microphone
Dateca.1920-1940
Inventory NumberWJ0602
ClassificationMicrophone
Subject
Maker
Universal Microphone Company
ca. 1925 - 1945
Cultural Region
Place of Origin
Place of Use
Dimensions7.6 × 7.4 × 5.1 cm (3 × 2 15/16 × 2 in.)
Material
DescriptionCircular container with grate on one side, held together by six slotted-head screws.
The front of the microphone has a central circular grate with a square grid, ringed by two concentric circles. The outer circle is punctuated by six evenly-spaced bolts. Running through the front cover is a bone-shaped piece of metal with a circular opening in the middle that appears to house a brass circle. The ends of the piece are each fastened to the container with two red screws. A black material separates the piece from the container. A silver screw is fastened into the right end of the piece, the only asymmetrical part of the piece. Atop the central circle is another red screw.
Along the side of the device are four evenly spaced rings whose sides are welded onto the container.
The back of the container has an outer ring, around which are spaced six holes into which the ends of the bolts. Every other bolt end is painted black. Also in this circle is the head of a seventh bolt halfway between the top two bolts. Within this outer circle is a circle consisting of a series of concentric ridges similar to those found on top of a can. On the very center are two cylinders stacked on top of one another. The face of the top cylinder has a hole in it, through which one can see a brass circle. The edge of the face has a single screw, while the side of the cylinder contains two screws.
The front of the microphone has a central circular grate with a square grid, ringed by two concentric circles. The outer circle is punctuated by six evenly-spaced bolts. Running through the front cover is a bone-shaped piece of metal with a circular opening in the middle that appears to house a brass circle. The ends of the piece are each fastened to the container with two red screws. A black material separates the piece from the container. A silver screw is fastened into the right end of the piece, the only asymmetrical part of the piece. Atop the central circle is another red screw.
Along the side of the device are four evenly spaced rings whose sides are welded onto the container.
The back of the container has an outer ring, around which are spaced six holes into which the ends of the bolts. Every other bolt end is painted black. Also in this circle is the head of a seventh bolt halfway between the top two bolts. Within this outer circle is a circle consisting of a series of concentric ridges similar to those found on top of a can. On the very center are two cylinders stacked on top of one another. The face of the top cylinder has a hole in it, through which one can see a brass circle. The edge of the face has a single screw, while the side of the cylinder contains two screws.
Signedon nameplate on side: UNIVERSAL / MICROPHONE / INGLEWOOD, CALIF. / PATENTS PENDING
Inscribedon front: B B / 4373
Curatorial RemarksHad white tag with inventory no. WJ245 but a kymograph already had that no., so changed to WJ0602.
FunctionAccording to Professor Tom Perera of Montclair State University, whose microphone collection is available here, the model BB was a double-button carbon microphone from the 1920s and 1930s. According to an Army manual on microphones, available here., the double-button carbon microphone consisted of a diaphragm that vibrated between two loosely-packed piles of carbon granules held in insulated cups called buttons. When the pressure on the carbon pile changed, the resistance of the pile, and consequently the circuit running through it, would vary according to the vibrations of the diaphragm.
ProvenanceDepartment of Psychology, Harvard University. Moved from William James Hall 6/24/97.
American
Date: 1900-1950
Accessories: clamp; screws (4); wingnut (1); washers (6); nuts (3)
Object number: 1996-1-0266
American
Date: 1900-1950
Accessories: clamp; screws (4); wingnut (1); washers (6); nuts (3)
Object number: 1996-1-0267
George Erle Beggs
Date: early 20th-mid 20th Century
Accessories: 6 deformeter gauges;
22 plugs;
2 cylindrical plastic boxes containing screws and metal strips for fastening the ends of the structure;
metal stylus;
2 metal pins;
2 celluloid wedges;
1 rectangular celluloid piece with a wedge coming out of one end
Object number: 1999-1-0064
F. F. Metzger
Date: circa 1927
Accessories: wooden box lined with velvet cushioning;
strain gauge;
iron bar;
steel rod contact points (2);
nails (3) wrapped in paper;
manual;
single stationery paper;
pamphlet (price list)
Object number: 1999-1-0065
Thomas Hall
Date: circa 1890
Accessories: pulley rope
Object number: 1997-1-1423
International Business Machines Corporation
Date: 1939-1944
Object number: 1997-1-0234
English
Date: circa 1800
Accessories: Two insulated charge transfer wands.
Object number: 0014