Fostex TH919

Fostex TH919 is Fostex's flagship next-generation open-back dynamic headphone, launched in the second half of 2025 as the direct successor to the TH909 and the top dynamic model in the TH Premium Series. The 50mm BioDyna mk2 driver features an updated voice coil and reinforced diaphragm surround, the solid Japanese maple housing carries Urushi lacquer with a sulfur-smoked silver foil pattern, and the open chamber uses double-layer precision-machined aluminium apertures. Magnesium alloy mechanical components reduce weight by approximately 20% compared to the aluminium used in the previous generation. Mk2 earpads in a new dual-layer configuration with silk protein and sheepskin leather. Hand-assembled in Japan.

BioDyna mk2 driver and open chamber with double-layer aluminium apertures

The 50mm BioDyna mk2 transducer in the TH919 is the updated version of the TH909 unit — a new voice coil and reinforced diaphragm surround reduce distortion and artifacts in the bass range while fully preserving the character and resolution of the predecessor. Magnetic flux density: 1.5 Tesla. The bio-cellulose and composite fiber diaphragm with a free-edge design delivers a frequency response of 12.5–40,000 Hz — this range differs from the TH909 specification (5–45,000 Hz) and reflects updated housing tuning. The TH919's open chamber uses double-layer precision-machined aluminium apertures with a calibrated opening ratio — the same technique as in the TH1100RPmk2 — for an optimal balance between soundstage width and resonance control. Impedance: 25 Ω, sensitivity: 100 dB/mW, maximum input: 1,800 mW. Weight: approx. 385 g.

Japanese maple with Urushi lacquer and sulfur-smoked silver foil: Sakamoto craftsmanship on a new platform

The solid Japanese maple housing — a hard maple with acoustic properties comparable to lutherie tonewoods — is finished with Urushi lacquer by the Sakamoto Otosho Shoten factory, established in 1900. In the TH919, Fostex applies a sulfur-smoked silver foil technique over the base black lacquer: several types of foil applied in a torn-paper manner build a multi-layered depth and a unique pattern per unit. Mechanical components including the base plate and yoke are machined from magnesium alloy — approximately 20% lighter than the aluminium used in the previous generation. Mk2 earpads: dual-layer foam with silk protein synthetic leather covered by natural sheepskin leather — identical configuration to the TH1000RPmk2 and TH1100RPmk2. Included cable: 2 m, 7N OFC, 6.3mm plug, 2-pin connector with rhodium-plated contacts on a gold-plated base. Balanced connection via the optional XLR cable (ET-H3.0N7BL) and 4.4mm cable (ET-TH4.4BL). Leather carrying pouch included.

KEY FEATURES

• Open-back dynamic design — Fostex next-generation flagship dynamic headphone, successor to TH909
• 50mm BioDyna mk2 driver: bio-cellulose diaphragm, updated voice coil, reinforced surround, 1.5 Tesla
• Solid Japanese maple housing + Urushi lacquer with sulfur-smoked silver foil (Sakamoto factory, est. 1900) — each unit unique
• Open chamber with double-layer precision-machined aluminium apertures — calibrated opening ratio
• Mechanical components: magnesium alloy — approx. 20% weight reduction vs. aluminium
• Mk2 earpads: dual-layer foam + silk protein synthetic leather + natural sheepskin leather
• Included cable: 2 m, 7N OFC, 6.3mm plug
• 2-pin connector with rhodium-plated contacts on gold-plated base
• Optional balanced cables: XLR ET-H3.0N7BL, 4.4mm ET-TH4.4BL (sold separately)
• Included accessories: leather carrying pouch
• Hand-assembled, manufactured in Japan

TECHNICAL SPECIFICATIONS

• Type: open-back, over-ear, dynamic
• Driver: 50mm BioDyna mk2 (bio-cellulose + composite fibers), neodymium magnet, 1.5 T
• Frequency response: 12.5 Hz – 40,000 Hz
• Impedance: 25 Ω
• Sensitivity: 100 dB/mW
• Maximum input power: 1,800 mW
• Weight: approx. 385 g (without cable)
• Housing: solid Japanese maple + Urushi lacquer with sulfur-smoked silver foil (Sakamoto); double-layer machined aluminium apertures
• Mechanical components: magnesium alloy
• Earpads: dual-layer foam + silk protein synthetic leather + natural sheepskin leather
• Included cable: 2 m, 7N OFC, 6.3mm plug
• Cable connector: 2-pin, rhodium-plated on gold-plated base
• Optional balanced cables: XLR ET-H3.0N7BL, 4.4mm ET-TH4.4BL
• Accessories: leather carrying pouch
• Manufacturing: hand-assembled in Japan