HIGHKA’s acoustic structure uses a patent-protected six-layer hollow composite design tuned for the 500 Hz–4 kHz speech frequency range. Key components are tested to 50,000+ use cycles, and the design lifespan is 8–12 years. The acoustic materials do not degrade with normal use in the way that foam-based open acoustic treatments do. The DS,A = 29.4 dB performance is a function of the structural design, not consumable materials.