Sonic City is a wearable system for creating electronic music based on sensing bodily and environmental parameters. Context and user action are mapped to sound processing parameters and turn live concrete sounds into music. Thus, a personal soundscape is co-produced by a user’s body, local activity and urban ambiance simply by walking through the city. Encounters, events, architecture, weather, (mis)behaviours – all become means of interacting with, appropriating, or ‘playing the city’.