The SR-X9000 represents the pinnacle of Stax electrostatic earspeaker engineering, featuring the revolutionary MLER-3 fixed electrode technology—a four-layer construction combining mesh and etched electrodes bonded through thermal diffusion. This breakthrough, refined over two decades of research, delivers a rigid, resonance-resistant structure that transmits sound with unprecedented clarity. The diaphragm, crafted from ultra-thin engineering film and 20% larger than the SR-009S, achieves exceptional transient response and extended high-frequency performance while maintaining minimal mass. Precision-machined aluminum housings eliminate vibration, while the intelligently designed guard mesh with variable-height pillars controls reflection angles for seamless sound propagation. Premium materials throughout—genuine leather ear pads and headband, stainless steel arc assembly, and 6NCu ultra-pure copper cabling—ensure both sonic excellence and lasting comfort. Includes two interchangeable cables and paulownia wood storage case.