Sound absorptive multilayer composite

A sound absorption's multi-layer compound can improve the acoustical property; the sound absorption's multi-layer compound with: Air-tight barrier,Ventilated reinforcing core; the reinforcing core gas resistance to flow to at least one of 100mks Rayleigh, thickness of the final and is at least about one of; Ventilated opening foam or fibre pad, the opening foams or the gas resistance to flow of fibre pad is less than of 2000mks Rayleigh, thickness of the final and is at least formed of 1/10; And semipermeability gas separating membrane, the semipermeability gas separating membrane gas resistance to flow is formed 500mks Rayleigh to about 4000mks Rayleigh. For example, a said rear and selecting and combined localization's the opening of the foam layer of air-tight barrier or the combined selecting of supporting and locating semipermeability gas separating membrane; the combined selecting and suitable locating, which can improve the existing car compartment roof lining pattern.