Fostex TH616 is an open-back over-ear headphone released to commemorate Fostex's 50th anniversary as a limited-edition model — CNC-milled from solid black walnut with an aperture pattern referencing traditional Japanese woodcraft and the natural phenomenon of sunlight filtering through tree canopies. The 50mm BioDyna driver with a 1 Tesla magnetic circuit positions the TH616 one step below the TH808 and TH909 (1.5 T) while sharing the same diaphragm architecture and the same wood-housing tuning philosophy. Hand-assembled unit by unit in Japan. Despite the original limited-edition designation, the TH616 has entered Fostex's regular global catalog and remains available through international distribution.
Milled black walnut housing: aperture geometry as modal damping tool
Each opening in the TH616's housing is precisely dimensioned to avoid generating resonance at specific frequencies — the aperture pattern is not purely aesthetic but functions as a modal vibration suppressor by eliminating surface symmetry on the enclosure. Solid black walnut has higher density and internal damping than the acacia used in the TH810/818, giving the TH616 a darker, more focused housing resonance that acoustically aligns it closer to the TH808. The baffle plate is made from high-specific-gravity resin, a material selected specifically to minimize resonance noise — translating according to Fostex into higher resolution, a richer midrange, and better-controlled bass reproduction. All mechanical components including the yoke and headband adjustment are machined from aluminium for rigidity without added weight. Internal wiring is 7N-grade OFC.
BioDyna 1 T driver, low-resilience earpads and HiFC cable
The 50mm BioDyna transducer with a neodymium magnet at 1 Tesla magnetic flux density delivers a wide dynamic range at low distortion — the lower magnetic field relative to the TH808/818/810 (1.5 T) places the driver at a different operating point, which informs the TH616's distinct bass character and transient behavior. The bio-cellulose and composite fiber diaphragm is constructionally identical to higher models — low specific gravity, high Young's modulus, high internal loss, and a free-edge design for linear large-amplitude reproduction in the low midrange. Earpads use low-resilience urethane foam covered in high-grade synthetic leather — soft, wear-resistant, and comfortable during extended sessions. Included cable: 3 m Y-type, pure copper HiFC (high-performance copper with specialized processing), terminating in a 6.3mm plug. Detachable 2-pin connector with rhodium-plated contacts on both ends. Balanced connection via the optional XLR cable ET-H3.0N7BL.
KEY FEATURES
- Open-back over-ear design — limited-edition Fostex 50th anniversary model, now in regular global catalog
- CNC-milled solid black walnut housing — aperture pattern referencing Japanese woodcraft and komorebi (light through leaves)
- Aperture geometry engineered to eliminate modal vibrations and suppress resonance at specific frequencies
- 50mm BioDyna driver: bio-cellulose diaphragm, neodymium magnet, 1 Tesla magnetic flux density
- High-specific-gravity resin baffle plate — resonance noise reduction for improved resolution and midrange
- All-aluminium mechanical components
- Earpads: low-resilience urethane foam + high-grade synthetic leather
- Detachable cable: 3 m Y-type, pure copper HiFC, 6.3mm plug
- Internal wiring: 7N OFC
- 2-pin connector with rhodium-plated contacts on both ends
- Balanced XLR connection via ET-H3.0N7BL (sold separately)
- Hand-assembled unit by unit, manufactured in Japan
TECHNICAL SPECIFICATIONS
- Type: open-back, over-ear
- Driver: 50mm BioDyna (bio-cellulose + composite fibers), neodymium magnet, 1 T magnetic flux density
- Frequency response: 5 Hz – 45,000 Hz
- Impedance: 25 Ω
- Sensitivity: 96 dB/mW
- Maximum input power: 1,800 mW
- Weight: approx. 370 g (without cable)
- Housing: solid black walnut (CNC-milled), high-specific-gravity resin baffle plate
- Mechanical components: aluminium
- Earpads: low-resilience urethane foam + high-grade synthetic leather
- Internal wiring: 7N OFC
- Included cable: 3 m Y-type, pure copper HiFC, 6.3mm plug
- Cable connector: 2-pin, rhodium-plated contacts (both ends)
- Balanced cable: XLR ET-H3.0N7BL (sold separately)
- Manufacturing: hand-assembled in Japan
