FiiO FH9

Wired in-ear monitor for discerning music listeners

In a nutshell

For a price of 599 euros, you get a sumptuously designed, superbly crafted, exemplarily equipped pair of in-ear headphones with the FiiO FH9. The hybrid design draws on the strength of the full range and delivers a convincingly balanced performance in terms of sound at an attractive price. The bass emphasis and somewhat sober sound, on the other hand, are a matter of taste.

  • convincing workmanship
  • supplied adapters for balanced operation
  • high-quality connection cable
  • tuning via audio filters
  • lots of adaptors

The immaculately crafted FiiO FH9, designed as an advanced hybrid device, is an in-ear monitor for sophisticated demands. In addition to first-class specification with silver connection cable and symmetrical connections, these headphones offer a sound tuning that places itself well above off-the-shelf products but does not quite reach the expensive reference class.

FiiO Electronics Technology Inc. Co. from the People’s Republic of China has largely specialised in the field of headphones, headphone amplifiers and converters (to the reviews). For some time, the FiiO FH9 has occupied the top position among the manufacturer’s headphones alongside the limited FDX.

The high-quality finish of this universal fit product uses a titanium housing and makes a sophisticated and robust impression – earning our admiration straight away. Technically, it is a hybrid system that uses a dynamic 13.6 mm driver with a “DLC” cone for the bass range and no less than six Knowles balanced-armature drivers per side, each with tuned sound tubes, for the mid-high range. The cabinet, where the faceplate has been partially made air-permeable with a grille to allow freer movement of the dynamic driver and thus a potentially more natural and fatigue-free sound result, is a very interesting feature.

The connection technology is a highlight: the FH9 comes with a decorative, braided balanced cable made of silver wire, which would certainly have a handsome price tag as an accessory on its own. Thanks to the MMCX connector, it can be replaced at any time. The gold-plated 3.5mm connector is exchangeable and can be replaced with the enclosed balanced four-pin connectors in 2.5mm and 4.4mm (Pentaconn) format using a screw connection. The competition could take a leaf out of FiiO’s book here!


The package is supplemented with a smart folding case made of imitation leather (HB5), 16 pairs of adaptors in different shapes and materials, as well as exchangeable “audio filters”. This is a special design feature: the sound outlet of the FH9 has a screwed end piece with an integrated filter unit. There is a choice of three end pieces (balanced, bass, treble), with which the sound image can be further adapted to one’s own taste.


The FiiO FH9’s no-frills, high-quality design is fully focused on music enjoyment. There are no extras like an integrated microphone. Although the FH9 is not explicitly ergonomically shaped, in my case, it fitted comfortably and low enough in the ear, even over long listening sessions, despite its increased weight. The cable is routed over the back of the ear, which makes it a little awkward to put on, but it does offer improved and more stable positioning. Thanks to the abundant selection of fitting pieces, it should be possible to find the right seal. Finally, there was no need to worry about the level of reserves on offer.



The FiiO FH9 was tested with a Shanling DAP M3X, an iPhone 8 with adapter, a Macbook Pro and a Dragonfly Red. Neutral audio filters were used. In my case, the external isolation was quite good, allowing you to listen to the music in a focused manner. At the same time, the semi-open construction does not disturb the person sitting next to you. Another positive aspect is that these headphones produce full, rich sound even at low levels.

The sound performance is consistent and quite appealing, something that was to be expected given the price. The FH9 does very little wrong except for a slight bass emphasis. It delivers a coherent, natural sound with high detail resolution. However, I would not describe the FH9 as objective reference headphones for sound engineering work but rather as a solution for a music connoisseur with high demands. A certain sobriety is noticeable, which makes the design a matter of taste. Apart from listening to music, I could also imagine that the FH9 would find fans as an in-ear monitor in the professional sector – an area that FiiO does not address as a target market.

In the bass, the design is powerful and punchy but matter-of-fact rather than warm. Low bass, contour, dynamics, tonality and demarcations between several sound layers are well reproduced, but at the same time, there is also the aforementioned slight overemphasis in this area. For example, these headphones excellently master club sound. The Infinite Disco version of Kylie Minogue’s “Light Years” was wonderfully powerful, and the lush reverberation was immediately noticeable on the album’s follow-up song “Slow”.

In the midrange, the FH9 delivered a detailed performance. Voices like Gloria Estefan (“Mi Tierra”) or Roy Orbison (“The Comedians”) reach the ear with numerous subtleties but a slight emphasis in the high-mids. Classical and acoustic instruments have a natural character, so I would have no qualms about using the FH9 for classical music as well.

Finally, these headphones also succeeded with dense rock and metal mixes. The force and dynamics of Candlemass’ doom masterpiece “Astorolus” were reproduced to my listening pleasure, as was the complexly intricate “Bleed” by Meshuggah, something that can all too often sound tinny. The mix of “Can’t Stand Still” (AC/DC) pushed just like it should, while Slayer’s mid-range “Repentless” lacked some bite.

In the high-frequency range, the FH9 succeed with a lively response providing appealing detail and transient resolution. I didn’t notice any annoying harshness, but neither did I notice the airiness of a reference class pair of headphones, as you might experience with a pair of open headphones like the Sennheiser HD 800 S.

The stereo panorama was fine and broadly resolved. This was where the BA drivers showed their strengths and allowed for an intense immersion in the mix. However, the result was not quite as spectacular as with the U6t by 64 Audio, but this may be due to the powerful bass. After all, the soundstage of good recordings like Bob Dylan’s “Man in the Long Black Coat” is built up comprehensibly.

Competitors, such as the iBasso IT07, with a similarly elaborate driver line-up, are more expensive. For a direct comparison, as mentioned above, I used the 64 Audio’s BA-only U6t design, which also turned out to be significantly more expensive.

1 year ago by Ulf Kaiser
  • Rating: 4.25
  • Sound
  • Handling
  • Price/Quality
  • Function

Technical specifications

  • Ear couplingIn-ear
  • Typesemi-open
  • Transducer principledynamic + Balanced Armature
  • Frequency response (headphones)10 - 40.000 Hz
  • Impedance@1kHz: 18 ohms
  • Sound pressure level (SPL)1kHz @ 1mW: 108 dB
  • Weight without cable12,8 g
  • Cable length120 cm

What's in the box

  • FiiO HB5 case
  • detachable cable, monocrystalline silver
  • 3 pairs of audio filters: balanced, bass, treble
  • 3 plugs: 2.5, 3.5 and 4.4mm
  • 3 pairs of bass ear tips (S/M/L)
  • 3 pairs of balanced ear tips (S/M/L)
  • 3 pairs of vocal eartips (S/M/L)
  • 2 pairs of form tips (M)
  • 2 pairs of double flange tips (M)
  • SpinFit CP145 (S/M/L)
  • cable clip
  • cleaning brush
  • MMCX Tool

Special features

  • available in black or titanium

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