About the Format

1/4″ Audio Reel

In the early 1900s, the American Telegraphone Company was the first to make a magnetic wire recorder commercially available—however, the technology proved unpopular, and sat largely unexploited until the late 1930s, when a number of other American corporations, including AT&T and the Bell Telephone Company, took interest in magnetic tape recording. Most of these commercial ventures were sponsored by the United States military. Several, including the Brush Development Company of Cleveland, Ohio, relied on hiring German engineers, such as Semi J. Begun, who had left Nazi Germany in the late 1930s. Begun primarily completed prototypes for several different types of magnetic wire recorders, such as drum recorders that could store images of radar “blips.” 

Telefunken Magnetophon 106
from museum-digital:berlin

Meanwhile, across the Atlantic, magnetic tape recording enjoyed an accelerated development trajectory, particularly in Germany, where German manufacturers in telephone, radio, and phonograph engineering had achieved prominence. The first commercial reel-to-reel recorder, the magnetophon, was developed by engineers at German company AEG in the early 1930s; the blueprints for this technology was later brought over to the United States after World War II. 

Soon after, magnetic tape began to be presented as an alternative to disc recording in film studios—in particular, audio engineers found that the ability to re-record segments on magnetic tape (in comparison to discs, which were impossible to record over in case of blips or mistakes on the first take) was a significant asset.

Joe Haupt from USA, CC BY-SA
2.0 via Wikimedia Commons

Another advantage of open reel audio tape recorders was their potential for portability relative to disc recording setups. This enabled new possibilities for field recordings and for amateurs to create their own sound recordings.  ¼” open reel audio tape was the most common size for amateur recordings, and was the standard width for magnetic audio tape through the 1950s. The use of reel to reel for amateur recordings would not taper off until the 1980s, which saw the increased popularity of cassette tapes. 

Assessing the Format

debris left from
‘sticky shed’ tapes

As with most other magnetic tape formats, ¼” open reel audio tape should have a tight and even tape pack to prevent shrinking and warping. This format is also susceptible to mold, sticky shed syndrome, and acetate deterioration (“vinegar syndrome”). Visit the PSAP (Preservation Self-Assessment Program) Guide for a more complete list of physical assessments and problems commonly associated with ¼” open reel audio tape. 


Unfortunately, all magnetic tape is extremely prone to rapid degradation, and tapes on thinner widths (such as ¼” open reel audio tape) even more so—data on ¼” open reel audio should be migrated to a more stable format as soon as possible, depending on the importance of the content and the constraints of one’s budget. Ideally, if audio tape reels are not already housed in light-proof, acid-free enclosures and stored vertically, they should be rehoused and reoriented.

We bake at 140º F/60º C
for 12+ hours

At the Vincent Voice Library, one of the main issues facing 1/4″ open reel audio tape collections is sticky shed syndrome, and the primary treatment for this is to bake tapes at 140º F/60º C for at least 12 hours in a laboratory convection oven. For further information about this process—how and why it works—please see this article over at Ars Technica.

Additionally, many tapes at the VVL are notable for being “banded” together—meaning that sections of multiple separate recordings have been spliced together onto the same reel, with short bands of white leader tape distinguishing each piece. Frequently, the seams between each segment will need to be re-spliced.


1/4″ Reel Workstation at
Vincent Voice Library Studio

Reel to reel magnetic tape players and recorders are no longer manufactured, and so are becoming increasingly scarce. Playback machines can typically be found at colleges and universities, surplus stores, and television and radio stations—these can be excellent sources of equipment. Equipment must always be tested before use, ideally with a “dummy” or “throwaway” item. See the PSAP (Preservation Self-Assessment Program) Guide’s section on Magnetic Audio Playback for further information. 

Otari MX5050 tape decks are used for playback at the Vincent Voice Library and University Archives; for further information about the Otari MX5050 series, click here.


Always store vertically

¼” open reel audio tape must be stored vertically; when stored horizontally, the tape is prone to warping. Warping is worsened when tapes are stacked on top of one another, as the weight from the other tapes adds pressure and stress. Tapes should ideally be placed in individual acid-free enclosures, with some sort of support for the central hub. These should then be placed in archival boxes. The storage facility should be kept at 40-50º F/4.5-12º C, with 30-50% RH . Use archival hold-down tape to secure the loose ends of the open reel tape. 

Our Collection

Wax Cylinder

In the 1960s-1970s, open reel audio audio tape was considered a preservation format by most archival institutions; as such, the Vincent Voice Library (VVL) has a large collection of open reel audio tapes containing recordings originating from earlier data carriers such as wax cylinders. The VVL has retained the ¼”audio tapes, but the original wax cylinders were, unfortunately, discarded and lost from our collections. Because ¼” open reel tape is currently considered an at-risk format, these tapes, too, will need to be migrated to newer and more stable digital formats. This anecdote illustrates that data migration is an ongoing process: as newer, more stable formats are introduced, data must continually be evaluated and transferred as needed. Migration is not a “once and done” solution. 

Vincent Voice Library

Additionally, the story of ¼” open reel audio tapes at the VVL demonstrates the shifting values of archival practice over time: in this current moment, many archivists would advocate retaining and preserving the original data carrier as long as possible, as time, space, and budgetary constraints allow, maintaining that the original carrier provides a potentially rich source of contextual information about the content it contains, and is a valuable archival object in its own right. 

University Archives (UA) has a substantial collection of ¼” open reel audio tapes as well. Because the UA is primarily focused on Michigan State University history, the bulk of these tapes consist of commencement speeches and recordings from public lecture series, such as the “Great Issues” series and the 1969 Sexuality Colloquy. Additionally, a number of MSU band and recital recordings can be found in the Leonard Falcone Papers

In our highlights reel, we have included a snippet of the following digitized 1/4″ open reel audio tape embedded below, “Protest in East Lansing After ‘Chicago Seven’ Verdict.” From the host “On the Banks” site: “WKAR Program Manager Steve Meuche records his own narrative and audio of rioting in the streets of East Lansing after the February 18, 1970 jury verdict in the ‘Chicago Seven’ court case.” The clip demonstrates the tremendous portability of open reel audio recording equipment by the 1970s, making it an appealing medium to document both activist activity and police violence “on the ground,” in situ.

Protest in East Lansing After “Chicago Seven” Verdict, 1970


“About Reel-to-Reel Tapes and the Bentley’s digitization process.” Bentley Historical Library – University of Michigan, https://deepblue.lib.umich.edu/bitstream/handle/2027.42/108126/ReelDescription.pdf?sequence=1&isAllowed=y

“Audiotape.” Collection ID Guide, Preservation Self-Assessment Program, University of Illinois at Urbana-Champaign. https://psap.library.illinois.edu/collection-id-guide/audiotape

Morton Jr., David. L. Sound Recording: The Life Story of a Technology. The Johns Hopkins University Press, 2004.

“Open Reel Audio.” Advanced Help, Preservation Self-Assessment Program, University of Illinois at Urbana-Champaign, https://psap.library.illinois.edu/advanced-help/av-audioopenreel.

Ouellette, Jennifer. “Here’s why ‘baking’ damaged reel-to-reel tapes renders them playable again.” Ars Technica. https://arstechnica.com/science/2020/04/the-chemistry-of-why-baking-degraded-reel-to-reel-tapes-can-reverse-damage/

“Otari MX5050 series – Summary.” ReeltoReelTech.com: Everything Reel-to-Reel. https://reeltoreeltech.com/otari-mx5050-series/

Schmidt, H.S. Chasing Sound: Technology, culture, and the art of studio recording from Edison to the L.P. The Johns Hopkins University Press, 2013.

Vernon, Mark. “Tape Recording Clubs.” Meagre Resource Productions, http://meagreresource.com/other-projects/tape-recording-clubs/

Werth, Christopher. “The Long, Slow Vanish of Britain’s Illustrious Recording Clubs.” NPR (National Public Radio), https://www.npr.org/2014/07/03/328209574/the-long-slow-vanish-of-britains-illustrious-recording-clubs