The digital curation of ethnic music audio archives: from preservation to restoration

In the sound archive field, a long-term maintenance of the collective human memory in its original form is not sustainable. All physical carriers are subject to degradation and the information stored on such carriers is bound to vanish. Only a re-mediation of the original documents can prevent precious knowledge from being permanently lost. In particular, ethnic music audio documents are often recorded on non-professional carriers by means of amateur recording system, or, more in general, in fieldwork circumstances. Thus, the preservation of the carrier and the restoration of the audio signal are crucial to avoid the permanent loss of the musical heritage, which is already heavily corrupted. This article describes the protocols defined, the processes undertaken, the results ascertained from several audio documents preservation/restoration projects carried out in the ethnic music field, and the techniques used. In particular: (i) a number of recommendations are given for the re-recording process, and (ii) an audio restoration environment (constituted by three audio restoration tools), developed using the VST plug-in architecture and optimized for different audio carriers (cylinders, shellac discs, tapes) is detailed. The experimental results and the perceptual assessment presented show the effectiveness of the restoration environment developed by the author.