thrills and rhythmic drive.


Vocal lovers will appreciate FD3’s midrange forwardness. Male and female vocals are upfront and intimate. They’re not cloying or syrupy though, they have good detail and clarity. Furthermore, the overall clarity of the midrange is excellent, even more so with the black nozzle filters.

Instruments are handled with confidence too. The texture of the electric guitar strings in Tacoma Narrows Bridge Disaster’s “Orogenic” is exquisite. Yet FD3 never sounds harsh or shouty. Grungy electric guitars, high piano notes and belting female vocals are all handled with aplomb


Not to be outdone by the bass and midrange, FD3’s treble steps up with style. It’s a treble that provides good detail retrieval, energy and openness. It’s also relatively forward in the overall tonal balance but still doesn’t come across as sharp or brittle. In fact, FD3 has one of the best treble timbres you’ll hear in this price bracket.

This is enhanced even further by the black filters which lift it even more. The treble extension is good, as is the note density and definition. It’s a lively treble that can exhibit sparkle and air without giving you listener fatigue.


As you’d expect for a semi-open IEM, the FD3 has a large soundstage. But what makes this stage special is the solidity of instruments and vocals and its roughly equal dimensions in both width and depth. There’s a good sense of height here too, something most entry-level earphones struggle to create. Imaging is precise and there’s good spacing between instruments.

FiiO FD3 shell and celluloid faceplate


Moondrop Aria ($79)
FDS vs Aria
FiiO FD3 (red) vs Moondrop Aria (grey).

The Moondrop Aria is another excellent entry-level single dynamic driver IEM. You can see the similarities in the frequency curve with the FD3 above. Aria has less weight in the lower frequencies giving it a natural spaciousness. It doesn’t have as much bass impact as the FD3 but both IEMs have good bass quality.

There’s less thickness in Aria’s lower midrange too, giving it a leaner more ethereal quality. FD3 is bolder and more upfront. Aria has less lower treble energy, giving it a softer sound with slightly less micro-detail retrieval. In comparison, FD3’s forward lower treble gives it a brighter tonality. Both IEMs have good imaging and soundstage dimensions but FD3 has greater depth to its stage.

FiiO FH3 ($129)
Fd3 vs FH3
FiiO FD3 (red) vs FiiO FH3 (grey).

The FiiO FH3 is a hybrid triple-driver IEM with a 1DD+2BA config. FH3 has greater sub-bass extension and cleaner leading edges. FH3 has a more physical and authoritative sub-bass rumble.

Although FH3’s midrange is more forward, it stays clean thanks to the fast transients of the balanced armature driver. It gives the FH3 a slightly less dynamic overall tonality but with slightly better resolution and instrument separation.

FH3’s perceived treble is less as a result of its upfront midrange. Despite this, FH3’s detail retrieval is equal to or a tad better than FD3. Where FD3’s treble shines in comparison is its natural timbre. FH3’s soundstage is narrower, giving the FD3 a little more space between instruments and a slight advantage when it comes to imaging.

FiiO FD3 with cable


The FiiO FD3 is another great addition to the brand’s lineup. It comes with a generous, practical bundle of accessories plus a premium build quality and aesthetic. When it comes to audio quality, the FD3 can compete with pretty much anything else in its price range. It has a dynamic sound with a healthy dose of smooth but vigorous treble energy, punchy bass and good overall timbre.

Stay in the Loop with the Latest News and Updates!

We don’t spam! Read our privacy policy for more info.

Founder of Prime Audio
Notify of

1 Comment
Oldest Most Voted
Inline Feedbacks
View all comments

Subscribe to Our Newsletter

Stay in the Loop with the Latest News and Updates!

We don’t spam! Read our privacy policy for more info.