2006 年 62 巻 1 号 p. 12-18
The results discussed in this paper are for a sound-absorption system consisting of para-aramid paper with many small holes and an air permeability of less than 30 cm3⁄(cm2·s), attached to non-woven material with a density of not more than 0.15 g⁄cm3. A combination of non-woven fabric and para-aramid paper with an air permeability of less than 30 cm3⁄(cm2·s) achieved much better sound absorption than glass wool. Although the sound absorption of the paper attached onto the non-woven fabric (RUBA®-SA) is similar to that of the micro-perforated-panel (MPP) sound-absorption system, RUBA®-SA can reduce both of the thickness and the weight of the sound-absorption system. The paper acts as the MPP, while the non-woven fabric plays the role of the air gap at the back of the MPP.