Archival audio preservation

The source is the recording you received: a physical carrier or an existing digital file, together with labels, notes and other context. Record which item it is and where it came from.

The preservation master is the archive's retained reference. For an analogue recording, this usually follows a carefully documented transfer. IASA's preservation principles call for the closest possible surrogate and advise against subjective improvements during that transfer. Necessary replay decisions still require specialist judgment and documentation. State whether the transfer is intended to capture the recorded content or document a historical playback experience. In CCAHA's audio preservation demonstration, the machine and horn contribute to the sound, showing why that choice matters.

A restoration or production version is a separate file used to make listening changes. An access copy can then be created in a format suited to the intended player, website or researcher. An archive may keep additional intermediate versions; names vary, so define the role of each file in your own policy.

The Canadian Heritage Information Network's digitization guide separates its preservation, production and access files. The useful distinction is their purpose, rather than a particular filename prefix.

Make an inventory before treating the collection as one restoration job. Record the item identifier, format, apparent condition, duration if known, available copies and playback requirements. Keep packaging and accompanying information associated with the correct item.

IASA recommends selecting the best available copy before reformatting. Compare provenance and transfer quality as well as physical condition. A clean-looking duplicate may contain a poorer earlier transfer; a familiar filename does not prove that it is the earliest or most complete version.

For existing digital audio files, retain the received file. Converting an MP3 into WAV does not recreate the information already removed by lossy encoding. A preservation plan can retain the original alongside a supported derivative without treating conversion as a quality improvement.

Plan the queue around the collection's policy and actual risks. IASA identifies deterioration and playback obsolescence as important priorities. The CHIN guide also starts with selection and condition assessment rather than processing every item in an arbitrary order.

Separate three decisions:

1. What is at risk? Identify unstable or damaged carriers and formats for which suitable playback is becoming difficult.
2. What is needed? Record the collection value, available duplicates and specific access request.
3. What can be handled safely? Confirm equipment, skills and storage before scheduling transfer.

If a tape is shedding, mouldy, sticking, damaged or squealing, obtain appropriate conservation or transfer advice before further playback. This guide does not provide a cleaning, baking or physical repair recipe. NARA emphasizes that high-quality reformatting needs suitable equipment and specialized knowledge.

Before preservation reformatting, agree the format and recording settings with the archive or transfer specialist. For digitizing analogue audio, CHIN recommends linear PCM in BWF, with WAV also acceptable. Settings should follow the collection's policy and the source; they are not a reason to resample every received digital file.

Keep a record of the carrier, chosen copy, replay and capture equipment, operator, settings, date and known problems. Identify channel assignments and retain the relationship between separate sides or parts. Distinguish the historical recording date from the date a digital file was created.

FADGI's Broadcast WAVE metadata guidance provides fields for the responsible organization, identifiers, descriptions and file creation information. Embedded fields can help a file remain identifiable, but they do not replace the collection record and linked documentation. Check what survives each export.

State the listening goal before choosing effects: an interview passage for a researcher, a programme for public listening, or a performance for an access service. Use a short representative passage to assess whether a treatment helps that goal without removing wanted detail.

Compare the processed copy with the retained reference at a similar listening level. Check speech consonants, quiet voices, musical transients, pauses and background context relevant to the item. Listen for new artifacts as well as reduced noise. Keep unresolved words uncertain; a cleaner-sounding result is not evidence for a guessed quotation.

Record the software and version, processing order, settings and affected passages. If you make cuts, level changes or other editorial alterations, label that derivative accordingly. Keep a route back to the unmodified reference. The restoration version should never silently become the only surviving copy.

Quality control has separate content and file-integrity jobs. CHIN's review checks include matching collection numbers to filenames and audio, checking beginning and ending content, and reviewing technical metadata. Also confirm the intended channels and parts are present before accepting the handoff.

For file integrity, save a checksum when a file enters the managed collection and compare it after copying and during scheduled checks. The Library of Congress explains that whole-file and audio-data checksums can answer different questions: changing embedded metadata can change a whole-file checksum even when the audio data is unchanged.

Record the scope of each check. A checksum match against a trusted earlier value supports byte integrity for that comparison. It cannot establish who originally spoke, whether the recording was edited before receipt, or whether a transfer omitted a side.

Long-term management continues after a file has been created. NARA calls for managed storage, regular checking and backups. Keep preservation copies separately from everyday working files, maintain additional copies according to policy, and verify that a stored copy can be retrieved and played. Assign responsibility for checks and future migration. Digitization is the start of ongoing file care.

Choose tools around the jobs they must support: keep identifiers and processing records connected, validate files, record and compare checksums, create access versions, and keep files retrievable as software changes. The national recording preservation plan's tools chapter distinguishes creation software from later repository management. Choose arrangements the collection can operate and maintain; a software name alone is not a preservation plan.

Choose the access format for the actual use, while retaining the preservation reference. Include the identifier and version relationship, a description of the changes, and any relevant uncertainty. Check transcripts or captions against the recording rather than assuming processing has settled difficult words.

Confirm intellectual property rights, donor restrictions and the permitted audience before publication or external sharing. IASA's ethical guidance treats access agreements and contextual information as part of responsible collection care.

For a restoration review of an existing digital recording, provide a copy and explain the intended use, difficult timestamps and earlier processing. Discuss any transfer or handling restrictions first. If you have physical carriers, arrange a qualified transfer before digital cleanup. Confirm collection-scale preservation and any physical delivery requirements separately.

This guide compares published archival principles with the practical roles of source, preservation, restoration and access files. It draws on IASA, NARA, CHIN, FADGI and Library of Congress guidance. It does not report a restoration experiment, certify a repository, or assess an individual carrier.

Institutional policies differ. IASA recommends retaining physical carriers after transfer wherever possible; CHIN discusses deaccessioning after digitization in a museum context. Follow the collection's approved retention and disposal process. Successful playback of one digital copy is not, by itself, a disposal decision.

A useful restored access copy should remain connected to a retained reference and a clear account of the work. That lets a future listener compare versions, understand the limits and make a different treatment when the research question changes.