A Summary of a Report Published by the Council on Library and Information Resources and Library of Congress

Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Transferring Analog Discs and Tapes

March 2006
This summary was written by Kathlin Smith

In January 2004, the Library of Congress hosted a roundtable meeting of audio experts to discuss the best practices for transferring analog discs and tapes of historical value to digital formats. Most old recordings are at risk of disappearing or of becoming inaccessible within a few generations because the playback equipment will have become obsolete. It is thus important to reformat historical recordings to current technologies while the older formats are still playable.

This report summarizes what roundtable experts believe to be the best procedures for transferring analog audio tapes and discs to digital output. It includes a series of broad recommendations for improving the practice of analog audio transfer for preservation. The report is aimed at anyone who is professionally entrusted with an audio collection-for example, library directors, preservation managers, sound archivists, and audio engineers.

Discussions of Best Practices

Roundtable discussion focused on such issues as mitigating deterioration of the original sound recording, obtaining the most accurate transfer possible, best practices for digital conversion, sampling standards, manual versus automated transfer, and creating metadata for digital recordings. Discussions revealed agreement on most practices but also highlighted areas of disagreement that will benefit from further research. For example, while participants agreed that stylus choice is one of the most important factors in transferring audio from disc, they disagreed as to whether a stylus could be selected on a purely scientific basis or whether expert listening should also inform the choice. Such areas of agreement and lack of consensus are summarized in a workflow document presented in part two of the report. The document covers pretransfer, transfer, and post-transfer quality control steps for both audio tapes and audio discs.

Broad Recommendations for Preservation

Toward the end of the discussions, participants made a series of broad recommendations for improving the practice of analog audio transfer for preservation. They then ranked the recommendations in order of priority. The 15 top priorities were as follows:

  1. Develop core competencies in audio preservation engineering. Participants noted with concern that the number of experts qualified to transfer older recordings is shrinking and emphasized the need to find a way to ensure that the technical knowledge of these experts can be passed on.
  2. Develop arrangements among smaller institutions that allow for cooperative buying of esoteric materials and supplies.
  3. Pursue a research agenda for magnetic-tape problems that focuses on a less destructive solution for hydrolysis than baking, relubrication of acetate tapes, and curing of cupping.
  4. Develop guidelines for the use of automated transfer of analog audio to digital preservation copies.
  5. Develop a Web-based clearinghouse for sharing information on how archives can develop digital preservation transfer programs.
  6. Do further research into nondestructive playback of broken audio discs.
  7. Develop a flowchart for identifying the composition of various types of audio discs and tapes.
  8. Develop a reference chart of problematic media issues.
  9. Collate relevant audio engineering standards from organizations.
  10. Research safe and effective methods for cleaning analog tapes and discs.
  11. Develop a list of music experts who could be consulted for advice on transfer of specific types of musical content (e.g., determining the proper key so that correct playback speed can be established).
  12. Research the life expectancy of various audio formats.
  13. Establish regional digital audio repositories.
  14. Cooperate to develop a common vocabulary within the field of audio preservation.
  15. Investigate the transfer of technology from such fields as chemistry and materials science to various problems in audio preservation.

Conclusion

At present, there are both audio engineers and equipment capable of safely transferring even the oldest analog recordings to digital format. This situation, however, will not last for long. If key technical knowledge is not passed on soon, thousands of recordings of great historic value may not be accessible to the next generation of listeners. Roundtable members agreed that sharing their expertise with colleagues in audio archiving and audio engineering, both now and in the future, is essential. Some leading associations in the audio field have already launched unilateral efforts that may lead to progress in developing standards for digital preservation. Participants agreed that more communication among these groups should be encouraged to facilitate the sharing of information and recommendations.


More About this Report

Capturing Analog Sound for Digital Preservation: Report of a Roundtable Discussion of Best Practices for Transferring Analog Discs and Tapes
March 2006. ISBN 1-932326-25-1. 37 pages.

Commissioned for and sponsored by the National Recording Preservation Board, Library of Congress. Copublished by CLIR and the Library of Congress. The text of the report is available free on CLIR’s Web site at https://www.clir.org/pubs/abstract/pub137. Print copies can be ordered at this URL for $20 per copy plus shipping.