Fostex TH909 headphones

I’ve been aware of the name Fostex probably close to as long as I’ve been interested in high fidelity sound. And that has been a long time. But I think the Fostex TH909 is the first time I’ve actually used any Fostex gear. And it turned out to be a great introduction.


  • Over ear, open back headphones
  • 50mm dynamic driver using magnetic repulsion system employing neodymium magnet and a DIODYNA diaphragm
  • Lacquered Japanese Cherry Birch housing
  • Thick 7N-OFC cables to enhance bass reproduction
  • 2 metre cable terminated with rhodium-plated two-pin connectors at headphones end, and 6.35mm gold-plated plug with duralumin casing
  • 25 ohms impedance
  • 100dB/mW sensitivity
  • 1,800mW maximum input
  • 5-45,000 hertz frequency response
  • Provided with leather texture pouch and headphone stand
  • Summary: Fantastic looking headphones with excellent reproduction, marked by particularly impressive bass. Suitable for use with pretty much any gear, even low output equipment.
  • Price: $2,499
  • Available at fine high fidelity retail outlets, and direct from distributor's retail division here, or here if you’d like a different colour.
Fostex TH909 headphones

Notes on the Fostex TH909 headphones

These truly are premium model headphones. They come in two versions: the standard model reviewed here and the limited edition Sapphire Blue edition, available here. The standard model looks glorious. Really. It’s finished in a lustrous deep red made of multiple coats of lacquer that still admits a hint of the underlying wood grain of the Japanese Cherry Birch structure.

They are apparently based on the highly-regarded Fostex TH900mk2 headphones, which are closed-back models. Those ones have the advantage of even more of that gorgeous red lacquer finish. Of course, the present headphones were tweaked and tuned to work optimally with an open-back housing.

I find it interesting that these headphones use dynamic drivers, while several of the companies markedly lower-cost models are planar magnetic. The casual hifi enthusiast will generally say that planar magnetic is a better technology for headphones. Clearly Fostex disagrees.

Fostex TH909 headphones

They use two-pin connections between cable and headphone earcups, similar to those used by Sennheiser. Since they are removable they can be replaced in case of breakage, or switched to balanced via 4-pin XLR if you want to try that out. The amplifier end is terminated in a particularly stylish 6.35mm jack. No 6.35mm to 3.5mm adaptor is included.

One cool feature – perhaps this should be provided with all premium headphones: a simple plastic, but space-saving and effective, headphone stand is included.

The construction of the headphones is sturdy and the finish immaculate.

Listening with the Fostex TH909 headphones

The first headphone amplifier I used with the Fostex TH909 headphones was the one built into the Bryston B1353 integrated amplifier. I thought that its moderately high output impedance may have been combining with a higher impedance in the bass of the Fostex headphones to really pump up the headphone’s bass. Pump it up in a rather attractive and exciting way, to be clear.

But, as we’ll see, although there is a slight impedance rise in the deep bass for these headphones (at around 30 hertz), it’s only a mild one and with the Bryston the effect could only have been a few tenths of a decibel. So clearly, that powerful bass is inherent in these headphones. Who said that open backed headphones had a tendency to bass deficiency?

Fostex TH909 headphones

Let me describe the overall sound, though. It’s precise and detailed and extremely well balanced. Yes, I know I am suggesting that the bass is up fairly high, but it’s so tight and it’s the mostly the lower bass below, oh, I’d say 60 hertz, that’s up a bit higher.  Down there, there is quite a wide leeway in raising the level before it starts to overwhelm or otherwise hurt the higher octaves.

As I’ve been typing, I’ve had the self-titled debut album by Dire Straits playing. This version is a remaster (I think) on DSD for sure. I’ve switched over to the iFi ZEN CAN headphone amplifier for a guaranteed low impedance output (0.55 ohms). The level control of the ZEN CAN is at around 10 o’clock with the four-position gain switch at its lowest level. Yet the overall sound level is high. These headphones are really quite efficient. I’ll return to using them with a low output source, but I can already say that their output levels will be fine even for those. (Even, probably, for Euro-hobbled devices.)

The album has reached the track “In the Gallery”. The bass guitar is delivering its rhythmic drive with the expected power, while the cymbals click and tinkle clearly, the crash with restraint due to the mix. Knopfler’s picking in the left channel is precise and clear, and his dynamic control on full display. His … interesting? … voice is being delivered with restraint as well. He can come across as kind of scratchy with some gear, but not here. Instead he’s smooth.

The drum kit seems to be without any level of dynamic restriction. I could listen to this all day.

Fostex TH909 headphones

Indeed, I have spent several all days listening with these headphones.

Let’s switch genre. For understandable reasons listeners – and hifi reviewers – keep returning to Miles Davis’ 1958 masterpiece Kind of Blue. On one level it seems silly. Why would you listen to something recorded with 1950s technology – Dolby noise reduction hadn’t even been invented then – onto tape which had at best a signal to noise ratio of maybe 70dB? Over the last couple of days, I’ve twice listened straight through the original soundtrack of West Side Story, which would have been recorded only two or three years later. A particular favourite is the debut album of Nina Simone, Little Girl Blue, also released in 1958.

Well, there’s something offsetting the undoubted higher distortion and noise levels in these recordings: an absence of processing. In particular, an absence of dynamic range compression. They didn’t have decent tools for doing that in those days, so they just didn’t do it at all. That carried through to some material from the late 1960s, like recordings by Blood, Sweat and Tears, and Janis Joplin and Big Brother and the Holding Company.

Fostex TH909 headphones

If I recall correctly, Kind of Blue was recorded on three track so the stereo delivery isn’t fake. And playing back “So What” (the DSD version) through the Fostex TH909 headphones there’s a lovely intimacy in the recording. The walking bass was beautifully articulate and dead even in level as it runs through an octave or two. The drums, which are played mostly in a controlled way so that they don’t dominate, nonetheless remained dynamically powerful within that constrained level, with the headphones revealing the texture of every strike, no matter how rapid or subtle. And every so often a strike or two would be lifted through the mix, generating in me a genuine sense of excitement.

The Telarc version of Bach’s Passacaglia and Fugue in C minor, rendered on a mighty pipe organ capable of delivering the bottom pedal C at 16 hertz, killed. With these headphones it was as close to the experience I have had with my (now gone) 15-inch, 400-watt, sealed-enclosure subwoofer. Even as the climax is approached and the organ steps up by several decibels, the headphones held together the rich complex harmonics of a full range of pipes letting loose as well as any gear I’ve used. They weren’t entirely successful, but I think the remaining confusion is embedded in the recording.

Fostex TH909 headphones

Another genre switch. “Killing in the Name” from Rage Against the Machine’s 1992 self-titled debut is a fine piece for checking whether loudspeakers – or headphones – can keep everything it time and, most importantly, reveal the space within a piece of music. For that they need to put on the brakes instantly when the signal demands it. These headphones responded perfectly, all the while bringing to the surface a rumbling underpinning of which I’d been previously unaware.

Finally, a platform switch was called for while retaining the same track: “Killing in the Name”. This time I streamed it from TIDAL with an iPhone 8 and an Apple Lightning headphone dongle – $15 at the Apple store. A pretty good performance. Decent control, although there was some sibilance on the voice which hadn’t been there when I played it using the iFi ZEN CAN. But, then, I couldn’t even say for sure that the streaming TIDAL version is the same as the version I have on my NAS. Regardless of that, even using an iPhone and analogue adaptor – about the most basic audio rig you can imagine – the Fostex TH909 headphones delivered a powerful, exciting performance with the volume level set between 7/10 and 8/10, and a very loud playback performance. There was plenty of gain available for even louder playback.

One last word about an extremely important matter: I found them super comfortable to wear for many, many hours at a time. The only slight exception was overheating a little in a warm room. That is, my ears were overheating, not the headphones.


I ran my usual test, measuring the frequency response of the signal presented to these headphones when a 466-ohm resistance is inline. This replicates the situation with many home theatre receiver headphone outputs, and even some stereo amplifier ones. Here’s what that looked like:

Fostex TH909 headphones -- frequency input levels with 466 ohms inline

The green line is the most important, since that was when the headphones were over a very fake head (it’s just a cardboard box). As you can see, the output varied by around 2.5dB, most obviously shown in the bass boost. That’s pretty much worst case, and a couple of decibels of bass boost, centred on 30 hertz, is really no bad thing. With more normal gear, which typically sport an output impedance of less than 10 ohms, that variation becomes insignificant.


If you like your bass, but also want extremely accurate and music headphones, you really ought to check out the Fostex TH909 headphones. I for one love them.

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