The Stephen O. Murray and Keelung Hong Special Collections at Michigan State University Libraries offer a diverse assortment of collections (including Africana, Comic Art, Radicalism, and LGBTQ+, just to name a few), containing over 450,000 printed works, and numerous manuscript and archival collections. The collections also contain audiovisual materials, and my first conservation project outside of the University Archives collections came from the Louis Brenner papers.

“Dauda Maiga, Bandiagara”, September 29, 1977

Louis Brenner (1937-) is Emeritus Professor of the History of Religion in Africa at the School of Oriental and African Studies (SOAS) University of London. During the mid-1970s, Brenner began to research traditional forms of Muslim education and Muslim thought in Mali, which ultimately led to the publication of West African Sufi: the Religious Heritage and Spiritual Search of Cerno Bokar Saalif Taal1.

Research for this book was greatly enhanced by the generous cooperation of Amadou Hampâté Bâ2 (circa 1900-1991), a Malian writer, historian and ethnologist. Over a period of several years, Hampâté Bâ granted Brenner many hours of interviews, in Mali, Paris, and Abidjan (Ivory Coast). Hampâté Bâ is remembered for the saying “whenever an old man dies, it is as though a library were burning down.”3

The audio recordings in the Brenner papers consisted of thirty-two compact cassettes, four ¼” open reel audio tapes, and a flash drive containing mp3 files from one of the cassettes. The recordings date from circa 1966-1988, bulk 1977-1978. The tapes were donated to Special Collections as part of the African Activist Archives Project. The content of the recordings consists of one-on-one interviews with Hampâté Bâ and other individuals, and field recordings of religious ceremonies and dances. Despite the advanced age of the tapes, the quality of most of the recordings was good.

“Maiduguri singer”, undated

An assessment of the collection showed that the tapes were, for the most part, in good condition. The notes on all of the tape cases were handwritten, so some names and subjects written in cursive were difficult to decipher. As best as possible, metadata from the collection was collected and entered into records in the AVCC (Audiovisual Collaborative Cataloging) database. The write-protect tabs at the top of each tape were removed, to avoid accidental erasure of the recorded content.

Digitization of the first cassette went well, but the second tape presented a rather drastic issue: the tape-up reel/spool inside had broken. In order to make the cassette playable again, an intact reel from another unused blank tape was used as a replacement. The little bit of leader tape attached to that reel was spliced to the leader from the original cassette, and after the shell was closed back up, the tape was ready for playback.

The broken take-up reel from cassette 2
The replacement take-up reel, next to the splicing block
Leader from the original tape is spliced together with leader from the replacement take-up reel
Digitization resumes

No other internal damage was present in the remaining cassettes, but three of them were experiencing binder hydrolysis, or “sticky shed syndrome”. This occurs when the oxide or backing from magnetic tape rubs or wears and sheds off onto the various parts of equipment when played back. You may also hear the tape squeal when played back.4

In order to make these three tapes playable again (even if only for a brief window of time), an arrangement was made with the Vincent Voice Library to have the cassettes “baked” in a convection oven at 140°, eight hours a day over a period of four days. This resolved the issue for two of the three tapes, but the third tape was still completely unplayable. However, after opening up the shell of the third tape, a discovery was made: the internal paper sleeve was torn on the top, and the tape had gone through the tear and gotten stuck. The sleeve was replaced with an untorn one (from the same parts as the replacement reel). Problem solved!

The magnetic tape had gotten caught in the tear at the top of this interior paper sleeve

The four open-reel tapes, each on small 3″ reels (see the photo entitled “Maiduguri singer” near the beginning of the blog), presented their own unique challenges. The recordings for these tapes were made at 1 ⅞ ips (inches per second), the same playback speed as with cassette tapes. However, the playback speed options for the open-reel tape decks in the Media Preservation Lab were only 15 ips or 7 ½ ips. Either way, the resulting digitized audio sounded extremely high and fast (think “Alvin and the Chipmunks”).

In order to revert the audio to its original playback speed, a feature in Audacity (the platform used to capture audio digitally) was used to slow the digitized sound by half, then half again, until the resulting playback speed matched the 1 ⅞ ips speed of the original recording. Fortunately, none of the open-reel audio tapes were damaged, or experienced sticky shed syndrome. Unique identifiers containing the collection number, box number, and individual tape number, were written onto each tape (the plastic reels for the open-reel tape required a grease pencil).

After preservation .wav files (96kHz/24-bit) were created for each side of each tape, derivative mezzanine .wav (44.1kHz/16-bit) and access .mp3 (44.1kHz/160kbps) files were made. The preservation files represent digital versions closest to the original analog audio on the tapes; mezzanine files offer a copy that is ready for use in standard production workflows and systems5, such as ripping the audio onto a recordable CD; access files are suitable for online streaming. Finally, md5 checksums were created to ensure file fixity. A checksum on a file is a ‘digital fingerprint’ whereby even the smallest change to the file will cause the checksum to change completely6.

Despite not being able to understand the content of these recordings (all of them sound as if they may be in French, or an iteration of French), I am fascinated by what I have heard on these tapes. I have picked up a copy of Brenner’s book, in order to hopefully gain greater context on the interviews. I have been made aware that a researcher is hoping to use these tapes as part of his dissertation. Future access to the audio on these recordings may be mediated through visiting the Stephen O. Murray and Keelung Hong Special Collections reading room in-person or via the virtual reading room.

  1. (2008). Louis Brenner: Life and Work. World Wisdom.
  2. (2008). Louis Brenner: Life and Work. World Wisdom.
  3. Jolly, M (2013). Encyclopedia of Life Writing: Autobiographical and Biographical Forms. Routledge
  4. National Archives & Records Administration (NARA)(2014). Magnetic Media Audio Condition Assessment. NARA.
  5. Northeast Document Conservation Center (NEDCC)(2018). Fundamentals of AV Preservation. NEDCC.
  6. Digital Preservation Coalition (2015). Digital Preservation Handbook, 2nd Edition, Digital Preservation Coalition © 2015.