Fostex T50RPmk4 Semi-Open Planar-Magnetic Studio Headphones

The T50RPmk4 is the fourth generation of the RP headphone that has been a studio fixture for four decades. Its planar-magnetic diaphragm is a copper-etched film driven evenly over its whole surface, and for this revision Fostex reworked the printed coil pattern and added magnets to reshape the flux across the diaphragm. The practical result is a 28 ohm load and 97 dB/mW sensitivity, down from 50 ohms on the mk3, so a laptop headphone jack or a portable recorder now drives it to a usable level.

The housings are symmetrical and both accept the 3.5 mm 4-pole plug, so the detachable cable can be run down whichever side suits the desk. Thicker low-resilience ear pads carry the 330 g over a long tracking or editing session. A 2 m stereo cable and a 3.5 mm to 6.3 mm conversion connector are in the box.