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Program National Recording Preservation Plan

Guide to Vintage Audio Formats

The Visual Guide to Audio Formats indentifies and describes many of the physical audio formats that have been created since the 1890s. Each entry includes photographs highlighting distinguishing characteristics, general period of use, and terminology associated with the item. This Guide will be updated regularly.

Compact Cassette Tape

Descriptive title The best of Patsy Cline, Volume 2
Format Compact cassette tape
Also known as Sound cassette
Date of specific item Ca. 1993
Format date range 1963-present
Material/Construction 1/8" Magnetic tape (Polyester-based tape with ferromagnetic particles embedded in binder lay-er) attached to take-up reels enclosed in plastic case
Recording characteristics Dolby noise reduction, stereo., quarter track con-figuration
Speed 1 7/8” (1.875) inches per second (ips)

Open Reel Magnetic Tape

Descriptive title Unpublished commercial recording
Format Open reel magnetic tape
Also known as Sound tape reel
Reel-to-reel tape
Date of specific item Ca. 1981
Format date range 1948-1980
Material/Construction 1/4" Magnetic tape (Polyester-based tape with
ferromagnetic particles embedded in binder layer)
wound onto 7" diameter plastic reel with slotted hub
Speed 7 1/2 inches per second (ips)

Analog Disc

Descriptive title Act II, scene ii, Hamlet's Soliloquy / John Barry-more
Format Analog disc, 45 rpm
Also known as sound disc
45 rpm disc
7" vinyl disc
Date of specific item ca. 1950
Format date rage 1949-2000
Material/Construction Red translucent vinyl (PVC) plastic
Recording characteristics Monoaural recording
Speed 45 revolutions per minute (rpm)

Brown Wax Cylinder

Descriptive title Do we want him / John Gaskin (William McKinley campaign song)
Format Brown wax cylinder
Recording characteristics Mono.
Recording speed 120-160 RPM
Also known as Sound cylinder
Dimensions diameter: 2 in. ; height: 4 in.
Date of specific item 1896
Date of development 1888
Date of obsolescence 1902
Material/Construction Metallic soap composite material (wax-like)

Metal Mother mastering disc

Descriptive title Now I ain't got nothin' at all / Pine Top Smith
Format Analog sound disc
Recording characteristics Mono.
Recording speed 78 RPM
Also known as Metal master disc
Metal mother disc
Dimensions diameter: 10 in.
Date of specific item 1929
Date of development 1900
Date of obsolescence ca. 1941
Material/Construction Primarily nickel and copper, constructed via electroplating accretion

Paper-based Magnetic Tape

Descriptive title Unidentified recording, Andrews Sisters Collection
Format Analog sound tape
Recording characteristics Mono.
Recording speed Unknown
Also known as Magnetic paper tape
Dimensions diameter: 7 in. ; thickness: 1/4 in.
Date of specific item ca. 1946
Date of development 1938
Date of obsolescence 1948
Material/Construction Cellulous paper with ferric oxide (Fe2O3) particles adhered with unidentified binder

Vinylite "Unbreakable" Disc

Descriptive title Lucky, lucky, lucky me / Evelyn White
Format Analog sound disc
Recording characteristics unbreakable (78 rpm) disc
Recording speed 78 RPM
Also known as Vinylite disc
Vinyl-acetate disc
unbreakable (78 rpm) disc
Dimensions diameter: 10 in.
Date of specific item 1950
Date of development 1930
Date of obsolescence ca. 1955
Material/Construction Copolymer of vinyl chloride and vinyl acetate

Dictaphone "Dictabelt" recording

Descriptive title Unidentified Dictabelt recording
Format Grooved belt
Recording characteristics Mono.
Recording speed approx. 24 inches per second
Also known as Memobelt recording
Analog belt recording
Flexible sound cylinder
Dimensions diameter: 12 in. ; height: 3.5 in.
Date of specific item ca. 1964
Date of development ca. 1947
Date of obsolescence ca. 1970
Material/Construction Cellulous acetate plastic

Large-spool magnetic wire recording (for Armour Model 50a machine)

Descriptive title Unidentified recording from the Marine Corps Combat Recordings Collection
Format Magnetic wire (large spool)
Recording characteristics Mono.
Recording speed 60 inches per second (30 inches per second also possible)
Also known as Wire recording
Dimensions diameter of reel: 3.75 in. ; height: 1.5 in. ; length of wire: approx. 7200 ft ; diameter of wire: 0.0004 in.
Date of specific item ca.1945
Date of development experiments as early ast 1898
Date of obsolescence 1950
Material/Construction Steel wire (susceptible to corrosion)

Small-spool magnetic wire recording (for Webster-Chicago machines)

Descriptive title Recording from the Don Yoder Collection
Format Magnetic wire (small spool)
Recording characteristics Mono.
Recording speed 24 inches per second
Also known as Wire recording
Dimensions diameter of reel: 2.75 in. ; height: 0.5 in. ; length of wire: approx. 7200 ft. ; diameter of wire: 0.00036 in.
Date of specific item ca. 1945
Date of development experiments as early as 1898
Date of obsolescence 1950
Material/Construction Stainless steel wire

Dictaphone wax cylinder

Descriptive title [Unidentified recording]
Format Recordable soft wax cylinder
Recording characteristics Monophonic, vertical-cut (hill-and-dale) grooves
Recording speed 160 rpm, 150 threads per inch (tpi)
Also known as Not to be confused with the Ediphone cylinder, which was not compatible with
Dimensions Length: 8 in., diameter: 2.25 in.
Date of specific item Ca. 1930s
Date of development 1890
Date of obsolescence 1945
Material/Construction “wax” was actually metal soaps and stearic acid

Gray Audograph, instantaneous disc

Descriptive title Gray Audograph
Format Instantaneous grooved disc recording
Recording characteristics Groove embossed into soft plastic disc by a recording device. Discs were only compatible with Audograph recorders. Sound was recorded from the inside of the disc to the outside.
Recording speed Variable: to maximize recording time, the disc speed decreased as the stylus moved to the outside of the disc
Also known as Similar to Soundscriber discs (not compatible) or flexi-discs (not compatible)
Dimensions 5.75 in. diameter
Date of specific item Ca. 1945
Date of development 1945-1950
Date of obsolescence 1950
Material/Construction Soft polyvinyl chloride (PVC) plastic
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