More than one hundred private and public archives from around the world have made their holdings available. The majority of the non-commercial recordings comes from the Archives de la parole (Paris), the Musée d’ethnologie (Paris), the Phonogramm-Archiv (Berlin), and the Humboldt Universtät (Berlin). These include some 750 cylinders and discs that have never been available before outside the respective research archives.
Add to that the „commercially“ issued ethnic recordings that have apparently survived only in single copies, such as those by the Pygmies from the Scarborough Museum Trust, West African religious and ethnic music from EMI Archives Trust, and Ethiopian recordings from a family estate. About half the boxed set is devoted to ethnic recordings unknown even to dedicated ethnologists.
The other half is devoted to African-American music on commercial records found mostly in private archives, notably the Berresford, Lotz, and Schmauder collections, complimented by images provided by Tony Hagert Vernacular Music Research.