US1753137A - Electrostatic loud-speaker - Google Patents

Electrostatic loud-speaker Download PDF

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Publication number
US1753137A
US1753137A US211544A US21154427A US1753137A US 1753137 A US1753137 A US 1753137A US 211544 A US211544 A US 211544A US 21154427 A US21154427 A US 21154427A US 1753137 A US1753137 A US 1753137A
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United States
Prior art keywords
prism
vibrating
diaphragm
fixed
coverings
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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US211544A
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English (en)
Inventor
Seibt Georg
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Individual
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Individual
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Publication date
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Publication of US1753137A publication Critical patent/US1753137A/en
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers

Definitions

  • This invention relates to a loud speaker operating on the electrostatic principle. Its main characteristic consists in the fact that those surfaces or surface elements which are 5 set in oscillation by the 'electromechanical forces, and which emit the sound into the surrounding space, are arranged in a manner which is particularly advantageous for the radiation of sound.
  • the arrangement is such that the propa ation of sound can take place in as many di erent directions as may be desired.
  • This is attained by constructing the xed electrode in the form of a 15 prism, the outer faces of which are wholly or partly covered by the vibrating coverings.
  • the prism is preferably made hollow an the faces 20 covered by the diaphragm are perforated in a manner known in itself, these perforations reventin an excessive air-cushioning eifect etween t 'e diaphragm and the fixed electrede.
  • the number of sides of the prism may be as large as may be desired. Prisms of hexagonal or quadrilateral shape are advantageous. III
  • the prism may assume the special form of a cube.
  • Figures 1 and 2 show in cross section and in plan respectivel one particularly advant eous form of e invention
  • imite 3 is a plan and Figure 4 a corre- Y sponding sectional elevation of another constructional form of the invention; and l '50 of convenience in manufacture it is owever Figure 5 shows an outer covering of thev o loud advisable to mill, plane or turn channels or grooves in the brass body. If the grooves are planed they will run in the longitudinal direction of the prism. If they are turned they will run circumferentially round the periphery.
  • a suitable diaphragm M of indiarubber, Celluloid or oiled paper is on the outside, if the prism itself is not insulated on the external periphery.
  • a metallic diaphragm of aluminium foil for example can be used, or the layer of aquadag on the Celluloid diaphragm may be turned inwards.
  • the diaphragm is only to bear on the edges of the prism and elsewhere is to be separated by a definite air gap from the metallic body, which may be about 0.03 millimtres at the centre of the sides. In order to secure this air gap, the sides of the polygon are not exactly rectilinear, but are slightly concave in the centre, as shown on an exaggerated scale at a.
  • the diaphragmv is divided into bands or strips which are passed round the periphery of the cylinder and are connected by their ends with one another or with the cylinder.
  • Fig. 2 shows three bands of Celluloid for example, the ends of which are connected with two small metallic pieces m m, which in their turn are screwed together. By turning the screw to a greater or less extent the pull of the band can be adjusted, which is of importance for the..purpose of bringing out: the utmost sensitivity of the loud speaker.
  • the silk threads may alternatively be replaced by thin copper or aluminium wires insulated with varnish or silk braiding.
  • the two end faces of the prism may also be covered by the vibrating coverings. 'Fo'r the sake of greater clearness this case is not illustrated in Figures 1 and 2.
  • the covering of all the surfaces with diaphragms comes into consideration more particularly when the prism is of quadrilateral cross section and its height is equal to the length of its sides, fhat i s, when the fixed electrode is of cubical form.
  • the prism forming the fixed elect-rode may alternatively consist of a very large number of side faces, and in the limit may even be a cylinder. In the latter case it is not the cylinder surface but the base and top surfaces that are covered with the vibrating diaphragms.
  • Such a constructional form is shown in Figures 3 and 4.
  • Figs. 3 and 4 illustrate one constructlonal example, Fig. 3 being a plan, and Fig. 4 a corresponding sectional elevation.
  • S S are two circular pieces of metal, which are provided with numerous holes of from 1 to 2 millimetres in diameter. The two pieces may be soldered together or otherwise connected together at c.
  • r 1 are rings of insulating material about 5 millimetres wide and 0.05 millimetre thick.
  • M1 M2 are two diaphragms which are lightly stressed at the periphery in a convenient manner.
  • As a material for thel diaphragms indiarubber is suitable, which, on the side remote from the metallic pieces S S is rendered conducting by coating it with graph ite.
  • the intermediate rings 1' 1' may be stuck onto the metallic pieces, and the diaphragms onto therings with adhesive. Since the diaphragms deflect most at the centre, it is advantageous not to turn the metallic pieces S S, exactly plane, but to curve the surfaces slightly, in order that the diaphragms may not bear against them in the centre. Instead of indiarubber, celluloid or some other material which is rendered conducting on one side may be employed for the diaphragm. If metal such as aluminium is used for the diaphragm, it is advisable to varnish the pieces S S on the surface or to coat them with paper, care being taken that the perforations arenot left closed up. Paper readily admits of being subsequently pierced ywith a needle.
  • the metal pieces S S form one coating, and the two diaphragms the other coating of the condenser loud speaker.
  • the arrangement of the electrical connections and the method of operation do not in any way differ from those which are usual 'with A other electrostatic loud speakers.
  • Fig. 5 illustrates an outer covering of the Y cylinder ⁇ loud speaker according to Figs. 1 and 2, and is intended to show the possibility of an artistic design.
  • the fixed counter-electrode might be constructed as an elongated prism of triangular cross section, as indicated in Figs. 9 and 10.
  • Anelectrostatic loud speaker comprising a fixed prism, and vibrating coverings covering the external faces of said fixed prism.
  • An electrostatic loud speaker comprising a fixed hollow prism, said hollow prism being formed with perforations in its faces, and vibrating coverings covering externally the perforated faces o said fixed prism.
  • An electrostatic loud speaker comprising a fixed prism with its faces made somewhat concave, and vibrating coverings covering the external faces of said fixed prism, the vibrating coverings being electrically insulated from the xed prism where they bear upon said fixed prism.
  • An electrostatic loud speaker comprising a fixed prism, and vibrating coverings covering the external faces of said fixed prism, said vibrating coverings being made of insulating material and rendered conductive on their external surfaces.
  • An electrostatic loud speaker comprismeals? a. fixed pri'sm and vibrating coverings covering the external faces of said fixed prism, said vibrating coverings consisting of passed round the peripheral su ace of 't e prism. Y
  • a n electrostatic loud speaker comprising a fixed prism, and vibrating coverings covering the external faces of said fixed prism, said vibrating coverings being made of insulating material and rendered conductive on their external surfaces, and said insulating coverings being in contact with said fixed prism.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
US211544A 1926-08-12 1927-08-08 Electrostatic loud-speaker Expired - Lifetime US1753137A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE1753137X 1926-08-12

Publications (1)

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US1753137A true US1753137A (en) 1930-04-01

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Family Applications (1)

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US211544A Expired - Lifetime US1753137A (en) 1926-08-12 1927-08-08 Electrostatic loud-speaker

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Country Link
US (1) US1753137A (fr)
DE (1) DE523587C (fr)
FR (1) FR640926A (fr)
GB (1) GB275962A (fr)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421820A (en) * 1941-03-07 1947-06-10 Hartford Nat Bank & Trust Co Microphone
US2519810A (en) * 1947-12-05 1950-08-22 Jose W Acosta Electrostatic sound reproducer
US2552878A (en) * 1947-09-24 1951-05-15 Electro Voice Second order differential microphone
US2627558A (en) * 1946-07-22 1953-02-03 Electro Voice Unidirectional microphone
US2824178A (en) * 1954-04-26 1958-02-18 Philco Corp Transducers
US2878323A (en) * 1954-04-26 1959-03-17 Philco Corp Transducers
US3082298A (en) * 1959-03-04 1963-03-19 Akg Akustische Kino Geraete Frequency independent directional condenser microphone
US3146308A (en) * 1959-10-09 1964-08-25 Gorike Rudolf Capacitor microphones
US3978353A (en) * 1974-05-10 1976-08-31 Pioneer Electronic Corporation Piezoelectric acoustic speaker system
US10185054B2 (en) * 2015-11-04 2019-01-22 Quantum Technology Sciences, Inc. System and method for improved seismic acoustic sensor performance

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421820A (en) * 1941-03-07 1947-06-10 Hartford Nat Bank & Trust Co Microphone
US2627558A (en) * 1946-07-22 1953-02-03 Electro Voice Unidirectional microphone
US2552878A (en) * 1947-09-24 1951-05-15 Electro Voice Second order differential microphone
US2519810A (en) * 1947-12-05 1950-08-22 Jose W Acosta Electrostatic sound reproducer
US2824178A (en) * 1954-04-26 1958-02-18 Philco Corp Transducers
US2878323A (en) * 1954-04-26 1959-03-17 Philco Corp Transducers
US3082298A (en) * 1959-03-04 1963-03-19 Akg Akustische Kino Geraete Frequency independent directional condenser microphone
US3146308A (en) * 1959-10-09 1964-08-25 Gorike Rudolf Capacitor microphones
US3978353A (en) * 1974-05-10 1976-08-31 Pioneer Electronic Corporation Piezoelectric acoustic speaker system
US10185054B2 (en) * 2015-11-04 2019-01-22 Quantum Technology Sciences, Inc. System and method for improved seismic acoustic sensor performance

Also Published As

Publication number Publication date
DE523587C (de) 1931-04-28
FR640926A (fr) 1928-07-24
GB275962A (en) 1928-10-25

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