US3418437A - Electro-acoustic transducer having a resonator cavity damped - Google Patents
Electro-acoustic transducer having a resonator cavity damped Download PDFInfo
- Publication number
- US3418437A US3418437A US471367A US47136765A US3418437A US 3418437 A US3418437 A US 3418437A US 471367 A US471367 A US 471367A US 47136765 A US47136765 A US 47136765A US 3418437 A US3418437 A US 3418437A
- Authority
- US
- United States
- Prior art keywords
- electro
- capillary
- membrane
- diaphragm
- acoustic transducer
- 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
Links
- 239000012528 membrane Substances 0.000 description 19
- 238000013016 damping Methods 0.000 description 16
- 230000001057 ionotropic effect Effects 0.000 description 11
- 230000008878 coupling Effects 0.000 description 10
- 238000010168 coupling process Methods 0.000 description 10
- 238000005859 coupling reaction Methods 0.000 description 10
- 210000001601 blood-air barrier Anatomy 0.000 description 7
- 239000004744 fabric Substances 0.000 description 5
- 229920000867 polyelectrolyte Polymers 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 4
- 239000000835 fiber Substances 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000012237 artificial material Substances 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
-
- 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
- H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Health & Medical Sciences (AREA)
- Otolaryngology (AREA)
- Electrostatic, Electromagnetic, Magneto- Strictive, And Variable-Resistance Transducers (AREA)
- Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
Description
. 24, I968 H. HOFFMANN ELECTRO'ACOUSTIC TRANSDUCER HAVING A RESONATOR CAVITY DAMPED Filed July 12, 1965 L m. EP mm 2 M CA Y Rmwm A M R L MOM N w United States Patent 3,418,437 ELECTRO-ACOUSTIC TRANSDUCER HAVING A RESONATOR CAVITY DAMPED Helmut Hotfmann Munich, Germany, assignor to Siemens Aktiengesellschaft, Munich, Germany Filed July 12, 1965, Ser. No. 471,367 Claims priority, application Germany, July 29, 1964,
S 92,323, S 92,326 4 Claims. (Cl. 179-1155) ABSTRACT OF THE DISCLOSURE Electro-acoustic transducer having at least one resonator chamber with at least one opening provided with a damping cover, said cover comprising the capillary zone of an ionotropic membrane.
This invention concerns an electro-acoustic transducer, and more particularly, such a transducer having a resonator cavity provided with a coupling opening having a damping cover. Such covers are used, for example, to improve the oscillation behavior of the diaphragm of a transducer such as by compensation for the resonance of the diaphragm.
In the past, cloth discs, usually silk, have been used for such damping covers. However, the characteristics of cloth which determine its damping resistance are themselves dependent on various factors, such as the roughness of the fiber, the diameter of the fiber, the fiber separation, and also on the process used in the production of the cloth, including the stresses to which the finished cloth is subjected, as by stretching. Experience has shown that cloths used for damping covers have such great differences in these characteristics that it is very difiicult to obtain cloths of the same required characteristics.
It is an object of this invention to avoid these dis advantages of cloth damping covers and to provide covers of uniform repeatable characteristics, which are readily controlled in the manufacturing process.
The objects of the invention are achieved through use of the capillary zone of an ionotropic membrane as a damping cover. Such a membrane can be produced by ionic diffusion into polyelectrolytes in accordance with processes such as those described in German Patents Nos. 1,011,853 and 1,108,665 in the name of Dr. Heinrich Thiele. Such process is also disclosed, inter alia, in British Patent No. 918,626.
As indicated in German Patents 1,011,853 and 1,101,665 ionotropic membranes are formed employing polyuronides as polyelectrolytes and polyvalent ions such as lead, copper, cadmium and calcium. The polyvalent ion is permitted to diffuse into the polyelectrolyte to form straight, parallel and uniform capillaries as the polyelectrolyte coagulates into a membrane.
In the production of such membranes, there is first formed a dense primary membrane upon which a droplike separating zone is formed, with an adjoining capillary zone then formed. The diameters of the capillary tubes can be controlled by variation of the chain length and concentration of the polyelectrolyte, as well as the radius and valence of the diffused ion. The capillary zone of the membrane can be separated and stabilized by, for instance, introducing an artificial material into the walls thereof.
The utilization of such capillary zones as damping covers for coupling openings of resonator chambers in electro-acoustic transducers has the advantage that the covering repetitively demonstrates the characteristics causing the desired damping, practically free of tolerance dif- 3,418,437 Patented Dec. 24, 1968 ferences. Further, it has the equally important advantage that the size of the pores or capillary tubes can be controlled in the desired manner during the production of the membranes so that the characteristics of the membrane determining the desired damping can thus be adapted to the prevailing conditions in a given case.
In the case of electro-aconstic transducers having at least one resonator chamber closed off on one side by a vibratory diaphragm, with the resonator chamber coupled to the outer chamber of the diaphragm through at least one opening provided in the diaphragm, a damping cover according to the invention can be achieved in a particularly simple fashion. In such case, the vibrating diaphragm itself can be formed by an ionotropic capillary membrane, with the previously mentioned dense primary membrane forming the main body of the diaphragm but being removed from the capillary zone thereof over a portion of the membrane corresponding to the coupling opening. The exposed capillary zone then forms the damping cover of the coupling opening, as before. At the same time, another advantage is realized, since an ionotropic capillary membrane possesses a very desirable structure for use as a vibratory diaphragm, because of the complete uniformity of its construction and because of the low weight thereof due to the large number of capillary tubes therein.
The invention will now be more fully described in conjunction with an illustrative embodiment thereof shown in the accompanying drawing.
In the drawing, the single figure is a cross-sectional view of a dynamic microphone constructed in accordance with the invention.
The microphone includes a casing 1 mounting a permanent magnet 2 carrying a central pole plate 3 which is radially inward of an annular pole ring 4 fixed to the casing. A vibration diaphragm 5 carries the usual moving coil 6 and is clamped between spacing rings 7 and 8, covered by perforated lid or cover 9.
The annular pole ring 4 has a pair of openings or passages 10 and 11, therethrough, to provide for acoustic coupling to the resonator cavities 12 and 13, respectively. These passages are provided with respective damping covers 14 and 15, the damping covers being formed by the capillary zones of ionotropic capillary membranes.
The diaphragm 5 is similarly provided with a coupling opening 16 which couples the outer chamber between the cover 9 and diaphragm 5 with the inner chamber including resonator cavities 12 and 13. As indicated above, the vibratory diaphragm 5 may itself be an ionotropic capillary membrane with the dense primary membrane facing the cover 9, but with a portion of that primary membrane removed to form the coupling opening or passage 16. Then, the remaining capillary zone of the membrane forms the damping cover for such passage.
It will be obvious that the invention is applicable to other forms of transducers than that specifically shown and described herein. Accordingly, the invention should not be considered limited to such showing, but rather only by the appended claims.
I claim:
1. In an electro-acoustic transducer having a resonator chamber coupled to a sound source by an opening through a wall thereof, a damping cover for such opening formed by the capillary zone of an ionotropic capillary mem' brane.
2. An electro-acoustic transducer having a resonator chamber and a vibratory diaphragm forming a wall of said chamber and provided with an acoustic passage therethrough for coupling the chamber to a sound source, the diaphragm being an ionotropic capillary membrane having a dense primary membrane layer at one side thereof and a capillary zone at the opposite side, the acoustic passage being formed by a portion of the capillary zone not covered by said primary membrane layer.
3. A dynamic microphone including a casing having a perforate cover thereon for acoustic coupling inward thereof, a permanent magnet, means defining a magnetic circuit for said permanent magnet with a cylindrical air gap therein, a vibratory diaphragm mounted adjacent said cover in said casing and carrying a moving coil extending into said cylindrical air gap to develop .a voltage thereacross in response to vibration of the diaphragm, said diaphragm being an ionotropic capillary membrane having a dense primary membrane layer next adjacent said cover and a capillary zone at the opposite side thereof, and an acoustic passage through said diaphragm formed by a portion of the capillary zone not covered by said primary 15 membrane layer.
4. The apparatus of claim 3 in which said means defining a magnetic circuit includes an annular pole ring mourted in said casing and having at least one acoustic passage therethrough for sound coupling purposes, said passage being covered by the capillary zone of an ionotropic capillary membrane.
No references cited.
KATHLEEN H. CLAFFY, Primary Examiner.
A. MCGILL, Assistant Examiner.
US. Cl. X.R.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DES92326A DE1216367B (en) | 1964-07-29 | 1964-07-29 | Electroacoustic transducer with at least one resonator chamber, which is coupled through an opening provided with a damping cover |
DES92323A DE1259949B (en) | 1964-07-29 | 1964-07-29 | Electroacoustic converter with acoustically effective spaces on both sides of a vibrating membrane |
Publications (1)
Publication Number | Publication Date |
---|---|
US3418437A true US3418437A (en) | 1968-12-24 |
Family
ID=25997735
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US471367A Expired - Lifetime US3418437A (en) | 1964-07-29 | 1965-07-12 | Electro-acoustic transducer having a resonator cavity damped |
Country Status (6)
Country | Link |
---|---|
US (1) | US3418437A (en) |
BE (1) | BE667646A (en) |
DE (2) | DE1259949B (en) |
GB (1) | GB1082433A (en) |
NL (1) | NL6509262A (en) |
SE (1) | SE313598B (en) |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3646281A (en) * | 1969-06-02 | 1972-02-29 | Rdf West | Electrostatic transducer with vented diaphragm |
US3930560A (en) * | 1974-07-15 | 1976-01-06 | Industrial Research Products, Inc. | Damping element |
US4005278A (en) * | 1974-09-16 | 1977-01-25 | Akg Akustische U. Kino-Gerate Gesellschaft M.B.H. | Headphone |
US4030564A (en) * | 1973-06-28 | 1977-06-21 | Pioneer Electronic Corporation | Loud speaker with stable damping |
US4602245A (en) * | 1983-04-29 | 1986-07-22 | Ensco, Inc. | General purpose modular acoustic signal generator |
US4843628A (en) * | 1986-07-10 | 1989-06-27 | Stanton Magnetics, Inc. | Inertial microphone/receiver with extended frequency response |
US4858719A (en) * | 1986-01-16 | 1989-08-22 | Akg Akustische U. Kino-Gerate Gesellschaft M.B.H. | Pressure gradient pickup |
US20060254852A1 (en) * | 2005-05-11 | 2006-11-16 | Yen-Shan Chen | Integral audio module |
US8479992B2 (en) | 2003-11-13 | 2013-07-09 | Metrologic Instruments, Inc. | Optical code symbol reading system employing an acoustic-waveguide structure for coupling sonic energy, produced from an electro-transducer, to sound wave ports formed in the system housing |
US20150256922A1 (en) * | 2012-10-18 | 2015-09-10 | Nokia Technologies Oy | Resonance Damping for Audio Transducer Systems |
US10299030B2 (en) * | 2015-03-25 | 2019-05-21 | Goertek Inc. | Speaker module with sealed cavity and a communicating hole |
USD867346S1 (en) * | 2018-01-19 | 2019-11-19 | Dynamic Ear Company B.V. | Ambient filter |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3530869A1 (en) * | 1985-08-29 | 1987-03-12 | Sennheiser Electronic | Diaphragm for an electro-acoustic reproduction transducer |
-
1964
- 1964-07-29 DE DES92323A patent/DE1259949B/en active Pending
- 1964-07-29 DE DES92326A patent/DE1216367B/en active Pending
-
1965
- 1965-07-12 US US471367A patent/US3418437A/en not_active Expired - Lifetime
- 1965-07-16 NL NL6509262A patent/NL6509262A/xx unknown
- 1965-07-28 GB GB32217/65A patent/GB1082433A/en not_active Expired
- 1965-07-29 BE BE667646D patent/BE667646A/xx unknown
- 1965-07-29 SE SE9982/65A patent/SE313598B/xx unknown
Non-Patent Citations (1)
Title |
---|
None * |
Cited By (16)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3646281A (en) * | 1969-06-02 | 1972-02-29 | Rdf West | Electrostatic transducer with vented diaphragm |
US4030564A (en) * | 1973-06-28 | 1977-06-21 | Pioneer Electronic Corporation | Loud speaker with stable damping |
US3930560A (en) * | 1974-07-15 | 1976-01-06 | Industrial Research Products, Inc. | Damping element |
US4005278A (en) * | 1974-09-16 | 1977-01-25 | Akg Akustische U. Kino-Gerate Gesellschaft M.B.H. | Headphone |
US4602245A (en) * | 1983-04-29 | 1986-07-22 | Ensco, Inc. | General purpose modular acoustic signal generator |
US4858719A (en) * | 1986-01-16 | 1989-08-22 | Akg Akustische U. Kino-Gerate Gesellschaft M.B.H. | Pressure gradient pickup |
US4843628A (en) * | 1986-07-10 | 1989-06-27 | Stanton Magnetics, Inc. | Inertial microphone/receiver with extended frequency response |
US8479992B2 (en) | 2003-11-13 | 2013-07-09 | Metrologic Instruments, Inc. | Optical code symbol reading system employing an acoustic-waveguide structure for coupling sonic energy, produced from an electro-transducer, to sound wave ports formed in the system housing |
US9104930B2 (en) | 2003-11-13 | 2015-08-11 | Metrologic Instruments, Inc. | Code symbol reading system |
US20060254852A1 (en) * | 2005-05-11 | 2006-11-16 | Yen-Shan Chen | Integral audio module |
US20150256922A1 (en) * | 2012-10-18 | 2015-09-10 | Nokia Technologies Oy | Resonance Damping for Audio Transducer Systems |
US20170289674A1 (en) * | 2012-10-18 | 2017-10-05 | Nokia Technologies Oy | Resonance Damping for Audio Transducer Systems |
US9813802B2 (en) * | 2012-10-18 | 2017-11-07 | Nokia Technologies Oy | Resonance damping for audio transducer systems |
US10085086B2 (en) * | 2012-10-18 | 2018-09-25 | Nokia Technologies Oy | Resonance damping for audio transducer systems |
US10299030B2 (en) * | 2015-03-25 | 2019-05-21 | Goertek Inc. | Speaker module with sealed cavity and a communicating hole |
USD867346S1 (en) * | 2018-01-19 | 2019-11-19 | Dynamic Ear Company B.V. | Ambient filter |
Also Published As
Publication number | Publication date |
---|---|
SE313598B (en) | 1969-08-18 |
BE667646A (en) | 1966-01-31 |
DE1259949B (en) | 1968-02-01 |
GB1082433A (en) | 1967-09-06 |
NL6509262A (en) | 1966-01-31 |
DE1216367B (en) | 1966-05-12 |
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