The document discusses various types of acoustic materials used for soundproofing, including sound absorbers, diffusers, barriers, and reflectors. It provides examples of common materials for each type such as acoustic foam panels, fabric wrapped panels, ceiling tiles, and mineral wool rolls for absorbers. For diffusers it mentions pyramidal, quadratic, and polycylindrical styles. Barriers include mass loaded vinyl, composite foams, and metal sheet curtains. Price ranges and specifications are given for many products.