US3780232A - Loudspeaker diaphragm - Google Patents

Loudspeaker diaphragm Download PDF

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Publication number
US3780232A
US3780232A US00215332A US3780232DA US3780232A US 3780232 A US3780232 A US 3780232A US 00215332 A US00215332 A US 00215332A US 3780232D A US3780232D A US 3780232DA US 3780232 A US3780232 A US 3780232A
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US
United States
Prior art keywords
dome portion
surround
electro
dome
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
Application number
US00215332A
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English (en)
Inventor
L Ward
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.)
ROLA CELESTION Ltd
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ROLA CELESTION Ltd
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Publication date
Application filed by ROLA CELESTION Ltd filed Critical ROLA CELESTION Ltd
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Publication of US3780232A publication Critical patent/US3780232A/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
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/12—Non-planar diaphragms or cones
    • H04R7/127—Non-planar diaphragms or cones dome-shaped
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/16—Mounting or tensioning of diaphragms or cones
    • H04R7/18—Mounting or tensioning of diaphragms or cones at the periphery
    • H04R7/22—Clamping rim of diaphragm or cone against seating

Definitions

  • An electro-acoustic 179/1 R, 1 1 F 0; 1 1 31 R, 32 R transducer incorporating the diaphragm has a totally enclosed chamber to the rear of the voice coil.
  • the [56] References Cited diaphragm assembly is particularly suited to the fre- UNITED STATES PATENTS quency range of 500 c/s to 5 Kc/s at powers of up to 50 watts. 3,328,537 6/l967 Hecht 181/32 R 2,442,791 6/1948 Wente 179/181 R 9 Claims, 4 Drawing Figures LOUDSPEAKER DIAPHRAGM BACKGROUND TO THE INVENTION 1.
  • This invention relates to diaphragm assemblies for electro-acoustic transducers, particularly loudspeakers.
  • the invention is also concerned with electroacoustic transducers incorporating such diaphragm assemblies, and more particularly with a mid-range soft dome pressure loudspeaker.
  • Diaphragm assemblies of many different forms have been devised for use in loudspeakers of the moving-coil type.
  • the diaphragm cone is formed from a layer of woven fabric impregnated with a hardened synthetic resin and with a layer of compacted fibrous material bonded thereto. This results in a diaphragm having a substantial degree of rigidity and stiffness and is designed to give a good response at high frequencies.
  • the diaphragm in which the diaphragm is of the dome type having its concave face towards the coil, the diaphragm comprises a soft fabric dome which is first impregnated to render it self-sustaining and yieldable but leaving the fabric interstices open, and which is then coated with a soft film closing the fabric interstices, rendering the diaphragm impervious to air and defining a radiating area.
  • the coil is then fixed to a short axial flange at the periphery of the composite diaphragm.
  • This diaphragm assembly is designed for use in the range 2,000 to 18,000 cycles per second.
  • a diaphragm assembly for an electro-acoustic transducer comprising a soft dome portion of resilient, self-sustaining character, and a semirigid surround secured to the periphery of the dome portion to extend substantially radially of the central axis of the dome portion, the combination being such that when said surround is firmly clamped 'at its periphery both the dome portion and the surround are able to undergo substantial excursions in response to signals applied to a coil secured to said combination.
  • the surround is corrugated over a part of its area and is formed from a fabric base impregnated with a hardenable synthetic resin.
  • An electro-acoustic transducer in accordance with the invention comprises a diaphragm assembly in accordance with the invention and includes magnetic circuit means generating a flux effective on said coil, and housing means defining a totally enclosed chamber to the rear of the coil.
  • FIG. 1 is a longitudinalcross-sectional view through the loudspeaker
  • FIGS. 2A, 2B and 2C in combination comprise an exploded view of the loudspeaker illustrating in greater detail the various components and their interrelationship.
  • the loudspeaker illustrated in the drawings is a midrange soft dome pressure loudspeaker designed primarily to operatebetween the range of 500 c/s and 5 Kc/s, but which will operate 3db up to 10 Kc/s.
  • the power handling capacity is watts to the DIN 45-500 specification.
  • the harmonic distortion is extremely low and can be better than 2 percent throughout the working range.
  • the loudspeaker basically comprises a front mounting assembly, a diaphragm assembly, a magnet assembly and a back pressure system.
  • an annular mounting plate 10 At the front of the loudspeaker is an annular mounting plate 10 provided with appropriate holes to receive brass screws 12 and dowels 13.
  • Behind the mounting plate 10 and arranged to fit into a recess 11 in the rear of the plate is an annular strip 14 of a synthetic material such as Tesamol.
  • a protective grill 16 of domed configuration is adapted to fit into the central aperture in the mounting plate 10 with its peripheral flange l7 seating against a radially inwardly projecting flange provided on the mounting plate 10.
  • the diaphragm assembly which is shown in exploded view in FIG. 2A comprises a stainless steel diaphragm housing 22 of annular shape and having a central aperture therethrough; a pair of rubber clamping washers 24 which are seated when assembled against a shoulder 25 of the housing 22; a soft dome 26; a diaphragm surround 28; the beryllium strips 20; and a coil 30 mounted on a former 31.
  • the surround 28 although semi-rigid must be able to follow the movements of the soft dome 26 and thus has the ability to make a large excursion from its rest position. This is particularly important in providing a low resonance without distortion, especially when the loudspeaker has to handle input signals of high power, for example of the order of 50 watts.
  • a termination washer 32 which is also of annular shape and which includes electrical connection tags 33 adjacent to its periphery.
  • the beryllium strips 20 leading to the coil are soldered to the tags 33.
  • the magnet assembly which is shown in detail in FIG. 2B.
  • the magnet assembly comprises an annular pole piece 34 which has a radially prominent portion 39 adjacent to its forward end.
  • the forward end of the pole piece 34 has also an axially prominent portion 35 on which is seated a perforated dome 36 which in the assembled state of the loudspeaker projects into the fabric dome 26 in substantially parallel relationship thereto.
  • the dome 36 may be made for example of perforated brass sheet material.
  • the aperture through the pole piece 34 is filled by a foam plug 37 which is normally of greater diameter than the aperture so that when assembled it is compressed and projects forwardly of the front face of the pole piece, as shown in FIG. 1.
  • the plug 37 fulfils a damping function.
  • annular foam strip 38 Around the pole piece 34 is fitted an annular foam strip 38 which, when assembled, is compressed by an annular magnet 40 surrounding the pole piece 34.
  • the magnet 40 is preferably of the ceramic type with a strength of for example 15,000 gauss.
  • the magnet assembly is held together by being secured between front and rear plates 42 and44 respectively, for example by means of brass screws 46.
  • the coil 30 is positioned in the air gap defined between the pole piece 39 and the facing surface of the front plate 42.
  • the back pressure system comprises a back pressure cover 48 substantially filled by a foam plug 50.
  • the back cover 48 fits around the rear plate 44 of the magnet assembly and is secured thereto to provide a totally enclosed back pressure system behind the coil 30. This means that the loudspeaker is not affected by the size of the cabinet in which it is mounted.
  • the diaphragm assembly of the present invention is particularly advantageous for handling large power capacity signals by its use of a semi-rigid diaphragm surround which can also undergo a large excursion to produce a low resonance without distorting.
  • An electro-acoustic transducer having a diaphragm assembly comprising a central dome portion of resilient, yieldable, self-sustaining character, a surround supporting said dome portion which is of a mate rial different from that of the dome portion and which has a greater rigidity than the dome portion, the surround having a circumferential inner marginal portion inclined to the central axis of the dome portion, the inclined portion having the dome portion rigidly secured to one face thereof so as to rigidly secure the surround to the periphery of the dome portion, the surround extending substantially radially outwardly of the central axis of the dome portion, the surround being circumferentially corrugated over a part of its area and being arranged to follow the translational movements of the dome portion, a voice coil, and a former carrying the voice coil, the former being secured to the other face of the inner marginal portion so that the voice coil is spaced axially from the dome portion on the concave side thereof.
  • said magnetic circuit means comprises an annular pole piece having a radially outwardly prominent portion defining a surface facing the coil, the pole piece being provided with a non-magnetic perforated dome at its forward end projecting into the dome portion of the diaphragm assembly and substantially parallel thereto.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Diaphragms For Electromechanical Transducers (AREA)
US00215332A 1971-01-04 1972-01-04 Loudspeaker diaphragm Expired - Lifetime US3780232A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB33171*[A GB1380914A (en) 1971-01-04 1971-01-04 Diaphragm assemblies for electro-acoustic transducers

Publications (1)

Publication Number Publication Date
US3780232A true US3780232A (en) 1973-12-18

Family

ID=9702509

Family Applications (1)

Application Number Title Priority Date Filing Date
US00215332A Expired - Lifetime US3780232A (en) 1971-01-04 1972-01-04 Loudspeaker diaphragm

Country Status (15)

Country Link
US (1) US3780232A (OSRAM)
AT (1) AT326744B (OSRAM)
BE (1) BE777617A (OSRAM)
CH (1) CH545053A (OSRAM)
DE (2) DE2166848A1 (OSRAM)
DK (1) DK138148B (OSRAM)
ES (1) ES398583A1 (OSRAM)
FI (1) FI57507C (OSRAM)
FR (1) FR2121536B1 (OSRAM)
GB (1) GB1380914A (OSRAM)
IE (1) IE35948B1 (OSRAM)
IT (1) IT945663B (OSRAM)
NL (1) NL7200036A (OSRAM)
NO (1) NO130255B (OSRAM)
SE (1) SE379474C (OSRAM)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0015013A1 (de) * 1979-02-14 1980-09-03 International Standard Electric Corporation Universelles Kalottenlautsprecher-Bauelement
DE2942573A1 (de) * 1979-08-16 1981-03-26 Stäubli AG, Horgen, Zürich Rotationsschaftmaschine
US4433214A (en) * 1981-12-24 1984-02-21 Motorola, Inc. Acoustical transducer with a slotted piston suspension
US5357587A (en) * 1992-12-23 1994-10-18 Grodinsky Robert M Distortion reduction in loudspeakers
US5878149A (en) * 1993-10-08 1999-03-02 Pioneer Electronic Corporation Loudspeaker having a yoke, magnet, cylindrical throat, and spacer plate configuration
US6351544B1 (en) 1999-12-10 2002-02-26 Harman International Industries Incorporated Regressively hinged spider
US6570995B2 (en) * 2000-11-14 2003-05-27 Sony Corporation Speaker device
US6724910B1 (en) 1999-10-04 2004-04-20 Harman International Industries, Incorporated Diaphragm stable through hygroscopic cycling
EP1047284A3 (de) * 1999-04-22 2004-12-15 AKG Acoustics GmbH Elektroakustischer Wandler für extreme Druckbelastungen
US20050180588A1 (en) * 2003-09-11 2005-08-18 Martin Opitz Transducer with deformable corner
WO2007109832A1 (en) * 2006-03-28 2007-10-04 Immersion Technology Property Limited Acoustic filter for electroacoustic transducer
US20080024036A1 (en) * 2005-02-18 2008-01-31 Martin Opitz Transducer membrane with symmetrical curvature
US20110085690A1 (en) * 2008-05-21 2011-04-14 Genus Audio Corp. Speaker
US20170034322A1 (en) * 2015-07-31 2017-02-02 Aac Technologies Pte. Ltd., Mobile terminal device

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1531791A (en) * 1976-03-17 1978-11-08 Rank Organisation Ltd Transducers
JPS5414726A (en) * 1977-07-06 1979-02-03 Hitachi Ltd Dome type speaker
DE2941644C2 (de) * 1978-10-17 1982-11-11 Matsushita Electric Industrial Co., Ltd., Kadoma, Osaka Lautsprechermembran und Verfahren zu ihrer Herstellung
JPS6042558Y2 (ja) * 1980-04-17 1985-12-27 ソニー株式会社 スピ−カ
DE3722832A1 (de) * 1987-07-03 1989-01-12 Electronic Werke Deutschland Membran fuer einen lautsprecher
CN103085338B (zh) * 2013-01-21 2014-12-10 宁海县雁苍山电力建设有限公司 模压组合纸卷筒的制造方法
GB2525429A (en) 2014-04-24 2015-10-28 Funktion One Res Loudspeaker

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442791A (en) * 1945-09-07 1948-06-08 Bell Telephone Labor Inc Acoustic device
GB763974A (en) * 1953-10-14 1956-12-19 Koepenick Funkwerk Veb Electro-acoustic transducer of the moving coil type
US2974204A (en) * 1954-07-06 1961-03-07 Kane Corp Du Transducer
US3033945A (en) * 1959-05-01 1962-05-08 Ar Inc Voice coil and diaphragm support for high frequency loud-speaker
US3328537A (en) * 1964-01-09 1967-06-27 Hecht William High frequency sound translating device
US3612783A (en) * 1967-07-05 1971-10-12 Philips Corp Foam diaphragm for loudspeaker

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US685429A (en) * 1901-02-05 1901-10-29 George Osten Diaphragm for acoustical apparatus.
GB385286A (en) * 1930-03-17 1932-12-22 Walter Greppert Improvements in and relating to diaphragms, more particularly for sound boxes of talking machines
AT193449B (de) * 1955-09-30 1957-11-25 Siemens Ag Metallmembran
DE1107712B (de) * 1958-12-31 1961-05-31 Sennheiser Electronic Verfahren zur Herstellung einer Membran

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2442791A (en) * 1945-09-07 1948-06-08 Bell Telephone Labor Inc Acoustic device
GB763974A (en) * 1953-10-14 1956-12-19 Koepenick Funkwerk Veb Electro-acoustic transducer of the moving coil type
US2974204A (en) * 1954-07-06 1961-03-07 Kane Corp Du Transducer
US3033945A (en) * 1959-05-01 1962-05-08 Ar Inc Voice coil and diaphragm support for high frequency loud-speaker
US3328537A (en) * 1964-01-09 1967-06-27 Hecht William High frequency sound translating device
US3612783A (en) * 1967-07-05 1971-10-12 Philips Corp Foam diaphragm for loudspeaker

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0015013A1 (de) * 1979-02-14 1980-09-03 International Standard Electric Corporation Universelles Kalottenlautsprecher-Bauelement
DE2942573A1 (de) * 1979-08-16 1981-03-26 Stäubli AG, Horgen, Zürich Rotationsschaftmaschine
US4433214A (en) * 1981-12-24 1984-02-21 Motorola, Inc. Acoustical transducer with a slotted piston suspension
US5357587A (en) * 1992-12-23 1994-10-18 Grodinsky Robert M Distortion reduction in loudspeakers
US5878149A (en) * 1993-10-08 1999-03-02 Pioneer Electronic Corporation Loudspeaker having a yoke, magnet, cylindrical throat, and spacer plate configuration
EP1047284A3 (de) * 1999-04-22 2004-12-15 AKG Acoustics GmbH Elektroakustischer Wandler für extreme Druckbelastungen
US6724910B1 (en) 1999-10-04 2004-04-20 Harman International Industries, Incorporated Diaphragm stable through hygroscopic cycling
US6351544B1 (en) 1999-12-10 2002-02-26 Harman International Industries Incorporated Regressively hinged spider
US6570995B2 (en) * 2000-11-14 2003-05-27 Sony Corporation Speaker device
US7711137B2 (en) 2003-09-11 2010-05-04 Akg Acoustics Gmbh Transducer with deformable corner
US20050180588A1 (en) * 2003-09-11 2005-08-18 Martin Opitz Transducer with deformable corner
US20100195862A1 (en) * 2003-09-11 2010-08-05 Akg Acoustics Gmbh Transducer with deformable corner
US8411894B2 (en) 2003-09-11 2013-04-02 AKG Acoustrics GmbH Transducer with deformable corner
US20080024036A1 (en) * 2005-02-18 2008-01-31 Martin Opitz Transducer membrane with symmetrical curvature
US8208679B2 (en) 2005-02-18 2012-06-26 Akg Acoustics Gmbh Transducer membrane with symmetrical curvature
WO2007109832A1 (en) * 2006-03-28 2007-10-04 Immersion Technology Property Limited Acoustic filter for electroacoustic transducer
US20110085690A1 (en) * 2008-05-21 2011-04-14 Genus Audio Corp. Speaker
US8848960B2 (en) * 2008-05-21 2014-09-30 Genus Audio Corp. Speaker
US20170034322A1 (en) * 2015-07-31 2017-02-02 Aac Technologies Pte. Ltd., Mobile terminal device

Also Published As

Publication number Publication date
IT945663B (it) 1973-05-10
SE379474C (sv) 1981-05-04
DE2165572C3 (de) 1981-06-19
DE2166848A1 (de) 1976-03-11
DE2165572A1 (de) 1972-07-20
IE35948B1 (en) 1976-07-07
FR2121536A1 (OSRAM) 1972-08-25
FI57507B (fi) 1980-04-30
IE35948L (en) 1972-07-04
DK138148C (OSRAM) 1979-01-08
NO130255B (OSRAM) 1974-07-29
CH545053A (de) 1973-11-30
ES398583A1 (es) 1974-09-16
NL7200036A (OSRAM) 1972-07-06
AT326744B (de) 1975-12-29
BE777617A (fr) 1972-04-17
FR2121536B1 (OSRAM) 1979-08-03
FI57507C (fi) 1980-08-11
DK138148B (da) 1978-07-17
DE2165572B2 (de) 1975-11-06
GB1380914A (en) 1975-01-15
SE379474B (OSRAM) 1975-10-06

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