This study explores connections between Inca musical performance practices and acoustic spaces. Drawing on historical sources, and informed by contemporary ethnographic perspectives, it considers a variety of Inca performance contexts, including ushnu platforms, royal palaces, and Haucaypata – the large square at the heart of the Inca capital, Cuzco. As a starting point it examines the large ushnu platforms that were built by the Incas in several parts of the empire, arguing that rather than acting as “stages” for musical performance per se, such monuments probably served as important foci for ceremonial activity, involving participatory music and dance. The existence of outside and inside music making is then considered, initially through revisiting an influential account of Inca acoustics by Robert Stevenson (1968), which leads to discussion of the musical implications of Inca life-style and architectural acoustics. Various examples are used to raise questions about how Inca musical sonorities were adapted to particular acoustic environments. In turn, it is speculated whether the Incas developed an elite chamber music culture – adapted to resonant interior spaces – comparable to that of, for example, medieval Europe.