As with digital video, digital audio files have become far easier to create over the last ten years. Although digital video has perhaps found more applications in archaeology, digital audio files are often created as a component of projects looking to record oral histories or to recreate 'archaeological sounds', either through the modern reconstruction of archaeological musical instruments or through the recording of sounds within archaeological contexts such as reconstructed - physically or virtually - churches, henges or theatres. A number of examples of the latter exist in the online Internet Archaeology journal (e.g. Thomas 2011).
As with the Digital Video guide, this guide aims to address the issues involved in the creation and preservation of 'born digital' audio files and will not aim to cover the creation of files from analogue originals (although many of the issues discussed here equally apply). The digitisation of analogue audio files is covered in detail in the JISC Digital Media guide 'Audio: Digitising analogue media' . In addition to the extensive material available on the JISC Digital Media site, this guide also draws heavily from a number of other key guides on preserving digital audio files, namely the AHDS 'Preservation Handbook: Digital Audio' (Knight & McHugh 2005), JISC's 'Significant Properties Testing Report: Audio Recordings' (Knight 2010) and IASA Technical Committee's 'Guidelines on the Production and Preservation of Digital Audio Objects' (2nd ed.) (Bradley 2009). A detailed introduction to the technical aspects of digital audio files can also be found in the JISC Digital Media guide 'An Introduction to Digital Audio'.
Again, as with digital video data, digital audio files may be large when created/stored in uncompressed formats and informed decisions need to be made when deciding when and how lower quality files are created. Another issue that is again similar to digital video is that the range of digital audio files consist of a mix of container fomats and codecs which again emphasise the importance of detailed technical metadata in successfully identifying and working with audio files. Metadata also plays a key role with audio files in documenting the file's creation process and contents (e.g. names and dates of interviews, locations, etc.) as these elements may not be as apparent as in similar video files.