A sound absorptive multilayer composite having an air-impermeable barrier,
an air-permeable reinforcing core having an airflow resistance of at
least about 100 mks Rayls and a thickness at least about 1/3 the final
composite thickness, an air-permeable open cell foam or fibrous pad
having an airflow resistance less than about 2000 mks Rayls and a
thickness at least about 1/10 the final composite thickness and a
semipermeable airflow-resistive membrane having an airflow resistance of
about 500 to about 4000 mks Rayls can provide improved acoustic
performance. For example, existing vehicular headliner designs may be
improved by adding a properly chosen and properly positioned
semipermeable airflow-resistive membrane, a properly chosen and properly
positioned air-impermeable barrier, or a properly chosen and properly
positioned open cell foam layer.