Art that is about sound; any artwork in which the primary medium is sound and of which the primary experience is auditory. Often site-specific (i.e., created for a particular space) and typically interdisciplinary in nature, acoustic art installations utilize a wide range of materials, devices, and techniques to produce a desired sound or set of sounds. Some acoustic art installations are interactive, requiring activation by a listener either physically (i.e., by touching and manipulating the installation) or indirectly by electronic means (e.g., by tripping a sensor or pushing a button); others are passive, requiring no interaction on the part of the listener. Acoustic art installations are shown in museums, at art galleries, and often in both public and private (usually corporate) architectural spaces, where they are intended to engage visitors in unexpected and emotionally captivating ways. (Also called Sound Art.)