Sound recordings are often present in collections, whether in a library records center, or archival repository. Recordings come in many shapes and sizes, and require a mind-boggling array of playback equipment. In addition, unless the container, cassette, or spool includes identifying information about content and date, the intellectual contents remain a mystery until played back on the appropriate equipment.
There are two basic methods for recording sound: cutting grooves in a surface consisting of metal, wax, glass, or vinyl; or encoding the modulated sounds or wavelengths on wire, paper, and today, magnetic tape. Analogue recording devices and playback machines are media specific, reproducing captured sounds in an analog fashion in a continuous, wavelike fashion. Digital audio capture and playback equipment capture bits and bytes and require computer programs to emulate the recorded sounds. We will focus on the analog formats most common in cultural institutions.
Wax and Tin
Mechanical equipment to record sound was invented by Edison in 1877 using a tinfoil phonograph. It shouldn’t come as a surprise that recording sound was an offshoot of both the telegraph and the telephone. Edison and his assistants worked together to capture sound by “converting speech to electromagnetic waves” and using tin then wax as a recording medium. It doesn’t take long for an entire industry to evolve around wax cylinder recordings of plays, music, and even dictation and speeches.
By 1881, German inventor Emile Berliner, Alexander Graham Bell, and others invented the phonograph disk or what we know today as an LP. These flat disks captured sound in grooves using a stylus. Sounds were played back, amplified by speakers.
Tape and Cassettes
Magnetic and paper tapes are invented in the 1930s and 1940s and are the fore-runners of analog reel-to-reel and cassettes. Cassettes exist in a variety of formats including 8-track. Magnetic tape was used to encode sound waves and playback equipment transmitted the sound to listeners.
The advent of computers was the death-knell of cassettes, which were slowly phased out to be replaced by Compact Discs (CDs) and other digital formats. Portable digital playback devices, primarily MP3 players and APPs have taken over the playback industry.
The variety of sound formats and media found in archives, historical societies, museums, and record centers is dependent upon the contents and collecting scope of your institution. The most common formats found today are phonograph disks and magnetic tape and cassettes.
Wax Cylinders to Phonograph disks are traditionally composed of three layers. The inside layer is the base which can be metal, glass, cardboard, shellac, or various plastics. The recording layer is etched or cut with a stylus and contains the intellectual content, be it music, spoken word, or both. There’s usually a protective layer although the record or disk may consist of just two layers, base and recording. Phonograph disks were designed or cut to play back at 78, 45, 33⅓ revolutions per minute (rpm).
Magnetic tape also has three layers: a stable base of acetate or polyester, an emulsion layer which holds the recorded information, and a binder layer connecting the base to the emulsion.
Phonograph records were made in a variety of sizes from 6” 45s to 20” transcription (or instantaneous recording) disks. The variety of size and composition of the records can be most problematic for cultural institutions as the need for shelving and storage.
Wax cylinders should be stored on end in their protective sleeves. Records should be stored upright and well supported to prevent damage to grooves and warping of the base. Sleeves and liner notes should be stored with or on the records to prevent loss of intellectual content. Records can be quite heavy when stored in boxes. Care should be taken to identify heavy boxes and to store close to the ground.
Cassettes and magnetic media should also be stored upright in their cases and boxes to prevent damage to the edges of the tapes.
Avoid storage where there is a chance of the records getting wet although they can be dried and cleaned easily following preservation standards.
Store all audio recordings in areas with minimally fluctuating temperature and relative humidity. Standard temperatures of 68-72 degrees Fahrenheit with a relative humidity of 35-55% is best. Store wax cylinders in the same environmental conditions with attention to the relative humidity.
All audio recordings, but most particularly wax cylinders and phonograph disks, can grow mold on their surfaces which, if left unchecked, will eat away at the grooves. Contact a preservation / conservation specialist in audio recordings if mold is present.
Audio playback equipment is as varied and diverse as audio formats in our cultural institutions. Each format requires a different piece of hardware to listen to the recording. Small institutions often reject donations of audio materials because they lack playback equipment, appropriate storage conditions, and trained staff.
Playing the original increases wear and tear to the medium, so many institutions will embark on preservation and reformatting or re-recording projects, transferring analog to digital files for ease of access. Links to the digital files should be added to catalog records and databases for ease of access.
Keep physical playback equipment in good working order, with routine cleanings and maintenance. Cleaning is imperative before and after playing back the physical audio recordings and disks. Better yet, hire a reputable audio transfer company to make preservation quality files for long term storage and for digital streaming. Contact the Association for Recorded Sound Collections (ARSC) http://www.arsc-audio.org/index.php with queries about audio formats and playback equipment.
Summing it up
Audio recordings are just one of the obsolete technologies found in libraries, record centers and archives. These recordings come in a diverse range of formats and on numerous media. All are vulnerable to wear and tear from frequent play, poor storage conditions, and poorly maintained playback equipment. It is important to pair audio recordings with the appropriate playback equipment, while minimizing the frequency of use by transfer to a digital file.
Store like formats together and use the catalog to co-locate audio recordings with the collections. Retain and store any and all intellectual and information materials with the physical recordings when possible while utilizing subject headings and natural language tags to increase visibility of the fragile items.
Audio recordings have a rich heritage and contain the aural heritage of our many cultures. Skills for special librarians include attention to care, handling, and storage as well as providing stable environmental conditions that ensure the longevity of these priceless objects within our collections.
DeGraff, Leonard. Edison and the Rise of Innovation. NY: Sterling Signature, 2013. EMI Archive Trust. “History of recorded music timeline.” https://www.emiarchivetrust.org/about/history-of-recording/
Library of Congress. National Recording Preservation. Tools & Resources “Timeline” History of Recorded Sound Plan.” https://www.loc.gov/programs/national-recording-preservation-plan/tools-and-resources/history/timeline/
Patton, Christopher Ann. “Preservation Re-Recording of Audio Recordings in Archives: Problems, Priorities, Technologies, and Recommendations.” American Archivist 61 (Spring 1998): 188-219.
“Sound Recording and Replication” Wikipedia [accessed 29 July 2019] https://en.wikipedia.org/wiki/Sound_recording_and_reproduction
My next post about “Obsolete Technologies” will focus on Moving Images.
Miriam B. Kahn, MLS, PhD provides education and consulting for libraries, archives, corporations, and individuals. See Miriam’s pieces for Lucidea covering library technology and skills for special librarians. Also check out SydneyEnterprise, and GeniePlus, Lucidea’s powerful integrated library systems.
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