GB881584A - Improvements in or relating to electro-acoustic transducers - Google Patents

Improvements in or relating to electro-acoustic transducers

Info

Publication number
GB881584A
GB881584A GB3878758A GB3878758A GB881584A GB 881584 A GB881584 A GB 881584A GB 3878758 A GB3878758 A GB 3878758A GB 3878758 A GB3878758 A GB 3878758A GB 881584 A GB881584 A GB 881584A
Authority
GB
United Kingdom
Prior art keywords
diaphragm
porous
adhesive
bonded
metal
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
Application number
GB3878758A
Inventor
William Donald Cragg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
STC PLC
Original Assignee
Standard Telephone and Cables PLC
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to GB2138257A priority Critical patent/GB832276A/en
Application filed by Standard Telephone and Cables PLC filed Critical Standard Telephone and Cables PLC
Priority to GB3878758A priority patent/GB881584A/en
Publication of GB881584A publication Critical patent/GB881584A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R1/00—Details of transducers, loudspeakers or microphones
    • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
    • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
    • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
    • H04R1/38—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone
    • 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
    • H04R19/01—Electrostatic transducers characterised by the use of electrets

Abstract

881,584. Capacitor microphones. STANDARD TELEPHONES & CABLES Ltd. Nov. 27, 1959 [Dec. 2, 1958], No. 38787/58. Addition to 832,276. Class 40 (4). A pressure-gradient capacitor microphone has a diaphragm open to incident sound on both sides but one of the sides being shielded by a rigid porous member of bonded insulating particles. As shown, in Fig. 4, a metal casing 1 with a perforated back wall 7 encloses a porous member 3. A plastic diaphragm 2 covers the front of the casing over which it is stretched and fixed by adhesive 8. Sputtered gold and sprayed colloidal graphite, respectively, coat the top surface of the member 3 and the outer surface of the diaphragm 2. The coating of sputtered gold is porous. Additional acoustic resistance may be provided by a silk layer 6 covering the back wall 7. As shown in Fig. 1, a diaphragm 10 of polyester, polypropylene, or polycarbonate film is trapped between metal rings 11 and 12 and fixed with adhesive. The rings may be injection-moulded on to the wall of the diaphragm which is formed into a cup-shape and held in the moulding tool. The outer surface of diaphragm 10, and the top surface of porous member 13, is coated with metal or graphite. A spacing washer 14 takes thrust from the member 13 to tension the diaphragm. The microphones may be round or rectangular and may be as much as ten feet long to make a line microphone. The porous members 3 or 13 may be composed of sintered ceramic secured in position by adhesive 9 or 20. Powdered glass, sand or ceramic may be used and be bonded with an epoxy resin or a foaming resin ; or powdered nylon, polycarbonate, or polymethyl methacrylate may be used and be bonded by heat softening and compression. Except for a sintered ceramic the members 3 or 13 may be moulded in the case 1 or within the ring 12.
GB3878758A 1958-12-02 1958-12-02 Improvements in or relating to electro-acoustic transducers Expired GB881584A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB2138257A GB832276A (en) 1958-12-02 1957-07-05 Improvements in or relating to electro-acoustic transducers
GB3878758A GB881584A (en) 1958-12-02 1958-12-02 Improvements in or relating to electro-acoustic transducers

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3878758A GB881584A (en) 1958-12-02 1958-12-02 Improvements in or relating to electro-acoustic transducers

Publications (1)

Publication Number Publication Date
GB881584A true GB881584A (en) 1961-11-08

Family

ID=10405688

Family Applications (2)

Application Number Title Priority Date Filing Date
GB2138257A Expired GB832276A (en) 1958-12-02 1957-07-05 Improvements in or relating to electro-acoustic transducers
GB3878758A Expired GB881584A (en) 1958-12-02 1958-12-02 Improvements in or relating to electro-acoustic transducers

Family Applications Before (1)

Application Number Title Priority Date Filing Date
GB2138257A Expired GB832276A (en) 1958-12-02 1957-07-05 Improvements in or relating to electro-acoustic transducers

Country Status (1)

Country Link
GB (2) GB832276A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3310628A (en) * 1962-07-27 1967-03-21 Internat Standard Electric Com Condenser microphones
US3654403A (en) * 1969-05-01 1972-04-04 Chester C Pond Electrostatic speaker
US3689709A (en) * 1969-10-31 1972-09-05 Non Acoustic Audio Corp Electrostatic electroacoustic transducer
US3787642A (en) * 1971-09-27 1974-01-22 Gte Automatic Electric Lab Inc Electrostatic transducer having resilient electrode
US3944756A (en) * 1975-03-05 1976-03-16 Electro-Voice, Incorporated Electret microphone
US3963881A (en) * 1973-05-29 1976-06-15 Thermo Electron Corporation Unidirectional condenser microphone
US4361735A (en) * 1977-08-24 1982-11-30 The Post Office Electret microphone circuit

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3108162A (en) * 1960-04-11 1963-10-22 Schindler Mark Capacitor acousto-electric transducer and method of making the same
US3504137A (en) * 1965-12-10 1970-03-31 Tesla Np Condenser microphone with improved acoustical circuit
USRE28420E (en) * 1967-05-15 1975-05-13 Blbctret acoustic transducer
US3980838A (en) * 1974-02-20 1976-09-14 Tokyo Shibaura Electric Co., Ltd. Plural electret electroacoustic transducer
US4249043A (en) * 1977-12-02 1981-02-03 The Post Office Electret transducer backplate, electret transducer and method of making an electret transducer
EP2692144B1 (en) 2011-03-30 2017-02-01 Kaetel Systems GmbH Loudspeaker

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3310628A (en) * 1962-07-27 1967-03-21 Internat Standard Electric Com Condenser microphones
US3654403A (en) * 1969-05-01 1972-04-04 Chester C Pond Electrostatic speaker
US3689709A (en) * 1969-10-31 1972-09-05 Non Acoustic Audio Corp Electrostatic electroacoustic transducer
US3787642A (en) * 1971-09-27 1974-01-22 Gte Automatic Electric Lab Inc Electrostatic transducer having resilient electrode
US3963881A (en) * 1973-05-29 1976-06-15 Thermo Electron Corporation Unidirectional condenser microphone
US3944756A (en) * 1975-03-05 1976-03-16 Electro-Voice, Incorporated Electret microphone
US4361735A (en) * 1977-08-24 1982-11-30 The Post Office Electret microphone circuit

Also Published As

Publication number Publication date
GB832276A (en) 1960-04-06

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