The T50RPmk4 is a brand-new headphone developed by Fostex, equipped with a completely redesigned RP planar magnetic driver. Since having debuted in 1974 as part of the T50, Fostex's first ever headphones, the renowned RP driver has been featured in numerous differ-ent headphone models throughout the years. These headphones have been regarded as first-rate monitoring headphones by musicians and sound engineers all over the world. Audiophiles have also sought RP series headphones for their fantastic versatility and unparalleled value-to-performance. Featuring a new 4th generation RP driver as well as an updated, improved hous-ing design, listeners of all backgrounds can enjoy the increasingly-refined new generation of RP headphones from Fostex. 4th Generation RP Series Driver: The RP technology planar magnetic driver, first developed over 50 years ago and refined con-tinuously 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. Addition-ally, 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 tran-sient response. This 4th generation driver, developed by fully incorporating various technolo-gies cultivated over the years, simultaneously achieves improved sensitivity, smooth frequency response, and superb transient characteristics. By accurately and delicately reproducing ele-ments all across the frequency spectrum, the soundstage and localization have also been im-proved. The new driver is also more efficient, requiring less power from the headphone ampli-fier to achieve peak performance.