This essay examines interconnections between postwar racialization, U.S. citizenship, and audio technology through a cultural history and analysis of the tape recorder’s emergence in the 1950s. Combining sound studies, critical race studies, cinema studies, and the history of technology, I trace how the recorder frequently functioned as a metonym for reproducing appropriately nationalized bodies, especially in the 1955 film Blackboard Jungle. In the film, English teacher Richard Dadier tries to use the recorder to “quiet a class of screaming animals”: the working class, racialized students at inner-city North Manual High. Relying on the machine’s advertised ability to produce obedient silence and proper sound, Dadier is frustrated by the students’ resistance; they thwart him by pushing heavily accented Pete Morales to the microphone. While Dadier’s pedagogy ultimately backfires, the struggle over Morales’s recording exposes sound and audio reproduction technologies as key modalities of national and racial identity formation.