Sound absorption is responsible for ‘‘audibility’’ in a room. It dictates if a room appears ‘‘reverberant’’ or how loud a sound source seems. How do we define ‘‘sound absorption’’?

Sound absorptions refers to the reduction of sound energy in a room though a sound wave losing energy through component surfaces. The energy of sound waves is absorbed or reflected from boundary surfaces as well as objects and people within a room. The appropriate sound absorption ensures that the sound in a room is perceived as louder or quitter. The ability of a material to ‘‘swallow’’ sound waves depends on the material composition. Porous, open-cell or perforated materials normally absorb sound very well. ‘‘Good audibility’’ describes the conditions in a room that enable the best possible transmission from a sound source to a listener.