Fostex TH-909 Flagship + J.Z Edition MOD

The Fostex TH909 is a premium headphone with excellent sound characteristics and high wearing comfort. 50mm “Biodyna” diaphragms, neodymium drive with a magnetic flux density of 1.5 Tesla (15,000 Gauss) and an open style with adapted acoustic design and an extended sound field contribute to the listening pleasure.

The result is an impressive dynamic level and a high level of detail for maximum listening pleasure. The low-resilience urethane padding is perfectly adapted to head shape, as well as the headband being flexible enough to ensure excellent wearing comfort.

The design is based on dual-layer metal grilles, which are not only an eye-catcher, but also enrich the sound thanks to their low resonance. The cabinet itself is made of Japanese ornamental Cherry Birch and has been refined with an Urushi lacquer in traditional Japanese handcraft.

As the new Fostex flagship, the TH909 constitutes one finely-crafted headphone.  But as an open-back successor to the TH900 Mk2, it represents an even greater accomplishment.  The sound, while more open and spacious in accordance with the open-back design, also enhances the natural, dynamic sound that originally marked the TH900 Mk2.

And despite this improved sound quality, the TH909 remains easy to drive with that 25 ohm impedance.  The fact that you can push this headphone with a lower-power device like a phone or a computer sans amplification is impressive.

The only real downside (if you even wish to call it that) is the TH909’s tendency to reveal almost too much detail at times.  On sub-par recordings, or older recordings, this headphone can uncover limitations of the original recording.  Or, in the case of some of my favorite hip-hop test tracks, analog static and pops from producers’ samples.

Their Total Harmonic Distortion (THD) is extremely impressive, at just 0.16% THD this is the lowest I’ve recorded so far, with any headphones, including ones that are costing 3 times their price. Notice the super-low distortion in the treble, very impressive if you ask me.

Waterfall and spectral decay are showing a super-short driver vibration and an instant decay of the notes, especially the treble decay feels lightning fast, which is exactly what I’ve experienced while listening to them.

Spectrogram is not showing some weird driver movements in the bass, which is nice to experience and you can clearly see the hot zones (Red) and the smaller dips (Green) in the FR.