EP0516471A1 - Magnetische Antriebsystem für Lautsprecher - Google Patents

Magnetische Antriebsystem für Lautsprecher Download PDF

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Publication number
EP0516471A1
EP0516471A1 EP92304950A EP92304950A EP0516471A1 EP 0516471 A1 EP0516471 A1 EP 0516471A1 EP 92304950 A EP92304950 A EP 92304950A EP 92304950 A EP92304950 A EP 92304950A EP 0516471 A1 EP0516471 A1 EP 0516471A1
Authority
EP
European Patent Office
Prior art keywords
chassis
magnet assembly
drive unit
diaphragm
secured
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.)
Withdrawn
Application number
EP92304950A
Other languages
English (en)
French (fr)
Inventor
Lawrence Reginald Fincham
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.)
KH Technology Corp
Original Assignee
KEF Electronics Ltd
KH Technology Corp
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
Application filed by KEF Electronics Ltd, KH Technology Corp filed Critical KEF Electronics Ltd
Publication of EP0516471A1 publication Critical patent/EP0516471A1/de
Withdrawn legal-status Critical Current

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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
    • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
    • 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
    • H04R2400/00—Loudspeakers
    • H04R2400/11—Aspects regarding the frame of loudspeaker transducers
    • 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
    • H04R9/025—Magnetic circuit
    • 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
    • H04R9/06—Loudspeakers

Definitions

  • This invention relates to loudspeaker drive units for sound reproduction and in particular to a construction of magnetic drive system for such loudspeaker drive units.
  • Loudspeaker drive units include a sound radiating diaphragm, commonly of conical form, which is caused to vibrate by a drive system to generate the radiated sound waves.
  • the mouth of the diaphragm is mounted by means of a compliant surround to a chassis of the loudspeaker drive unit to permit axial movement of the cone relative to the chassis.
  • the drive system comprises a magnet assembly rigidly mounted on the chassis of the loudspeaker drive unit.
  • the magnet assembly includes an annular air gap in a magnetic path such that there is magnetic flux across the air gap.
  • the diaphragm carries a cylindrical coil which is located concentrically with the annular air gap and at least a part of the length of the coil is within the annular air gap and is electromagnetically coupled with the magnetic flux in the annular air gap. Electric current is passed through the coil and hence a force is generated which causes the diaphragm to move away from its rest position. Accordingly if the current in the coil is a waveform representing sound signals, the diaphragm will be driven to move in a manner such as to reproduce those sound signals.
  • the diaphragm when the diaphragm is driven in this manner the movement of the diaphragm causes pressure variations in the air adjacent thereto and this requires a substantial magnitude of power to be input to the coil of the loudspeaker drive unit in order to drive the diaphragm to produce the required magnitude of sound level.
  • the diaphragm has a finite mass which, although it is low, requires significant magnitude of force to overcome the inertia of the mass of the diaphragm.
  • an electric current is passed through the coil to produce a force to drive the diaphragm the magnet assembly is subjected to an equal and opposite re-action force
  • the chassis of the speaker is in the form of a generally conical basket comprising a front annular flange and a number of legs, extending rearwardly and inwardly from the flange, to which the magnet assembly is rigidly secured.
  • the mouth of the conical diaphragm is mounted by a compliant surround to the front annular flange of the chassis and this front flange forms a mounting means for the loudspeaker drive unit.
  • the loudspeaker drive unit is mounted on a baffle board forming a wall of a box or cabinet.
  • a circular aperture is provided in the baffle board and the front chassis flange is secured to the board surrounding the aperture with the remainder of the chassis and the magnet assembly of the loudspeaker drive unit extending into the interior of the box.
  • the overall sound produced by the loudspeaker drive unit when mounted on the baffle board of the box comprises the combination of the sound radiated by the diaphragm together with any sound radiated by the chassis flange and the baffle board due to vibration thereof resulting from the re-action forces acting on the magnet assembly.
  • the loudspeaker drive unit is mounted by means of resilient or compliant mountings it is necessary to provide a compliant sealing ring to seal between the front of the chassis and the baffle board. While this method may enable the chassis of the loudspeaker drive unit to be mechanically isolated from the baffle board so that any sound radiation from the baffle board due to reaction forces acting on the magnet assembly is eliminated or reduced the front flange of the chassis itself presents a significant sound radiating surface which can radiate sound which will interfere with that radiated by the diaphragm and result in distortion of the reproduced sound.
  • a loudspeaker drive unit comprises a chassis; a magnet assembly including an annular air gap, magnetic flux being generated in the air gap by a magnet; a diaphragm having a periphery thereof secured by compliant means to the chassis; a drive coil secured to the diaphragm and located in the magnetic flux of the air gap so that passage of electric current through the drive coil generates a drive force acting between the magnet assembly and the diaphragm to cause the diaphragm to vibrate; and wherein the magnetic structure is mechanically isolated or de-coupled from the chassis to prevent or reduce transmission to the chassis of re-action force arising from said drive force.
  • a chassis 10 of a loudspeaker drive unit comprises a front annular flange 11 from which legs 12 extend rearwardly and inwardly. The rear ends of the legs 12 are joined by a rear member in the form of an annular plate 13.
  • the chassis may be of cast construction but is conveniently pressed from sheet metal. preferably three legs 12 equi-angularly spaced on the flange 11 are provided but if desired a larger number of legs may be provided.
  • a magnet assembly 14 is secured to the annular plate 13.
  • the magnet assembly 14 comprises an annular magnet 17, a first pole element 18 having a circular flange 19 magnetically coupled to one pole face of the magnet 17 and a cylindrical centre pole 20 extending from the flange 19 through the magnet 17 and a second pole element comprising a front plate 21 magnetically coupled to the other pole face of the magnet 17.
  • the front plate 21 is of annular form with a central aperture therein of greater diameter than the diameter of the centre pole 20.
  • the centre pole 20 extends through the aperture in the front plate 21 to define, between them, an annular air gap concentric with a centre line 22.
  • the larger diameter front edge of the conical diaphragm 15 is secured to the front flange 11 of the chassis 10 by means of a compliant surround 23.
  • a cylindrical coil former 24 is secured to the rear smaller diameter of the conical diaphragm 15.
  • the coil former 24 carries a drive coil for the conical diaphragm.
  • the inner diameter of the coil former 24 is slightly larger than the diameter of the centre pole 20 and the outer diameter of the drive coil on the coil former is slightly smaller than the diameter of the aperture in the front plate 21.
  • the coil former extends rearwardly from the diaphragm 15 through the air gap between the centre pole 20 and the front plate 21 such that the drive coil is located in the region of the air gap and is subjected to magnetic flux generated by the magnet 17 in the air gap.
  • Centering means 25 is secured to the coil former 24 to maintain the coil former, and the drive coil carried thereby, concentric relative to the centre line 22 of the annular air gap.
  • the centering means may comprise, as shown in the drawing, an annular sheet formed with concentric corrugations therein whereby the conical diaphragm 15 is free to move in an axial direction on the compliant mounting ring 23 relative to the chassis 10 while being maintained concentric relative to the axis 22.
  • An outer edge of the centering means 25 is secured to a surface of an annular member 27 which is attached to the magnet assembly 14.
  • the magnet assembly 14 is mounted on the chassis 10 in such a manner that the magnet assembly is mechanically isolated or decoupled from the chassis 10.
  • the mechanical isolation or de-coupling of the magnet assembly 14 from the chassis 10 is achieved by means of resilient mountings 41, only one of which is illustrated in the drawing, for the magnet assembly.
  • Each mounting 41 comprises a resilient bush member located in an aperture in the rear plate 13.
  • the resilient bush member comprises an inner tubular element 35 and an outer annular element 36 interconnected by a web 37.
  • the outer annular element 36 has an annular groove in the periphery thereof to receive the edge of the plate 13.
  • a rigid tubular member 38 extends through the inner tubular element 35.
  • the tubular member 38 is carried by the member 27.
  • the front plate 21 of the magnet assembly extends out to the locations of the mountings 41 and is secured to the tubular members 38 by screws 39 and nuts 40.
  • the outer annular element of the resilient bush members is held by the plate 13 and the inner tubular element 35 is secured to the front plate 21 by means of the tubular spigot 38 engaging in the tubular element 35 and by the tubular spigot 38 being secured to the front plate 21 by the screws 39 and nuts 40.
  • the nuts 40 are held captive in recesses in the member 27. Accordingly it will be appreciated that the magnet assembly 14 is resiliently connected to the chassis by means of the webs 37 of the resilient bush members.
  • the webs permit movement of the magnet assembly relative to the chassis 10 in the direction of the axis 22 and it is in this direction that vibration of the magnet assembly due to the re-action forces will occur. Therefore the resilient bush members mechanically isolate or de-couple the magnet assembly from the chassis 10 in respect of vibration of the magnet assembly resulting from re-action forces when the diaphragm 15 is driven. However the webs of the bush members resist movement of the magnet assembly in directions transverse to the axis 22 and hence the axis 22 of the magnet assembly and the air gap therein is maintained substantially concentric with the axis of the chassis 10 regardless of the orientation of the loudspeaker drive unit.
  • the diaphragm While in general the low frequency diaphragm is of conical form, the diaphragm may be of other forms as may be desired.
  • the diaphragm may be planar with the periphery thereof mounted by compliant means to a chassis of the drive unit and the drive coil secured to a central region of the diaphragm.
  • the chassis of the loudspeaker drive unit has been described as a unitary structure with the magnet assembly mounted thereon by means of resilient mountings secured to the magnet assembly and to the plate 13.
  • the chassis may comprise two parts which are connected together but mechanically isolated or decoupled from one another by resilient mounting means.
  • One part of the chassis includes the front flange and the other part of the chassis comprises a sub-chassis which includes the rear member.
  • the front flange may have legs extending rearwardly and the rear member may have legs extending forwardly and connection between the two parts of the chassis may be effected by resilient mounting means secured to corresponding pairs of legs of the chassis and sub-chassis.
  • the magnet assembly may be rigidly secured to the rear sub-chassis.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Otolaryngology (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Details Of Audible-Bandwidth Transducers (AREA)
EP92304950A 1991-05-31 1992-05-29 Magnetische Antriebsystem für Lautsprecher Withdrawn EP0516471A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9111737 1991-05-31
GB9111737A GB2256560B (en) 1991-05-31 1991-05-31 Loudspeaker

Publications (1)

Publication Number Publication Date
EP0516471A1 true EP0516471A1 (de) 1992-12-02

Family

ID=10695878

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92304950A Withdrawn EP0516471A1 (de) 1991-05-31 1992-05-29 Magnetische Antriebsystem für Lautsprecher

Country Status (6)

Country Link
EP (1) EP0516471A1 (de)
CA (1) CA2109711A1 (de)
GB (1) GB2256560B (de)
NO (1) NO934298L (de)
NZ (1) NZ242962A (de)
WO (1) WO1992022175A1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5682435A (en) * 1994-11-04 1997-10-28 U.S. Philips Corporation Apparatus comprising a baffle and a loudspeaker, and loudspeaker for use in the apparatus
WO2003034778A2 (de) * 2001-10-08 2003-04-24 Kolja Willimzik Elektroakustisches gerät und qualitätskontrollverfahren
WO2013083989A1 (en) * 2011-12-06 2013-06-13 B & W Group Ltd Decoupled drive unit for a loudspeaker enclosure
US9498524B2 (en) 2007-04-16 2016-11-22 Corium International, Inc. Method of vaccine delivery via microneedle arrays
WO2021134429A1 (zh) * 2019-12-31 2021-07-08 瑞声声学科技(深圳)有限公司 一种扬声器箱
FR3138258A1 (fr) 2022-07-19 2024-01-26 Cédric Carlavan Haut-parleur et meuble equipe d’un tel haut-parleur

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3667568A (en) * 1970-09-15 1972-06-06 Arthur Liebscher Pressure compensator for speaker cabinets
GB2001827A (en) * 1977-07-25 1979-02-07 Sony Corp Dynamic loudspeakers
EP0158978A2 (de) * 1984-04-17 1985-10-23 Jürgen Dipl.-Ing. Quaas Einbau von Schallwandlern in eine Schallführung, insbesondere für Lautsprecher, vorzugsweise für Lautsprecherboxen
DE3705724A1 (de) * 1986-02-24 1987-09-17 Pioneer Electronic Corp Lautsprechersystem
FR2625639A1 (fr) * 1987-12-30 1989-07-07 Kobus Stanislas Dispositif de fixation pour haut-parleur electrodynamique
DE3841946A1 (de) * 1988-04-30 1989-11-09 Pioneer Electronic Corp Lautsprechereinrichtung

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1508348A (en) * 1975-06-10 1978-04-26 Mark Products Seismometer

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3667568A (en) * 1970-09-15 1972-06-06 Arthur Liebscher Pressure compensator for speaker cabinets
GB2001827A (en) * 1977-07-25 1979-02-07 Sony Corp Dynamic loudspeakers
EP0158978A2 (de) * 1984-04-17 1985-10-23 Jürgen Dipl.-Ing. Quaas Einbau von Schallwandlern in eine Schallführung, insbesondere für Lautsprecher, vorzugsweise für Lautsprecherboxen
DE3705724A1 (de) * 1986-02-24 1987-09-17 Pioneer Electronic Corp Lautsprechersystem
FR2625639A1 (fr) * 1987-12-30 1989-07-07 Kobus Stanislas Dispositif de fixation pour haut-parleur electrodynamique
DE3841946A1 (de) * 1988-04-30 1989-11-09 Pioneer Electronic Corp Lautsprechereinrichtung

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5682435A (en) * 1994-11-04 1997-10-28 U.S. Philips Corporation Apparatus comprising a baffle and a loudspeaker, and loudspeaker for use in the apparatus
WO2003034778A2 (de) * 2001-10-08 2003-04-24 Kolja Willimzik Elektroakustisches gerät und qualitätskontrollverfahren
WO2003034778A3 (de) * 2001-10-08 2004-11-25 Kolja Willimzik Elektroakustisches gerät und qualitätskontrollverfahren
US9498524B2 (en) 2007-04-16 2016-11-22 Corium International, Inc. Method of vaccine delivery via microneedle arrays
WO2013083989A1 (en) * 2011-12-06 2013-06-13 B & W Group Ltd Decoupled drive unit for a loudspeaker enclosure
US9241206B2 (en) 2011-12-06 2016-01-19 B & W Group Ltd Decoupled drive unit for a loudspeaker enclosure
WO2021134429A1 (zh) * 2019-12-31 2021-07-08 瑞声声学科技(深圳)有限公司 一种扬声器箱
FR3138258A1 (fr) 2022-07-19 2024-01-26 Cédric Carlavan Haut-parleur et meuble equipe d’un tel haut-parleur

Also Published As

Publication number Publication date
GB2256560A (en) 1992-12-09
NZ242962A (en) 1994-10-26
GB2256560B (en) 1994-11-23
NO934298D0 (no) 1993-11-26
NO934298L (no) 1993-11-26
WO1992022175A1 (en) 1992-12-10
CA2109711A1 (en) 1992-12-10
GB9111737D0 (en) 1991-07-24

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