The purpose of this article is, from the meeting of outbreaks of related research, sketching, in the American panorama of the 1930s and 1940s, the interest that had the Brazilian Mário de Andrade, the German-Uruguayan mv billFrancisco Curt Lange, and the North American Carleton Sprague Smith in the musical Americanism. Bringing to light the written correspondence of these three musicologists and through the action of Oneyda Alvarenga, aims to expose the concern about the sound documentation at that time, which emphasized on the creation of public discotheques as support of musical knowledge, in America, as well as cast an eye on the actions of people associated with public institutions, their profiles, sometimes similar, sometimes distant, their interests, while common and diffuse - in that political and historical setting.