The acoustics of a building refers to the sound quality within a given space and the ability of sound to travel within the space. Different materials and building elements affect the acoustics of a building. For example, hard surfaces such as concrete or tile will reflect sound, while softer materials such as carpet or acoustic panels will absorb sound. The shape of the room also affects how sound travels within the space. A rectangular room with parallel walls will be more reflective than an irregularly shaped room. The arrangement of furniture, wall hangings, and other objects can also affect the sound quality of the space.