In this paper I present an account of musical arousal that takes into account key demands of formalist philosophers such as Peter Kivy and Nick Zangwill. Formalists prioritise our understanding and appreciation of the music itself. As a result, they demand that any feelings we have in response to music must be directed at the music alone, without being distracted by non-musical associations. To accommodate these requirements I appeal to a mechanism of contagion which I synthesize with the expectation-based arousal mechanism proposed by Leonard Meyer. This account connects musical expressivity and arousal in a way that formalists have rejected, but I argue that it provides the best explanation of our observations of listener responses while also focusing on the music itself.