Revaluation of wastes in the soundproofing material domain has a major international and national importance from a technical, economical and ecological point of view. This paper presents researches on the determination of the sound absorption coefficient dependent upon frequency, for every sample, thus determining the phonic absorption capacity of every resulted material. Materials were obtained by including some materials considered as wastes – pine sawdust and recycled rubber particles, in a polymer type organic matrix. The samples were made of reinforcement material and polyurethane binder, in different proportions and of different thicknesses.