Fostex is a Japanese company pro audio company founded in 1973. It is famous in audiophile circles with 2 series of headphones: the probably longest continually produced planar dynamic headphones Tx0RP and interesting “bio-dyna” based dynamic headphones THxxx.
6 Likes
I have the Fostex T50RP MK3 and the Fostex T60RP. I find that the Fostex T50RP MK3 is the better of the two. I don’t know what justification Fostex has for the higher price of the Fostex T60RP other than for the wood cups just for looks.
2 Likes
As I understand, driver is the same for all 4 models, difference is only wood cups for the 60 and different (or no) venting on the 20/40/50. Not sure about the popularity of the 50 model over others? As per Innerfidelity measurements, 40 model seems to have the most balanced FR. Also it’s the closed back model. Seems like a good entry level closed back. (Not sure about the isolation, though…)
1 Like
I have been slowly modding a pair of 50’s for about 6 months now, when I finally get them to the point that I like them, I will post what I did here. Should only be a few more weeks now. Lots of clay, tape, pads, felt, glue and cotton.
2 Likes
Not directly a Fostex headphone, but I bought Creative Aurvana Live! 2, which is based on Foster biodyna driver. Bass impact is really special. Headphone is light and comfortable. Tuning is not exactly audiophile, more something along the V-Moda line. When EQd, it gains clarity and spaciousnes. Unfortunately, because of the cable connection issue, I have returned them to the store. Pity about the QC… But it made me interested in biodyna phones in the future.
2 Likes
Well as I returned CAL!2 I bought T40RPmk3. However, in the mean time store managed to fix CAL!2 so in the end I retained both headphones. I’m starting to hoard them, again. 
So, T40RP. Wow! Build is sturdy, design is functional. I like them. 3.5mm jack on HP is nice and practical. I also like the lock mechanism. HP is medium weight at 315g, but it’s ok. The clamp is medium but the pads are thin so comfort is not the greatest, but it is wearable. Pads are pleather so you will be sweating, especially in summer. The sound. This is my first planar. If I could put it in one word it would be smooth. Like it’s missing the kind of grainy background that I notice on the dynamic HPs. Second thing is bass. And the bass is really big, strong and maybe a little boomy but without overwhelming mids much. The tuning is fantastic with 80Hz till 5kHz almost strictly on target with rolled off sub bass and attenuated treble but that is almost wholly fixable with EQ. They also sound great without any EQ. Isolation is solid. They are the best closed headphones I have yet heard. At the price I really don’t think anything comes close in the category. I’m really surprised I didn’t see them recommended more, for people needing great reasonable priced closed backs. Only caveat I could give is comfort, but I guess that is somewhat fixable with pad swap, if you are ready for some sound trade offs.
3 Likes
Another thing to keep in mind with these headphones, is that with thicker pads you will need more power to drive these.
I talk about my T50RP mk3 mods here (Same driver):
I will also be converting these to a close back in the following weeks/month. I will post an update when I get it finalized. Overall these are a great pair of headphones, I personally consider them very mediocre stock, but they have the potential to be absolutely amazing.
2 Likes
Also, one common misconception. I have often found advices that these “need nuclear powerplant to drive”. I guess that probably sprung from the specification that they can take up to 3 Watts of power. However, I found them relatively easy to drive. I took them for a walk playing them from my phone and found it a very enjoyable experience. 
If I recall correctly, the Fostex T50RP MK3 are the least efficient headphones I have ever used. I have a collection of over 50 headphones.
2 Likes
The only HP I have that I can say is challenging to drive with casual sources (like a phone) is DT770 250 Ohm.
Let me clear this up a little, with these headphones. Yes, you can move the driver on the TX0rp series with almost anything. BUT, there is a HUGE difference in sound quality when you give then more power. I have even noticed an improvement in sound when jumping from 5W to 10W. So, that is why people say these are really hard to drive headphones, it is nearly impossible to give them enough power to reach their full potential.
Well, sure. It’s just that casually reading I was under impression that it would be more difficult to drive (as with my dt770). I’m glad that it isn’t so. It really is a wonderful headphone.
Service did contact me later that they fixed my CAL! 2, so in the end I decide to keep them too. It’s a nice looking, solidly build, surprisingly comfortable and lightweight headphone. Pleather pads are comfortable, but not breathable. You will sweat, if wearing outside. It comes with detachable cable with microphone, stop/start button and analog volume slider. Nice. The sound. Bass impact is best in class. However, tuning on this model is far from balanced. Think something along the V-Moda M-100 line. Fun, but overwhelming bassy sound. While it can get fatiguing for music in general, for EDM / modern pop the bass performance is fantastic. Really, no other models I heard come near it. It is a big, physical, club-like experience. Higher frequencies are recessed, grainy and somewhat grungy.
When EQ’d it became a solid headphone. Somewhat dark tilt remains, however. Mids stay somewhat recessed. Soundstage gets wider and is solid for a closed back. Solid sound, maybe missing detail a little because of the dark tonal bent. Higher frequencies stay coarse.
It is a specialist headphone, but for its narrow subset it really is incomparable.
1 Like
Recentely bought a second hand TH900 and with EQ this headphone has surprised me A LOT.
The technical capabilities are outstanding.
It really does scale massively with better dac/amps compared to some other high end headphones I have.
Can’t stress enough how impressed I am by the TH900.
If you can find one on the used market and are in to EQ I highly recommend giving this a try.
Works great on Mogwai tube amp from the 8ohm tap.
4 Likes