This dissertation explores the mutual construction of voice and public sound in Japan's interwar period through the study of poetics, acoustics, and musical performance. Due to the era's coincident advent of mass sound media and imperial expansion, it proposes that the human voice and its attendant mediation through radio and phonography became a site where the social tensions of colonial capitalism—racial and linguistic difference, migration and displacement, and the limits of the public sphere—found articulation as matters of rhythm, tonality, and noise. Against these conditions, it examines how an emergent cast of poets, orators, singers, and acousticians channeled the insights and affordances of aural media toward new forms of public expression—ones that took the newly audible contours of the human voice as the basis for reshaping the semiotic and sensory boundaries of the body politic. Across its four chapters, this dissertation traces the liaisons of vocal sound, technology, and language that defined the audiovisual contours of public performance, and by extension, the cultural politics of the era. These liaisons in turn link the efforts of poets and rhetoricians to develop experimental forms of radio poetry in the 1920s and 1930s to the vocal innovations of Japanese, Japanese American, and Black recording artists at the height of Japan's transpacific jazz age. In so doing, however, it casts an ear to how such linkages formed within and against the volatile sonic borders of the imperial metropole, where post-WWI patterns of colonial migration transformed the phonic signals of accent and intonation into frequencies of racialized difference that often exceeded the purchase of vision. With such modalities of attunement unfolding against state efforts to delimit the sensory boundaries of the public sphere, this dissertation then considers the role of these vocalities in shaping the development and theorization of mass sound media in Japan at both audible and, at times, infrasonic levels.