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

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Commissioned for and sponsored by the National Recording Preservation Board, Library of Congress

March 2006

Copublished by the Council on Library and Information Resources and the Library of Congress.

Copyright 2006 in compilation by the Council on Library and Information Resources and the Library of Congress. No part of this publication may be reproduced or transcribed in any form without permission of the publishers. Requests for reproduction or other uses or questions pertaining to permissions should be submitted in writing to the Director of Communications at the Council on Library and Information Resources.

The National Recording Preservation Board
The National Recording Preservation Board was established at the Library of Congress by the National Recording Preservation Act of 2000. Among the provisions of the law are a directive to the Board to study and report on the state of sound recording preservation in the United States. More information about the National Recording Preservation Board can be found at



Part One


The Preservation Challenge:
Changing Technologies for Recorded Sound
Addressing the Challenge of Preserving Our Audio Heritage
Summary of Meeting Discussions

Mitigating Deterioration of the Original Analog Carrier
Obtaining an Accurate Transfer
Best Practices for Digital Conversion/Considering a Sampling Standard
The Human Touch versus Automated Transfer
Creating Metadata

Part Two

Recommended Procedures for Transferring Analog Audio Tape and Analog Audio Disc for Digital Output, with Participant Commentary

Appendix 1. Suggested Road Map for Best Practices Document for Analog-to-Digital Conversion

Appendix 2. Meeting Participants


For more than 115 years audio recordings have documented our culture and enabled us to share artistic expressions and entertainment. Among all the media employed to record human creativity, sound recordings have undergone particularly radical changes in the last 25 years. The “digital revolution” has introduced new audio formats to consumers and library collections. Institutional archives are now making a transition from preserving audio collections on tape reels to creating digital files. Libraries and archives face both opportunities and challenges. New distribution systems have provided archives with a broader universe from which to acquire collections, but, at the same time, new formats have created new demands on our preservation resources.

In the National Recording Preservation Act of 2000, the U.S. Congress recognized the significance of sound recordings in our lives and the need to sustain them for future generations. That law created in the Library of Congress the National Recording Registry of historically, culturally, and aesthetically significant recordings; the National Recording Preservation Foundation; and the National Recording Preservation Board, a body of recording industry and library professionals who advise the Library of Congress on preservation issues.

Congress’s commitment to assuring the future of professional audio preservation was further demonstrated in the law’s directive to the Recording Board to conduct a study of “the current state of sound recording archiving, preservation and restoration activities.” The study was to include, according to the legislation, an examination of “the establishment of clear standards for copying old sound recordings.” This publication, the third in the series for the preservation study and the first to address technical issues relating to audio preservation, provides some useful indicators of progress in audio preservation standards by reviewing current practices in copying analog discs and tapes.

While libraries develop ways to maintain and serve their digital collections, they still face challenges in maintaining audio collections in older formats. Analog discs and tapes continue to require attention and pose particular challenges. For historical audio recordings to be accessible to researchers in the future, specialized equipment must be maintained for playback. Many of these analog recordings are deteriorating and must be reformatted while they are still playable.

Authoritative manuals on how to create preservation copies of analog audio recordings do not yet exist. There are, however, many highly skilled preservation engineers working throughout the United States. To begin to fulfill the Congressional mandate to establish standards for audio preservation, the Library hosted a roundtable discussion in 2004 and invited some of these talented engineers to share their methods for copying recordings. The roundtable revealed agreement on most practices and on a number of areas in which further research is needed. I am extremely grateful to these professionals for donating their time and sharing their expertise. As this report indicates, much more work remains if we are to preserve the knowledge and expertise of these individuals in order to inform preservation professionals in the future. The National Recording Preservation Board is committed to documenting best practices for sustenance of our audio heritage and sharing that work with the preservation community.

James H. Billington
Librarian of Congress


The ability to record and play back the sounds that surround us-human voices, musical performances, the sounds of nature-has existed for little more than 125 years. Yet the body of recorded sound that has been produced since its inception in 1877 already constitutes one of the greatest creative, historical, and scientific legacies of the United States. Given the importance of recorded sound to our economic well-being, cultural enrichment, and ability to stay informed by means of radio, television, and the World Wide Web, it is alarming to realize that nearly all recorded sound is in peril of disappearing or becoming inaccessible within a few generations.

Our audio heritage is fragile because it depends on technologies and media that are constantly improving and are thus constantly replaced and unsupported by newer generations of hardware and software. Our continued ability to hear recorded sound will depend, first and foremost, on technologies that capture audio signal on obsolete formats-such as wire recordings, cylinders, instantaneous lacquer discs-and migrate or reformat them onto current technologies. To ensure that the recorded sounds of the past century are available for study and pleasure by future generations, we must not only preserve the media on which they were recorded but also guarantee that we have the hardware to play back the recordings, an understanding of the media, and the expertise to extract the best-possible sounds from antique recordings of all types. That said, the formidable technical challenges are merely the proximate cause of the fragility of these recordings. The ultimate challenge to providing access now and in the future is political and organizational: As a society, we must find the will and the resources to define this problem as a priority and to address the problems that technology poses.

Recognizing the importance of our audio heritage to the nation, the U.S. Congress created the National Recording Preservation Board (NRPB) in the National Recording Preservation Act of 2000. Operating under the aegis of the Library of Congress (LC), the NRPB is leading a national effort to address the preservation of and access to the recorded sound held by libraries, archives, historical societies, studio vaults, and private collectors as well as by others who create, care for, and care about audio. In the legislation that created the NRPB, Congress directed the Board and the Library to report on the current state of recorded sound preservation and to develop a national plan to preserve and broaden access to recorded sound. The Library asked the Council on Library and Information Resources (CLIR) to commission background investigations and to convene experts to inform their study. This publication is the third of a series that has been produced in response to the LC’s request. The first two publications reported on the accessibility of out-of-print recordings and copyright of recorded sound.*

This report is the first of two documents that will investigate procedures to reformat sound on analog carriers to digital media or files. It summarizes discussions and recommendations emerging from a meeting of leading audio preservation engineers held January 29–30, 2004, to assess the present state of standards and best practices for capturing sound from analog discs and tapes. A companion report, dealing with key aspects of digital technologies, including file formats and standards, metadata, storage media, repositories, software tools, and collaboration between the archival and scientific community, will be published later this year.

The meeting summary, presented in part one of this report, was written by music writer and historian Paul Kingsbury. Prior to the meeting, Larry Appelbaum and Peter Alyea of the Library of Congress prepared a step-by-step description of practices for transferring two source materials-analog audio tape and analog audio disc-to digital for the purpose of preservation reformatting. These workflow documents were edited and distributed to participants before the meeting and served as the focus of in-depth discussions of preferred reformatting practices at the meeting. Annotations were made to the documents as a result of these discussions, and the revised drafts were then sent back to participants for further comment and annotation through a listserv. That online discussion was closed April 1, 2004. The resulting document is presented in part two of this report.

Much may be learned from the collective expertise of the roundtable members, many of whom are the country’s most respected audio preservation engineers. Documented here are some of the techniques that have been developed to transfer deteriorating sound recordings, and the tools used. The discussions reveal the many times these engineers agree on approaches to obtain the best possible audio transfer from historical recordings, and the occasional instances in which they disagree. The report is not intended to be a handbook on audio preservation engineering. Rather, it is an important component of the study of the current state of audio preservation that Congress requested of the National Recording Preservation Board: a survey of achievements, concurrence, divergence, and needs for further research.

The meeting was devoted nearly exclusively to a discussion of signal-capture techniques. The NRPB sponsored a subsequent round of discussions on March 10–11, 2006; the topic at these sessions was digital file standards and metadata schema. In preparation for those discussions, recording engineer and producer George Massenburg prepared a set of proposed standards for digital file creation; it is provided in Appendix 1.

Responsibility for ensuring long-term access to the recorded-sound heritage of this nation rests with many communities and organizations, public and private, technical and legal, scholarly and popular-indeed, with all who care about recorded sound. LC and the NRPB hope that this report and others that follow will enable those involved to work from a common pool of knowledge and expertise toward solutions that will benefit all.

Abby Smith, Consultant
Council on Library and Information Resources

Samuel Brylawski, Consultant
National Recording Preservation Board
Library of Congress

* Survey of Reissues of U. S. Recordings, by Tim Brooks (August 2005) and Copyright Issues Relevant to Digital Preservation and Dissemination of Pre-1972 Commercial Sound Recordings by Libraries and Archives, by June M. Besek (December 2005).

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