Fostex TH616

Annniversary edition of the open hi-fi over-ear model

In a nutshell

The Fostex TH616 open-back over-ear model are high-end headphones for hi-fi enjoyment. Buyers can expect detailed highs, high wearing comfort, an elegant appearance and a favourable price-performance ratio. However, you will have to make compromises in terms of sonic warmth and stereo width.

  • Transparent, detailed sound
  • Clear transient imaging
  • Premium materials and manufacturing
  • High wearing comfort
  • Lower mids underrepresented
  • Loose fit
  • Narrow stereo width

The Fostex TH616 are open over-ear headphones with an elegant design and detailed sound, here released as a hi-fi anniversary model.

Fostex are releasing the open TH616 over-ear headphones as an anniversary edition aimed at hi-fi enthusiasts. We take a look at what they have to offer and where they stand in comparison to other Fostex models.

Fostex TH616 package

The detachable straight cable included with the TH616 is 3 metres long. With its gold-plated 6.35mm stereo jack plug, it is well protected against corrosion. The strands of the unbalanced, fabric-covered supply cable are made of pure copper. However, the cable can also be replaced with an optional 4-pin XLR cable with balanced signal routing, which is also 3 metres long. The TH616’s connections are plated with platinum rhodium. This prevents tarnishing and ensures that the sockets make good contact. This means that we are dealing with a product of consistent quality.

Also included, an unpadded transport bag made of imitation leather with a drawstring closure. A final word about this package, an instruction manual is included, but it is only available in Japanese.


Material and construction of the Fostex TH616

I’m not an expert on East Asian products myself, but if you know your way around, you’ll notice that the elegant design of the earcups follows the guidelines of classic Japanese aesthetics. Following on from the closed Fostex TH610, the TH616 also comes with ear cups that are milled from black walnut wood. The important difference here is that the backs are open rather than closed. The high rigidity of the wood is intended to help prevent the shells from resonating. Despite their low weight, the duraluminium housings are responsible for stability. This material is an alloy of aluminium, copper and magnesium, which is said to have a hardness similar to steel.

The imitation leather ear pads are designed not only to be comfortable but also to reduce reflections inside the earcup. There is nothing left to be desired when it comes to workmanship. Anyone looking for high-quality will not be disappointed with these headphones.


Technical values of the Fostex TH616

The interior of the Fostex TH616 features 50mm drivers with Fostex’s own Biodyna cones, as used in the high-end model TH909. They consist of a wafer-thin mixture of materials, including bio-cellulose fibres. Neodymium magnets ensure a 1 Tesla strong magnetic flux density. This should enable a particularly detailed, differentiated and dynamic reproduction with very low distortion. Despite high-end aspirations, their impedance of 25 ohms makes them an excellent match for smartphones, tablets and laptops. However, a suitable 3.5mm adapter is not included.

Their sensitivity of 96 dB was not very high, so buyers should not expect record-breaking volumes, but having said that the frequency response was all the more impressive. It corresponded to that of the TH610 and ranged from an ultra-low 5 Hz up to 45 kHz. The TH616 therefore offered significantly more sound information in both the bass and treble ranges than typically processed by the human ear.

Handling of the Fostex TH616

The plugs on the supplied cable are inserted into the earcups at both sides. When inserting them, a clicking sound made it clear that the two-pin CIEM plugs have a retention fuse. An equally audible click lets the TH616 memorise the last size setting of its headband. When you put them on, the weight of just 370g without cable makes these headphones feel really light for their size. What’s more, the TH616’s soft imitation leather ear pads were very comfortable to wear. Due to the low weight of the device, it doesn’t matter that at first glance the headband padding seems undersized as, in practice, this does not detract from the wearing comfort.

The ear cups can be rotated and swivelled. This can only be done to a small extent, but it adequately allows you to achieve a good fit. Nothing stands in the way of long listening sessions with the TH616. This is because of the low contact pressure of the headband. However, you should avoid rapid head movements if you don’t want to accidentally shake the headphones off.

Sound of the Fostex TH616

The Fostex TH616 impressed us with transparent sound. And by that I mean a really overly transparent sound. The sonic resolution of these headphones was extremely rich in detail, especially in the treble range. There was also sonic openness in the super-high frequency range.

At the other end of the frequency spectrum, this model delivered restrained but round bass that extended into the low bass range.

However, to my personal taste, the TH616 lacked warm mids, even if the presence and intelligibility of voices and vocals were excellent during playback, the lower mid-range was distinctly underrepresented in the sound image. Guitar music, in which the upper mids were strongly represented, quickly became a strain on the ears. But, of course, this is a subjective assessment. There will certainly be one or two people who are looking for exactly this sound or who are prepared to get used to this sound signature over a longer period of time. If this is the case, then the TH616 allow you to enjoy precisely mapped transients.

And surprisingly, even though the stereo stage did not feel particularly wide, at least for my hearing, the special, treble-heavy sound image of these headphones made them particularly suitable for listening to classical music. I found a great advantage in the fact that the acoustic isolation to the outside and the damping of external noise were marvellously low with these open headphones. This favoured their sound image.


The Fostex TH616 are the open version of the closed TH610, and the Japanese manufacturer has produced limited quantities of this model to mark the 50th anniversary of the company. The similarities with the closed version include not only the technical values but also aspects of the design, the high-quality choice of materials, the high quality of the production and the way the cable is routed on both sides.

These headphones offer perfect wearing comfort. And dynamically, they score points with their transient reproduction. However, taken as a whole, the sound profile was a matter of taste. This was because the treble and upper mids were most strongly represented. Bass was also present at some distance. Unfortunately, the lower mids, which are responsible for tonal warmth, were not very pronounced. Neither was I quite convinced by the width of their stereo.

Nevertheless, if you’re into classical music and are looking for a comparatively affordable alternative to the open high-end Fostex TH909, you should definitely give the Fostex TH616 a listen.

6 months ago by Carsten Kaiser
  • Rating: 4.13
  • Sound
  • Handling
  • Price/Quality
  • Function

Technical specifications

  • Ear couplingOver-ear
  • Typeopen
  • Transducer principledynamic
  • Frequency response (headphones)5 - 45.000 Hz
  • Impedance25 ohms
  • Sound pressure level (SPL)@1kHz, 1mW: 96 dB
  • Weight without cable370 g
  • Cable length300 cm

What's in the box

  • 6.35 mm jack cable, unbalanced
  • Travel pouch

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