Sonic City is a project exploring mobile interaction and wearable technology for everyday music creation. A wearable system has been developed that creates electronic music in real-time based on sensing bodily and environmental factors - thus, a personal soundscape is co-produced by physical movement, local activity, and urban ambiance simply by walking through the city. Applying multi-disciplinary methods, we have developed the wearable from a scenario-driven, aesthetic and lifestyle perspective. A garment has been crafted for 'trying on' interaction and wearabilty options with users on-site in the city. With this prototype, we have been able to expore and rapidly iterate context and content, social and human factors of the wearable application.