The common metaphor of electronic sounds as lively and differentiated individuals emerged alongside developments in scientific modernism and industrial capitalism. Through widespread applications of graphical methods by scientists in the nineteenth century, sounds and living bodies became similarly legible through waveform representations: characterized by extensions into space, fluctuations over time, part-whole relations, and associated aesthetic variations. This knowledge was advanced by the German scientist Hermann von Helmholtz, whose work was central to the emerging fields of acoustics and electronic music in the United States by the early twentieth century. During a period of American history in which industrialization and urbanization engendered new patterns of encounter, audio-technical practitioners learned to distinguish individual sounds by aesthetic signifiers, like purity and deviation, that marked such social differences as race, class, and gender. I frame this history with a feminist theory of technological worlding, proposing that the “worlds of sound” made in audio-technical discourse are spaces of encounter and contestable realms of cultural politics.