Selecting the correct core material is vital for sound performance. Fiberglass (Rigid Glass Wool) is the industry standard for high-frequency absorption, while Rockwool offers excellent fire resistance and mid-low frequency dampening. For eco-friendly projects, Polyester Fiber (PET) panels are non-toxic and easy to install, though they may have a lower Noise Reduction Coefficient (NRC) than mineral wool. Ensure the material density is at least 96kg/m³ for fiberglass or 48kg/m³ for polyester to ensure effective sound treatment.