The following article discusses the Sound Archive of the Ruhr. Our project touches upon a set of questions that are of interest to sound studies. They concern intention and modes of archiving sound, working for museums, exhibitions, film, theatre productions, education and science, recordings as testimony as well as cultural heritage. Working on and with the archive made us sensitive to the aurality of the confined space and to the horizons of meaning that people attributed (and still attribute) to the acoustic dimensions of their everyday life. As a result, we began to conceptualize history based on the sensual constitution of reality and thus were able to take a different view of social transformations. The sounds in the Sound Archive of the Ruhr are not “sensitive” like surveillance tapes that document state repression and blackmail, uncover political scandals or are used for propaganda purposes. These sounds are sensitive because they are endangered and therefore should be recorded with respect for cultural heritage. Moreover, they raise questions about the political power, which defines when and how sound is considered noise in a changing social order.