The sound absorption materials have been used to enhance the performance of a noise barrier and improve the room acoustics. In this study, 6 products of sound absorption materials generally used in Korea were chosen, and their absorption performance was tested in various conditions, that is, it was measured while changing thickness, density and air-gap in their back, and measured with or without facing on their face. 攀†책임저자;정회원, 국립환경과학원 교통환경연구소E-mail : djkang@me.go.krTel:(032)560-7676, Fax:(032)560-7678* 국립환경과학원 교통환경연구소攀攀