Leave a comment

Adventures in Audio Digitization

In early February 2017, Don Manildi, Curator of the International Piano Archives at Maryland (IPAM), wrote to Eric Cartier:

“IPAM recently received four 15ips (inches per second) 10.5 inch reels from one of our most important donors, pianist Margaret Leng Tan, containing a recital she played in NY back in 1982. She is hoping we can prepare a CD-R copy of the recital for her (and retain one for IPAM, too). Presumably, this could be accomplished most efficiently here in our studio,” thus began a challenging media reformatting request.

Don and Eric agreed to meet in the Performing Arts Audio Digitization Studio (PAADS) in early March 2017, to digitally reformat the magnetic tapes. PAADS had not been in use for many months, so Eric spent most of his initial visit testing playback equipment and monitors, checking software settings, and ensuring the source-to-destination chain was completely connected. Once everything was prepared and the first tape was threaded on the reel deck, however, he discovered it was affected by sticky shed syndrome. Polyester magnetic tape is susceptible to binder hydrolysis, which occurs when a tape collects water particles over time and adheres to itself. If the tape will play and is not permanently stuck, it usually squeals and can damage playback heads, or the recording layer of the tape will fall off when touching the heads, resulting in permanent loss of the sound recording. Having handled and transferred hundreds of open reel tapes in the past, Eric had never encountered tapes as severely sticky as these. Don and Eric conferred and, following standard practice in AV archives, decided to bake the tapes in a scientific oven at 120 degrees Fahrenheit for eight hours, a process commonly used to dry out tapes and render them temporarily playable.

The tapes were still extremely sticky and unplayable and it was not possible to make transfers the following day. Eric added leader to the loose ends of each tape and fast forwarded them as far as possible, then rewound them and took photos of the visible deterioration (popped strands, slipped packs, resin-like ooze) to share with Don, Vin Novara, Curator of the Performing Arts Collection, and Eric’s supervisor, Robin Pike, Manager of Digital Conversion and Media Reformatting. He conducted research about the Scotch 226 tape stock, learning it is so notoriously sticky it almost single-handedly prompted the production of scientific ovens for baking tapes. The lone Memorex tape had no specific stock information, though. In fact, all four tapes lacked containers, which may have contained more descriptive or technical metadata.

Minimal metadata on the Tan Reels

An example of the minimal metadata provided with the Margaret Lang Tan reels.

Don encouraged Eric to write to the Association for Recorded Sound Collections listserv, to crowdsource information about what to do with excessively sticky tapes. The response was swift, and 12 people replied with advice, guidance, and stories. Robin wrote to George Blood, the accomplished audiovisual digitization guru and owner of George Blood Audio Video Film to solicit information to continue the endeavor in-house. The first word in his reply – “Yikes!” – followed by chemistry-based approaches to solve the problem. Eric baked the tapes a second time to see if an additional eight hours would yeild more promising results.

A photo documenting the extremely sticky residue on the tape

Extreme sticky shed syndrome

Eric found the tapes had slightly loosened, but that upon playback, all four eventually began to squeal and stopped playing despite 16 total hours of baking. He noted the exact times at which the tapes stopped, as well as distinctive problems (e.g., the Memorex reel was warped and scraped the length of one side of the flange each time it turned). Eric considered the tapes unrecoverable in-house and Robin worked with our contracted vendor to send the tapes for more involved stabilization and digitization.

GBAVF shared helpful updates via email throughout the process. After storing the tapes in a low humidity vault for a while, they rehoused them, “auditioned” them, discovered the high quality of the recording, cleaned the tapes, and then made expert transfers in late April. In early May, Eric inspected the quality of the digital files and uploaded the MP3s to ShareStream, our streaming media manager; student digitization assistants made double-disc sets for Don and the donor. Bria Parker, Head of Discovery and Metadata Services, prepared the metadata record and Josh Westgard, Systems Libraries, archived the preservation master files, then ingested the metadata and the streaming files to Digital Collections, completing the project. Later this summer, Don listened closely to the entire recording and prepared a detailed track listing, which Josh modified in the XML. After much time, effort, and collaboration, we freed the valuable content from the problematic carriers, described it in great detail, and made it available to the creator and the public.

We are pleased to provide Margaret Leng Tan’s April 1982 recital in its digital form: http://hdl.handle.net/1903.1/39411.

Discuss!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s

%d bloggers like this: