Speaker unit has newly developed aluminum die-cast frame based on the strength analysis by the fine element method. Stronger magnetic circuit using 200mm ferrite magnet is equipped for higher input durability and larger amplitude driving. Oval mounting hole can be adjusted between 370 to 375mm. FW405N has the compatibility with not only FOSTEX old 15” drivers but some famous woofers’ replacements. Hybrid cone paper, the zorous super damping fiber + carbon fiber mixed into tree pulp basis material, is used to realize the light weight & high stiffness diaphragm.