This paper explores the social origins and development of music relayed through loudspeakers in British factories during World War Two, focusing on the BBC programme Music While You Work, which provided a national soundtrack for factory work, and the contemporary institutions of Industrial Psychology, which promoted music as a highly ‘valuable’ accompaniment to work and formulated scientific principles governing its broadcast. Combining archival evidence from these organisations, the paper first outlines the historical circumstances of development, detailing the form of broadcasts and of the music itself. Subsequently, the causes of music's introduction to the factory are analysed. The central argument advanced is that the music resulted centrally from top-down initiatives from a ‘human relations school’ coalition of institutions and individuals, in which the aims of increased productivity and the humanisation of the workplace intermingled, but in which the aim of increased productivity dominated. Concluding remarks assess the argument and relate it to the growing literature on contemporary practices of the sound-tracking of social life.