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
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)
