Material selection is foremost design parameter in providing acoustical comfort levels in both acoustically sensitive and noise generating spaces ranging from the small size meeting halls to large scale multipurpose auditoriums and even from foyers to shopping malls. Architects usually prefer seamless, unperforated materials in line with their interior design concepts. One of the objectives of this research is to contribute to the market portfolio of smooth faced, seamless acoustical materials with highest sound absorption performances. Another objective is to develop such a composition with ecological and sustainable ingredients, and binding techniques. Energy efficient and sustainable materials are frequently devised in construction industry for acoustically sensitive environments to get credits for international certification procedures such as LEED and BREEAM. Nevertheless, most of the acoustic materials in construction industry are perforated and/or supported with mineral wool based material backing, which have an adverse effect on indoor air quality. This article is on the improvement of an ecological unperforated sound absorptive material which is made of reed and pumice stone layers. The feasibility and effectiveness of a proposed configuration have already been studied. This paper seeks ways of optimizing number and thicknesses of different material layers in attaining maximum sound absorption performance.