SR-X9000 is the new flagship Earspeaker that marks the pinnacle of Stax electrostatic headphones production. A major technology advancement is the “MILER-3” (Multi-Layer-Elect-Rords) - a four-layer fixed electrode combining mesh electrodes and conventional etching electrodes that are crimped by thermal diffusion bonding. The newly developed manufacturing technique matures through a 20-year accumulated research and development, allowing a rigid structure that is resistant to resonation while smoothly evolving the transmission characteristics of sound compared to conventional multilayer fixed electrodes.