Requirements concerning adjustment of acoustical parameters are nowadays more and more frequently numbered among design assumptions adopted for newly constructed concert halls and other auditoriums planned to play dierent functions. Investors usually require that the newly designed interiors can be used for such dierent purposes as playing orchestral music, performing theatre spectacles, screening movies, or holding lectures. This means the necessity to undertake studies on new technologies allowing to excert eective control over acoustics of multipurpose auditoriums. This paper proposes to use acoustic curtains as an eective means of modication of acoustic absorptivity of rooms. A design solutions for such curtains is described together with basics of the theory allowing to predict their acoustic properties. Results of sound absorption coecient calculations performed for selected systems on the grounds of airow resistivity values assumed for the used fabrics are veried by means of results of measurements performed in the impedance tube. It is proven that double-layer curtains show more balanced sound absorption characteristics compared to single-layer curtains and therefore represent a more convenient option when used for acoustical adaptation of rooms. Based on model studies, design solutions with double-layer curtains is developed for two concert halls that allow to adjust acoustic properties of the interiors to the required functions.