The E.S.R.A. is concerned with the ongoing development of an online archive of digital copies of the extensive collection of rare, often unique, historical ethnographic sound recordings at the Institute of Systematic Musicology, University of Hamburg. The E.S.R.A. is aimed at safeguarding our audio heritage by providing researchers in Systematic Musicology and Ethnomusicolgy as well as cognate disciplines with high-resolution sound files and according metadata in a semantically integrated and easily accessible format. The collection of historical ethnographic sound recordings at the UHH Institute of Systematic Musicology dates back to the year 1910 and comprises several thousand individual recordings of music and speech from all parts of the world, with a distinct emphasis on the musics of Africa and the Near and Middle East. It is the stated aim of the E.S.R.A. to tranfer the sound on these often fragile carriers into the digital domain with the utmost care, developing proprietary methods of playback and digitization to ensure the highest possible degree of fidelity to the source medium. The E.S.R.A. furthermore addresses the requirement for sustainable and interoperable access strategies to sound archives’ digitized holdings by developing novel methods of computational analysis and advanced formats of representation of the archive's digitized assets to provide researchers with state-of-the-art data to approach the causative questions regarding similarities and divergences hidden in the deep structure of the manifold manifestations of musical expression in the world.