Background Noise follows the development of sound as an artistic medium and illustrates how sound is put to use within modes of composition, installation, and performance. While chronological in its structure, Brandon LaBelle's book is informed by spatial thinking - weaving architecture, environments, and the specifics of location into the work of sound, with the aim of formulating an expansive history and understanding of sound art. At its center the book presupposes an intrinsic relation between sound and its location, galvanizing acoustics, sound phenomena, and the environmental with the tensions inherent in what LaBelle identifies as sound's relational dynamic. For the author, this is embedded within sound's tendency to become public expressed in its ability to travel distances, foster cultural expression, and define spaces while being radically flexible. This second expanded edition includes a new chapter on the non-human and subnatural tendencies in sound art, revisions to the text as well as a new preface by the author. Intersecting material analysis with theoretical frameworks spanning art and architectural theory, performance studies and media theory, Background Noise makes the case that sound and sound art are central to understandings of contemporary culture.