Well, well, well – the Fostex TH-X00 Mahogany has been talked about countless times and was reviewed almost just as often. Why add another review to it? Welp, why not, that’s why. I won’t bother you with lame and boring company etc. info since a) you likely know them anyway, and b) if you’re really interested in this headphone, then you have likely done your own research.
I bought my TH-X00 Mahogany new (I never buy used headphone-related gear because I find that disgusting) in 201x (don’t remember – might have been 2015) on Massdrop with my own money and paid just a tad less than €500 including import fees (in total, it was €498.xx if my memory serves me right). I reviewed the woody some time later – in a different language. Now I have translated large chunks of that very review into English and yeah, here it is.
If some sentences appear weird to you, then it’s likely either because I’m not a native English speaker, or because parts of the review and some sentences were machine-translated (even though I re-read every translated sentence and corrected a lot).
Looks, Feels, Build Quality:
Great looks and build. Light weight thanks to magnesium. Nice wood grain and varnish. Slight visual minus: wooden “gap” between magnesium frame and cups not varnished.
Permanently attached cables – would have wished for replaceable ones at the price point and no cloth/suede/nylon/whatever-it-is coating above the y-split, but whatever.
I have large ears. Nonetheless I am surprised to say that I can the soft ear pads to seal well and achieve a comfortable fit.
Clamping force is rather moderate, nonetheless the headphone doesn’t really move unintentionally.
Those who intend to use the Fostex outside should reject this idea directly, because even if the TH-X00 is a closed headphone at first and second glance, it has a surrounding ventilation slot on the magnesium ring. Correspondingly, it only isolates very moderately - a laptop's fan noise is slightly attenuated, but even a relaxed use in the garden on a sunny summer's day is impossible if you want to isolate yourself from the environment.
The Fostex is clearly a fun headphone with a present, impactful low-frequency accentuation, especially in the mid- and sub-bass, combined with an accentuated upper treble. If you are looking for a linear or mostly modest tonal tuning, the TH-X00 is clearly the wrong choice.
Nevertheless, it does not exaggerate excessively with the tuning otherwise, even if it is still a good deal away from a natural tuning (natural in the sense of "not too far away from neutral sound" in this context).
At about 500 Hz, the accentuation of the low-frequency, which from then on rises steadily downwards to 60 Hz, where the climax is located, starts. It is remarkable that the level underneath can still be kept constant and the TH-X00 Mahogany doesn't roll down below 40 Hz, but can keep the level almost constant down to 20 Hz. That's pretty great.
Due to the fact that the accentuation of the bass range increases steadily and gradually, the sub- and midbass have more level than the upper bass and fundamental, which is why voices are not unnecessarily thickened or overshadowed. The upper and upper midbass still have a bit more volume to speak of a "pure"/exclusive sub-bass boost, although the Fostex is probably one of the few headphones, if not the only one, that comes closest to it (a pure sub-bass only elevation).
At least this gradually increasing accentuation works very well with a steadily increasing bass pressure (even if for my personal taste the upper bass and lower fundamental range could sometimes be calmly dialled back by about 3 dB, to bring out the sub- and midbass even more).
Anyway – compared to a really neutral and flat tuned listening tool, the Fostex has an accentuation in the sub- and midbass, which is about 8 dB in quantity, if you achieve a good seal, which at first glance may not even seem all that much, but actually expresses itself more strongly, because the Fostex can build up quite a lot of bass pressure (possibly also by the large drivers and the closed cabinet, but mainly since its bass elevation isn’t exclusive to the sub-bass but also features a powerful, strong midbass).
At 1 kHz there is a rather flat bump, only really noticeable with sinus sweeps, which I already know from my Fostex T50RP Mk3, followed by a small dip at 4 kHz, a small hump at 5 kHz, another small dip between 7 and 8 kHz and finally a stronger broadband emphasis between about 10 and 14 kHz.
Not all that much surprisingly due to its fun smiley-face v-shape tonality, voices appear to be rather somewhat in the background in the mix without showing any real unnatural timbre or coloration from the treble or low frequencies since the elevations are set very high respectively quite low.
Despite the emphasis, the treble is generally perceived as rather inoffensive, which is due to the fact that the boost is located very high with the placement in the starting super treble, thus bypassing typical sharpness-causing frequencies between 7 and 9 kHz.
Nevertheless, the TH-X00 Mahogany doesn't necessarily have the perfectly natural upper treble and some percussion elements sound a little thinned out, but without getting sharp at all.
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Yes, the TH-X00 is clearly a “fun” tuned earphone that is especially enjoyable for listen to electronic music, hip hop/rap, better-mastered rock and pop and drum & bass, while more intimate or voice-heavy recordings with a high focus on the linguistic content (or "typical audiophile test tootling"...) seem less suitable, while there are of course no limits to personal tuning preferences.
If you are looking for a headphone with a strong, deep reaching bass in combination with a bright, but not sharp or unpleasant starting super treble and a midrange with an overall pretty correct timbre with voices appearing overall more in the background in the mix, chances are high that you will enjoy the Fostex x Massdrop TH-X00 Mahogany (very) much! I pretty much knew what I was getting before I bought my TH-X00 Mahogany, and I wasn’t disappointed at all.
The Fostex does justice to the price in terms of resolution and delivers the performance that one would expect to find for the price.
While it doesn't quite make it into the class of a Sennheiser HD 800 (the Fostex lacks a little bit of separation in the highs and the last bit of tightness in the bass compared to Sennheiser's open-bacl dynamic driver headphone flagship), it surpasses popular ‘phones such as the Beyerdynamic DT770 Pro (250 Ohm) or Meze 99 Classics in terms of overall resolution.
All in all, I see the TH-X00 Mahogany more or less slightly above the level of my HiFiMan HE-400 in terms of resolution, whereas that one is still somewhat tighter and faster in the bass than the Fostex, nonetheless the TH-X00 delivers more sub-bass presence for sub-bass enthusiasts due to the gradually increasing accentuation in its lows (although sub-bass enthusiasts should also enjoy the HE-400 because just like my Audeze LCD-X, it manages to extend its bass linearly into the sub-bass without rolling off) and it isn’t soft in the bass at all but rather tight for a dynamic driver model, and especially very well controlled.
The bass of the TH-X00 remains well controlled and nimble despite the powerful boost, even with faster and more demanding recordings. The headphone with dynamic drivers even belongs to the faster and tighter models and only appears a little soft in comparison to the tight dynamic bass of the Sennheiser HD 800 or tight bass of the orthodynamic HiFiMan HE-400.
The midrange resolves well and only appears a little “dry”/matte due to the v-shaped tuning - on the other hand, there is absolutely no lack of details in the mids, and speech intelligibility or the resolution of smaller linguistic and vocal details don’t leave anything to desire.
The treble of the headphone that emerged from a collaboration between Fostex and Massdrop, does not lag behind the midrange and bass in terms of details either and does not seem strident or sibilant due to the skilfully done placement of the accentuations as well as due to the good level of details. One could perhaps only criticize the fact that high treble notes appear to fade away a little too quickly and that separation up top, if you are used to in-ears with Balanced Armature drivers, does not have the same precision.
The Fostex still “wants” to be fed with rather well recorded and produced music material, since it doesn’t “harmonise” all that well with badly or flat mastered and overdriven recordings, because it doesn't exactly cover them up very well (in the presence range and middle highs, there is no smooth and “romantic” recession, making the Fostex point out flaws rather directly unlike for example the LCD-X where bad-ish recordings are still listenable thanks to where its recessions and dips placed in the presence range/upper midrange and treble).
For a closed headphone the TH-X00 Mahogany has, at least for my ears, a very well-done and open soundstage presentation.
In comparison with some popular open headphones up to about 400€ (for example Sennheiser HD 600, AKG K701, Beyerdynamic DT880 Edition (600 Ohm)) the spatial reproduction of the Fostex does not appear quite as open, but rather average, but on its own it has a (very) good spatial reproduction for a closed-back-ish headphones, which is bigger and more open than with many closed headphones. Therefore, it also breaks the imaginary border within my head and extends outside.
The stage of the TH-X00 Mahogany has a very well-balanced ratio between depth and width and is by no means flat. Partly the tonal tuning contributes to this, but even with "neutralised" with the help of some EQing, the convincing impression remains and the Fostex keeps most of its spatial depth.
It's nice to note that there are no audible signs of undesired reverberation reflections at all, as some closed headphones can appear to have to a lesser or greater extent.
The stage of the Fostex also convinces me in regards to instrument separation, control of densely populated, fast and complex recordings, accuracy of layering as well as the reproduction of emptiness between individual instruments. Yeah, its soundstage is one of the Fostex’s strengths.
The Fostex x Massdrop TH-X00 (Mahogany) is a very good looking and feeling headphone that is tuned for fun and brings a powerful, deep set and well controlled (especially sub-) bass which is balanced by a high, bright but not sibilant accentuation of the beginning super treble range.
Coupled with the open and precise three-dimensional reproduction, especially noteworthy for a closed-back-ish headphone, this model, which is exclusively available from Massdrop, is a great recommendation for a fun headphone for those moments when neutrality and a modest, flat tuning are not desired.
By the way, fans of the Beyerdynamic DT770 Pro are also likely to like the Fostex very much, because in my opinion it represents a direct upgrade to that very German headphone (while having a stronger emphasis on the true sub-bass, a less unnatural/metallic high frequency range, audibly higher resolution and a more precise, more open stage).
The only things left to be desired would be replaceable cables and better isolation of exterior noise – but it seems that Fostex has taken care of the first issue with the introduction of the TH-610.