This article investigates the process by which the echo became one of the most prominent objects of study in early modern acoustics. Presenting a variety of scholarly work in seventeenth-century Europe, I argue that echo research in the period did not distance itself from the echo's place in mythology and natural history. On the contrary, the echo's existing function as an object of myth and curiosity helped it to attract attention in early modern scholarship. New methods of provoking, measuring, and calculating echo effects emerged, accompanied by descriptions of the echoes' local environments and representations of echo effects in books, journals, and questionnaires. As a much-discussed topic in the newly established scientific academies, echo research contributed to the formation of acoustics as a scientific discipline. Yet the echo remained an elusive object throughout the seventeenth century, driving questions on the nature of sound in a wide range of fields, and bringing together early modern fascinations with curiosity, mythology, and measurement.