This paper considers the early work of Alvin Lucier and its often problematic positioning between concert and installation work as a means of questioning how installation might be defined. Following an introductory survey of Lucier's work, a history of installation in the visual arts is traced through the debate, initiated by Michael Fried, on the ‘theatricality' of minimalism. Fried's condemnation of the role of the viewer in what he termed ‘literalist' art became, contrary to his intentions, a central element in thinking about installation work. Fried's position was recently engaged again by Hal Foster in positing a particular phenomenology of minimalist work, which is seen to be directly relevant to the example of Lucier. Having thus established the relevance of this phenomenology to the consideration of sound installations, whether they are themselves minimal works or not, discussion returns to the problematic example of Lucier, and the conclusion that the boundary between concert and installation works may always be permeable, that a precise morphology of installation will remain elusive.