Fostex knows transducers better than almost anyone — and that's no coincidence. Founded in 1973 as the consumer-facing arm of Foster Electric, one of the world's largest OEM speaker and transducer manufacturers, Fostex was built from the inside out: from the diaphragm, the voice coil, the physics of sound itself. That engineering depth is what separates Fostex from brands that merely assemble.
At the heart of the brand is RP — Regular Phase technology. Patented in 1975, it's a planar design where the entire diaphragm surface moves in phase, producing sound with remarkable linearity and detail — free from the colorations typical of conventional dynamic drivers. The T50RP headphones have been a studio standard for decades, and remain the go-to platform for audiophiles and modders worldwide who want planar performance without flagship pricing.
Alongside its headphone legacy, Fostex developed its celebrated full-range drivers and BioDyna diaphragms — crafted from biocellulose, a material that is both ultralight and rigid, yielding fast, rich, and natural reproduction. These drivers have fueled a DIY speaker-building culture that remains uniquely strong in Japan to this day. When you choose Fostex, you're not just buying a speaker — you're tapping into over fifty years of transducer science.
Fostex
