This article discusses space and interactivity in relation to some of the author's compositions for performers and computer. It outlines approaches to musical space relevant to those works arising from the realms of acousmatic, instrumental/acoustic and soundscape composition, and explores the conflict arising when a variety of listening practices are employed by the spectator-listener. This conflict challenges the perceived boundaries that differentiate genres, and also challenges the significance of existing ‘instrumental' definitions of interactive computer music to the author's work. The author's approach to investigating this issue through composition is discussed, using two pieces as examples: Words on the streets are these (2001), an interactive installation, and Still Life (2002), a concert piece for string quartet and live electroacoustics. Technical and aesthetic aspects are outlined, specifically in relation to the experience of the spectator-listener. The overall aim is to emphasise the importance of considering spatial issues in composing interactive music, and to examine how the interplay of spatial concepts might be explored in practice.