Field Test · Studio Gear Review
Fostex T50RPmk4CL
In-depth look at Fostex’s semi-open planar magnetic headphones
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Spec Sheet
- Wired headphones
- Circumaural
- Closed-back design
- Magnetostatic
- Frequency response: 10 Hz – 40,000 Hz
- Impedance: 28 Ohm
- Sound pressure level: 97 dB
- Driver: RP Planar Magnetic 4th generation driver
- Maximum power rating: 3.000 mW
- Single-sided, detachable cable (can be plugged in on the left or right)
- Weight (without cable): 330 g
- Includes 2 m cable from 3.5 mm stereo mini jack to 3.5 mm stereo mini jack, 3.5 mm to 6.3 mm adapter
Studio Log
| Available since | September 2025 |
|---|---|
| Item number | 626476 |
| Sales Unit | 1 piece(s) |
| Design | Over-Ear |
| System | Semi Open |
| Impedance | 28 Ohms |
| Frequency range | 10 Hz – 40000 Hz |
| Adaptor | Yes |
| Replaceable Cable | Yes |
| Colour | Black |
| Max. SPL | 97 dB |
| Type Of Connector | Mini Jack |
| Weight | 330 g |
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Customer Review Summary
[META]Explore the Fostex T50RPmk4CL headphones’ design, specifications and performance potential in this detailed technical review.Introduction to the Fostex T50RPmk4CL
The Fostex T50RPmk4CL is a wired, circumaural headphone model released in September 2025, featuring a semi-open system and advanced planar magnetic driver technology. Priced at £206, it is designed for audio enthusiasts requiring a balance between clarity, power handling, and user flexibility.
Build and Design
The headphones present a closed-back, over-ear design encased in a sturdy black shell weighing 330 grams without the cable. Manufactured by Fostex, the T50RPmk4CL aims to provide a semi-open acoustic environment, which can affect soundstage and isolation performance.
The choice of a circumaural fit enhances comfort and passive noise reduction, while the single-sided detachable cable can be connected from either side, promoting usability and ease of replacement. The package includes a 2-metre cable terminating in a 3.5 mm stereo mini jack, complemented by a 3.5 mm to 6.3 mm adapter, making it compatible with a wide range of audio sources.
Audio Specifications
- Driver Type: Fourth generation RP planar magnetic
- Impedance: 28 Ohms, which suits both portable and stationary equipment without requiring a dedicated amplifier
- Frequency Response: 10 Hz to 40,000 Hz, significantly broader than the typical audible range, suggesting capability for detailed high-frequency reproduction and extended bass
- Maximum Sound Pressure Level (SPL): 97 dB, adequate for safe listening volumes with minimal distortion
- Maximum Power Rating: 3,000 mW, indicating robust tolerance to power and dynamic headroom
Planar Magnetic Drivers
The use of fourth generation planar magnetic drivers is a defining feature. Such technology utilises a thin diaphragm suspended between magnets, allowing for precise control over the driver’s motion and reducing distortion. This suggests the T50RPmk4CL can deliver detailed sound reproduction with consistent response across the frequency spectrum.
Compared with dynamic drivers, planar magnetic units typically provide quicker transient response and improved clarity, especially in mid and high frequencies, which can support critical listening environments.
Connectivity and Flexibility
The inclusion of a detachable cable adds convenience for users who wish to replace the cable due to wear or upgrade it. The dual compatibility with both left and right ear cable insertion enhances user preference and comfort.
The mini jack connectors fit most consumer devices and professional audio equipment, while the adapter expands usage to studio-grade headphones outputs.
Weight and Comfort Considerations
Weighing in at 330 grams without the cable, the headphones are moderate in weight for circumaural models with planar magnetic drivers. This weight suggests potential for long listening sessions without excessive fatigue, assuming good ergonomics in the headband and ear cup padding design.
Intended Audience and Usage
The T50RPmk4CL appears targeted at audiophiles and professional users who require detailed and accurate sound reproduction with the convenience of flexible connectivity. The semi-open design may offer a balance between sound isolation and natural soundstage, suitable for both private listening and studio applications.
Conclusion
The Fostex T50RPmk4CL combines a semi-open, circumaural design with advanced fourth generation planar magnetic drivers, delivering a broad frequency response and durability for various audio setups. Its impedance and power rating ensure compatibility with a wide range of audio sources without necessitating specialised amplification.
While lacking any user feedback at this stage, the headphone’s specifications indicate a capable and versatile audio device positioned at a reasonable price point within its category. The detachable cable and included adapter answer practical needs, making the T50RPmk4CL a technically compelling choice for discerning listeners seeking planar magnetic performance.
