The article follows a discovery in the Swiss sound archives: the ‘bruitages’. Bruitages are field recordings; real world sounds from places and events in Switzerland used in radio production. They represent a documentary media practice which is based on sonic ambiances. In the context of radio, sonic ambiances are then positioned threefold: as a documentary and handcrafted practice, as a bodily performance in local space, and as a perceptive phenomenon. This leads to an understanding of ambiances as mediatized interactions between humans and their environment, resulting in specific media practices. The article concludes by considering whether a deeper understanding of ambiances could influence the media-critical debate about the realisation of the UNESCO intangible cultural heritage convention.