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Overview
The T50RPmk4g is the latest model in the RP technology headphone series, which has been
continuously refined for 50 years and is used in professional music studios worldwide. Featuring
Fostex’s RP technology proprietary planar magnetic driver, it delivers an unparalleled response, resulting in exceptional sound localization and clear separation, for an unparalleled gaming experience.
The RP technology planar diaphragm driver, which has been improved over the past 50 years
and evolved into the fourth generation, has undergone significant improvements, including an increase in the number of magnets that sandwich the diaphragm and a new design for the pattern shape of the printed coil. This enables accurate and high-definition reproduction from the low to high frequency range, and delivers an outstanding sense of localization and separation with overwhelming response. This presents a distinct advantage in hearing minute sounds like footsteps, quickly and accurately locating them, and pinpointing and clearly distinguishing targets against environmental sounds and background music.
The RP technology planar magnetic driver, first developed over 50 years ago and refined continuously throughout the years, has now hit its 4th generation. A new printed coil pattern shape has been employed to expand and equalize the vibration area of the flat diaphragm. Additionally, the number of magnets that sandwich the diaphragm has been increased substantially. Furthermore, the components of the magnetic circuit have been redesigned to optimize their magnetic flux distribution, suppressing unnecessary resonance and achieving even better transient response. This 4th generation driver, developed by fully incorporating various technologies cultivated over the years, simultaneously achieves improved sensitivity, smooth frequency response, and superb transient characteristics. By accurately and delicately reproducing elements all across the frequency spectrum, the soundstage and localization have also been improved. The new driver is also more efficient, requiring less power from the headphone amplifier to achieve peak performance.
Features
• Planar Magnetic Driver
• Proprietary Regular Phase Technology
• Semi-Open Stereo Earcups
• Frequency Response of 10 Hz to 40 kHz
• Sensitivity of 97 dB
• Symmetrical Housing
• Detachable 3.5mm TRRS to TRS Cable
Generating expert take…
Fostex emerged in 1973 as the branded consumer and professional division of Foster Electric Co., Ltd., a Japanese loudspeaker manufacturer founded in 1949. Established to bring Foster's high-quality speaker components directly to dealers and customers, Fostex quickly gained international recognition through innovative products like the T20RP headphones and 6301 studio monitors. The brand's foundation rests on Foster's position as one of the world's largest OEM loudspeaker developers, employing tens of thousands across multiple countries and manufacturing millions of speaker units monthly.
The company built its reputation across three interconnected product categories: professional studio equipment, consumer headphones, and powered monitor speakers. Fostex became particularly renowned for pioneering RP (Regular Phase) technology, which delivers clear sound with high sensitivity and wide dynamic range—a signature that defines their headphones, microphones, and speaker designs. Beginning in 1978, the brand expanded into professional speaker development, eventually introducing the PM series of powered monitors and establishing itself as a trusted choice for recording studios, broadcast facilities, and serious home listeners.
Fostex occupies a distinctive middle ground in the audio market: neither ultra-premium boutique nor mass-market consumer, but rather a respected specialist brand with deep professional credentials. Their products appeal to recording engineers, studio owners, and discerning hi-fi enthusiasts who prioritize accuracy and reliability over luxury positioning. The 6301B monitor remains an industry standard after decades in production, while the T20RP headphones maintain popularity among studio professionals—testament to Fostex's enduring reputation for sonic integrity and engineering excellence.
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