A sound absorption model of kapok-based fiber nonwoven fabrics, based on the Biot–Allard model, has been developed by considering the heat conduction performance of the materials and the limpness of the fiber frame. Comparisons of sound absorption coefficients and specific surface impedance calculated by the Biot–Allard model and the new model with the measured values for four different kinds of kapok-based fiber nonwoven fabrics have been made. It is shown that the new model provides better predictions than the Biot–Allard model. The new model may be the theoretical foundation for the design of industrial products for kapok materials.
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