A method of making an acoustic insulator includes depositing thermoplastic particulate on a first surface of a base layer. The method further includes heating the particulate such that the particulate at least partially melts and penetrates the first surface of the base layer, thereby increasing density and airflow resistance of the base layer proximate the first surface such that the base layer has an areal mass in the range of 0.1 to 1.0 kg/m.sup.2 and an airflow resistance in the range of 300 to 5,000 Nsm.sup.-3 proximate the first surface.