Acoustical characteristics of perforated panels with cover membranes

In this paper, the acoustical characteristic of perforated panel with cover membrane is theorectically investigated. Based on the fundametal principle of acoustics, the expressions of reflecting the sound transmisson of this construction are derived and the formulas of calculating the specific acoustic impedance are obtained. We also discuss the changesof specific acoustic resistance with some important 'parameters, such as the frequency, the thickness of air layer and the surface density of the membrane. A good agreement betweenpredicted results and measured data is illustracted