Fostex / T50RPmk4Q

<> The “T50RPmk4Q” is a studio reference model designed to deliver “authentic sound.” Combining 4th-gen RP drivers with 7N high-purity copper wiring, it delivers incredible responsiveness and precise sound localization. It accurately reproduces sound attack and subtle nuances, providing a stress-free, high-quality audio experience for precision-driven music production.

Based on the “T50RPmk4”—which has garnered support from many creators and listeners thanks to its proprietary, full-drive planar magnetic “RP” driver, developed in-house and refined through use in professional music studios around the world—a new high-fidelity model, the “T50RPmk4Q,” has been developed. This series inherits the design philosophy cultivated in the series’ flagship model, the “T60RPmk2ai.” For the internal wiring connecting the heart of the system to its extremities, we’ve adopted 7N-grade high-purity copper wire with a purity of 99.99999% or higher, elevating the RP driver’s excellent response performance, subtle nuance reproduction, and spatial reproduction capabilities to an even higher level. While maintaining the Monitor Identity’s heritage, the “T50RPmk4Q” serves as a studio reference model that vividly renders sound localization and attack, demonstrating its true value in production environments where authentic sound is essential.


■ 7N-grade internal cable inherited from the “T60RPmk2ai”
Inheriting the high-fidelity design philosophy of the series’ top-of-the-line model, the “T60RPmk2ai,” the driver and connector are connected via 7N-grade high-purity OFC (Oxygen-Free Copper) cable with a purity of 99.99999% or higher. This represents a significant increase in purity compared to the 3N-grade cables used in the T60RPmk2 and T50RPmk4, elevating the RP driver’s excellent response performance, subtle nuance reproduction, and spatial reproduction capabilities to an even higher level.

■ 4th-Generation RP Driver
The fully-driven planar diaphragm driver, based on RP Technology—which has been refined over 50 years using in-house technology—has been updated to its 4th generation. To expand and uniform the vibration range of the planar diaphragm, the number of magnets sandwiching the diaphragm has been increased, and the pattern of the printed coil has been redesigned. Furthermore, by completely redesigning the magnetic circuit components to optimize magnetic flux distribution, unwanted diaphragm resonance is suppressed, resulting in sharp attack and decay with crisp response. Developed by fully incorporating the diverse technologies cultivated over the years, the 4th-generation driver simultaneously achieves improved sensitivity, a smooth frequency response ideal for monitoring, and excellent transient response. By enabling accurate and delicate reproduction from the deep bass to the high frequencies, we have further improved sound localization and soundstage reproduction compared to previous models. Furthermore, as with previous models, we ensure reliable quality through integrated manufacturing at our own factory.
*RP and RP Technology refer to Fostex’s proprietary technology (Patent No. 7675248) that moves the entire surface of the planar diaphragm with a regular phase (Regular Phase).

■Easy Support for Balanced Connections
The T60RPmk2Q uses a Y-cable connection, with 2-pole 3.5 mm connectors on the left and right housings. The separately sold balanced cable is the φ4.4: ET-RP4.4BL2Y.
The T50RPmk4Q is equipped with 4-pole 3.5 mm connectors on both the left and right housings, allowing cables to be connected to either side. A separately sold balanced cable (φ4.4: ET-RP4.4BL2.0) is available.

■ “Kyū” Logo Housing Exclusive to the Q Series
The housing features a logo symbolizing the design philosophy of pursuing the ultimate in sound quality.

■ Ear Pads for Comfortable Fit
The ear pads feature a low-resilience, around-ear design optimized for comfort, ensuring a comfortable listening experience even during extended use. Additionally, you can install the separately sold optional ear pads made with Toray’s Ultrasuede? (EX-EP-RP-SUEDE). These pads are breathable, soft to the touch, and deliver smooth, high-quality sound across the entire frequency range, from deep bass to high frequencies.


Type: Semi-open dynamic
Driver: RP-type planar diaphragm
Impedance: 28 Ω
Sensitivity: 97 dB/mW
Maximum Input: 3,000 mW
Frequency Response: 10–40,000 Hz
Unit Weight: Approx. 330 g (excluding cable)
Cable: φ3.5 mm (4-pole) ⇔ φ3.5 mm (3-pole) stereo OFC cable (2 m) × 1, φ3.5 mm → φ6.3 mm stereo adapter × 1
Included: Safety Precautions, Quick Start Guide

■ Precautions for Use
　After use, wipe off any sweat, sebum, hair styling products, foundation, etc., that has adhered to the ear pads or head pads with a dry cloth.
　Ear pads are consumable parts. They will deteriorate due to daily use or long-term storage, so please replace them as needed.