WO2002001913A1 - Compact high performance speaker - Google Patents
Compact high performance speaker Download PDFInfo
- Publication number
- WO2002001913A1 WO2002001913A1 PCT/US2001/020682 US0120682W WO0201913A1 WO 2002001913 A1 WO2002001913 A1 WO 2002001913A1 US 0120682 W US0120682 W US 0120682W WO 0201913 A1 WO0201913 A1 WO 0201913A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- speaker
- voice coil
- gap
- magnets
- magnet
- Prior art date
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
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/06—Loudspeakers
- H04R9/063—Loudspeakers using a plurality of acoustic drivers
-
- 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
- H04R2209/00—Details of transducers of the moving-coil, moving-strip, or moving-wire type covered by H04R9/00 but not provided for in any of its subgroups
- H04R2209/026—Transducers having separately controllable opposing diaphragms, e.g. for ring-tone and voice
Definitions
- the present invention relates to audio speakers and particularly to compact loud speakers.
- the number of applications to which compact speakers are put has grown substantially. This growth is partly due to the arrival of numerous new forms of consumer electronics and personal electronic music playing devices, many of which require or promote the use of accessory speakers for full volume delivery of high quality sound.
- the increased use of compact speakers has also been fueled by a general trend toward smaller bookshelf or desktop systems, rather than the cabinet work and larger speaker enclosures that had formed the benchmark for audio performance over many decades.
- a housing in which the performance of a compact speaker is further enhanced. It would also be desirable to devise such a speaker and housing, wherein the housing itself is adapted to be mounted in a cabinet, a wall space or other location as a unit, and to thereby adapt the mounting structure without extensive acoustic engineering or individualized design considerations.
- first and second annular magnets are arranged concentrically with each other and connected by a shunt structure at one end and a pole-defining structure at the other end to concentrate magnetic flux in a cylindrical gap.
- the shunt and the pole structure are also annular, and these are stacked such that the combined magnetic assembly has an opening extending centrally therethrough.
- the voice coil of a speaker rides in the cylindrical magnetic flux gap and its drive leads may be brought out behind the speaker, through the central opening.
- the diaphragm of the speaker may communicate tlirough the central opening with the volume of a tuned enclosure situated behind the speaker, thus allowing further control over total acoustics.
- the annular magnets are axially poled and of opposite polarity, separated by a cylindrical magnet gap between the two magnets.
- the construction may be applied to an assembly using two neodymium ring magnets, of 25 millimeter and 36 millimeter outer diameters, to achieve a total flux density over 1.4 Tesla in a one-inch voice coil gap with a total speaker weight below two ounces and a total energy of 100 milliWatt seconds in the gap.
- the mass of the costly neodymium is thus minimized while the available flux is efficiently focused in the gap and overall speaker performance excels.
- the magnet achieves this high energy in a very shallow gap, allowing the diaphragm to be strongly driven with small excursion.
- the central through opening facilitates lead handling, both during speaker assembly and during subsequent speaker installation.
- the opening may also be exploited to permits an effective level of either damped or resonant coupling to be achieved in a relatively shallow chamber.
- the chamber may be a ported enclosure that mounts in a flush or shallow panel or wall.
- Figure 1 illustrates a high performance magnet structure for the voice coil of a speaker in accordance with the present invention
- FIG. 1 A illustrates another embodiment of the invention
- Figure 2 illustrates field vectors in the magnetic structure of Figure 1 A
- Figure 3 is a graph of flux density across the gap of the structure of Figure 1A;
- Figures 4A and 4B are illustrations of flux paths and field lines, respectively, for the structure of Figure 1 A;
- Figures 5-8 illustrate features comparable to those of Figures 1A, 2, 3, and 4A, respectively, for a solid disk magnet structure of a first comparison construction
- Figures 9-12A, 12B illustrate features comparable to those of Figures 1A, 2, 3, 4A and 4B, respectively, for a solid disk magnet structure of a second comparison construction
- Figures 13-16A, 16B illustrate features comparable to those of Figures 1A, 2, 3, 4A and 4B, respectively, for a solid disk magnet structure of a third comparison construction.
- a speaker has a permanent magnet which, in the case of smaller high performance speakers, is preferably a rare earth magnet such as a neodymium magnet.
- the magnetic substructure also includes a shunt and pole piece structure that concentrate the field in a high flux gap where a cylindrical voice coil attached to the speaker diaphragm moves in accordance with an applied drive current signal.
- FIG 1 illustrates one embodiment of a speaker 10 in accordance with the present invention, showing its magnet structure 20 in detail, and its diaphragm D and voice coil VC schematically.
- the voice coil VC which may, for example, consist of a copper or other conductive winding on a cylindrical bobbin (formed, e.g., of Kapton sheet), rides in a magnetic gap G where the magnet structure 20 concentrates the magnetic flux.
- the diaphragm D is shown as a flat sheet extending across the region spanned by the cylindrical voice coil VC. Such a diaphragm is typically suspended about its outer periphery by a flexible rubber or polymer band attaching it to a frame (not shown).
- the diaphragm may be a domed or concave diaphragm spanning the coil diameter, or may be a sheet or cone positioned such that it extends primarily around the outside of the periphery of the voice coil to mount m a much larger frame.
- an additional annular band of flexible but dimensionally stiff material typically attaches to the voice coil or to the diaphragm in the region of the voice coil to maintain centering in the magnetic gap G.
- another flexible band typically attaches the diaphragm to the speaker frame.
- the magnetic structure 20 of the speaker assembly 10 includes first and second annular magnets 1, 2 that are positioned coaxially with each other and connected together by a shunt member 3 on one side of the magnets .
- the shunt member 3 rather than being a flat plate or sheet, is a shaped member, thinning toward its radially inner and radially outer edges. That is the sides 3a and 3b are beveled (or may be rounded), falling to a thinner body away from its middle portion.
- On the other side of the magnets 1, 2 are respective shaped pole pieces 4, 5.
- the inner and outer cylindrical magnets 1, 2 are positioned concentrically, with a small space between the outer periphery of the inner magnet and the inner wall of the outer magnet.
- the pole pieces 4, 5 each consist of or include an annular ring, and each sits on top of the respective magnet such that the separation between opposing faces of the two pole pieces forms the voice coil gap G.
- gap G is smaller than the underlying space between the two magnets, and is concentric therewith.
- the voice coil C has a diameter of about one inch and the inner magnet 1 has an external diameter of 24.5 millimeters with an eight millimeter central opening.
- the magnet 2 is positioned across a 1.5 millimeter gap and extends to 36 millimeters diameter.
- the pole pieces 4, 5 narrow the magnetic gap so that gap G is e.g., one millimeter.
- the pole pieces 4, 5 are thicker proximate to the gap G, and are tapered or thinned nearer to the radial inner and outer edges, respectively, of the assembly.
- Figure 1 A illustrates the magnetic structure of a prototype speaker in accordance with the present invention, showing a section taken along a radial plane through one side of the speaker magnets.
- the outer pole piece 5 possesses a projecting peripheral stand 5a.
- the edge of the diaphragm (for a flat diaphragm as shown in Figure 1) mayy attache to the stand 5a.
- the pole pieces are formed of a suitable material, e.g., iron or steel, and their shape serves to better utilize the flux, concentrating it in the voice coil gap, as well as to provide relief or clearance so that the diaphragm does not buzz.
- Figure 3 graphs the flux density achieved in the gap. As shown the dual concentric ring magnet structure delivers a flux density of 1.44 Tesla over a 2 millimeter by 1 millimeter gap; the total gap energy is 100 milliWatt seconds.
- Figure 2 illustrates the vectors in the magnetic structure of Figure 1A.
- Solid lines are inserted in the right hand side of the Figure to illustrate the metal/magnetic parts, and these are -dentified with numerals corresponding to the numerals of Figure 1.
- the magnets are poled N - S along the axis of the ring, and the outer ring magnet 2 is poled in the opposite direction from the inner one.
- the outer pole piece 5 includes the extending stub or band portion 5a at its outer periphery, which as illustrated in the succeeding detail Figures, affects the outer field lines.
- the pole and shunt structure applied to oppositely poled ring magnets more efficiently uses the available magnetic material to focus a high flux density in the gap G.
- the inner magnet 1 together with the keeper 3 and inner pole piece 4 are all annular elements defining a physical opening C through the center of the magnet assembly.
- Speaker input leads a,b pass through this central opening and connect to the voice coil VC.
- the representation of input drive lines is schematic only. A single lead may pass through the opening with a second lead grounded to metallic structure of the speaker.
- the leads a,b need not be wires as shown but make take other forms such as a flexible cable or microlithographically formed conductive elements in which a plastic sheet may encase and reinforce the metal conductor(s).
- the drive line may connect from the voice coil to a surface terminal pad structure on the diaphragm D, before connecting to the conductors that pass through the central aperture C. Other connection techniques known in the art may be employed.
- the drive or lead in conductors may pass directly through the aperture.
- This architecture thus eliminates the step of attaching the voice coil wires to a te ⁇ ninal strip or connecting pad stationed on the diaphragm or on the fabric centering support (of a cone). Since such intermediate connection has required delicate manipulations inside the speaker frame, this has been a time consuming fabrication step in the prior art.
- the opening C also provides air communication between the back and front of the speaker.
- the diaphragm D extends across the full face of the magnet assembly, its behavior may be affected by the stiffness of the air column through the opening, e.g.,into the cabinet or other space behind the magnet.
- this opening may be used to relieve such cabinet stiffness, and/or to vent or port sound from the cabinet interior.
- the magnet opening allows acoustic coupling to tailor the system response, and permits one to vent an enclosure to reduce air stiffness in smaller enclosures.
- Figures 4A and 4B plot the flux paths/field lines of the annular magnet structure and gap area of the device of Figure 1A, with continuous tone and with individual lines, respectively, indicating the very efficient use of the small magnet to define symmetrical flux paths while providing a ported magnet assembly.
- the dual ring structure had an 8 millimeter center hole allowing air coupling and wiring.
- the inner neodymium ring had a 24.5 millimeter outer diameter and a radial thickness of 8.25 millimeters, while the outer ring had a 36 millimeter outer diameter and a radial thickness of 4.25 millimeters, so that the space between the two concentric magnets was 1.5 millimeters wide.
- Both magnets were 3.5 millimeters thick, thus employing a volume of magnetic material equal to (1.47 + 1.45)cc, or 2.97cc, weighing 22.5 grams.
- the steel parts, the inner top plate, and outer top plate weighed 5 and 5.77 grams, respectively, with a total system weight of 48 grams, providing a flux density of 1.44 Tesla and a total energy of one hundred milliWatt seconds.
- FIG. 9 Another useful comparison is to a magnet structure as shown in Figure 9 that uses the same amount of neodymium magnet as the system of Figures 1-4.
- the magnet is a tall disk ten millimeters thick by 24.5 millimeters diameter weighing 12.55 grams.
- the top and bottom plate similar to the ones of the preceding Example but with a deeper shunt, bring the total system weight up to 48.5 grams.
- the flux density is increased to only 1.32 Tesla, but the magnet depth is increased to 15.5 millimeters making the structure somewhat less suitable for shallow enclosure.
- Figures 10-12B show the flux density, flux distribution, field line models and overall geometry of this example.
- Figure 13 By way of further example, if one were to seek the same energy in the gap as the system of Figures 1-5 but using a disk magnet, the construction would be as shown in Figure 13.
- the magnet has a thickness of twelve millimeters, and weighs forty grams, with the outer shell and top plate bringing the total system weight up, to over one hundred grams.
- Figures 15-16B show the flux density, flux distribution, field line models and overall geometry of this example. This construction results in a magnet depth of 18.5 millimeters, too deep to work with flat panel speakers. The increased magnet weight also renders this design also more costly than the double ring design of Figure 1.
- the double ring magnet design achieves a high flux density in a light weight practical way.
- the only conventional design of the same flux appears too deep, too heavy and too expensive.
- speakers of the invention efficiently concentrate the available flux in a narrow, shallow voice coil gap, but the center hole of the double ring design provides an opening through which the power wires are routed to supply the moving coil. This lowers speaker production costs by eliminating the delicate task of joining the drive lines to static coil te ⁇ ninals inside the speaker. It also achieves a smaller assembly size (since no space around the periphery need be allotted for cabling) and may simplify cabinet mounting methodology.
- the apertured magnet may also be employed to lower the stiffness of an enclosure in which the speaker mounts, or may be exploited for air coupling to an external tuned enclosure to damp or tune the response in combined speaker/enclosure systems.
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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)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2001270246A AU2001270246A1 (en) | 2000-06-27 | 2001-06-27 | Compact high performance speaker |
JP2002505553A JP2004502365A (en) | 2000-06-27 | 2001-06-27 | Small high-performance speaker |
EP01948816.2A EP1329130B1 (en) | 2000-06-27 | 2001-06-27 | Compact high performance speaker |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US21468900P | 2000-06-27 | 2000-06-27 | |
US60/214,689 | 2000-06-27 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2002001913A1 true WO2002001913A1 (en) | 2002-01-03 |
Family
ID=22800058
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2001/020682 WO2002001913A1 (en) | 2000-06-27 | 2001-06-27 | Compact high performance speaker |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP1329130B1 (en) |
JP (1) | JP2004502365A (en) |
CN (1) | CN1443433A (en) |
AU (1) | AU2001270246A1 (en) |
WO (1) | WO2002001913A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1420609A1 (en) * | 2001-07-23 | 2004-05-19 | Foster Electric Co., Ltd. | Flat speaker of full-face driving |
US7653208B2 (en) | 2004-09-09 | 2010-01-26 | Guenther Godehard A | Loudspeakers and systems |
US8588457B2 (en) | 1999-08-13 | 2013-11-19 | Dr. G Licensing, Llc | Low cost motor design for rare-earth-magnet loudspeakers |
US8929578B2 (en) | 2007-05-23 | 2015-01-06 | Dr. G Licensing, Llc | Loudspeaker and electronic devices incorporating same |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5802191A (en) | 1995-01-06 | 1998-09-01 | Guenther; Godehard A. | Loudspeakers, systems, and components thereof |
CN107517430B (en) * | 2016-06-17 | 2020-01-21 | 声电电子科技(惠州)有限公司 | Double-washer micro loudspeaker |
CN105979449B (en) * | 2016-06-24 | 2021-05-28 | 常州市武进晶丰电子有限公司 | Moving coil piezoelectric composite loudspeaker |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5446797A (en) * | 1992-07-17 | 1995-08-29 | Linaeum Corporation | Audio transducer with etched voice coil |
US5748760A (en) * | 1995-04-18 | 1998-05-05 | Harman International Industries, Inc. | Dual coil drive with multipurpose housing |
US5802191A (en) | 1995-01-06 | 1998-09-01 | Guenther; Godehard A. | Loudspeakers, systems, and components thereof |
US6208743B1 (en) * | 1996-03-21 | 2001-03-27 | Sennheiser Electronic Gmbh & Co. K.G. | Electrodynamic acoustic transducer with magnetic gap sealing |
US9927011B2 (en) | 2014-08-12 | 2018-03-27 | Kuroda Precision Industries Ltd. | Ball screw |
US10041198B2 (en) | 2009-08-11 | 2018-08-07 | Johns Manville | Curable fiberglass binder comprising salt of inorganic acid |
-
2001
- 2001-06-27 AU AU2001270246A patent/AU2001270246A1/en not_active Abandoned
- 2001-06-27 JP JP2002505553A patent/JP2004502365A/en not_active Withdrawn
- 2001-06-27 WO PCT/US2001/020682 patent/WO2002001913A1/en active Application Filing
- 2001-06-27 CN CN 01811725 patent/CN1443433A/en active Pending
- 2001-06-27 EP EP01948816.2A patent/EP1329130B1/en not_active Expired - Lifetime
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5446797A (en) * | 1992-07-17 | 1995-08-29 | Linaeum Corporation | Audio transducer with etched voice coil |
US5802191A (en) | 1995-01-06 | 1998-09-01 | Guenther; Godehard A. | Loudspeakers, systems, and components thereof |
US5748760A (en) * | 1995-04-18 | 1998-05-05 | Harman International Industries, Inc. | Dual coil drive with multipurpose housing |
US6208743B1 (en) * | 1996-03-21 | 2001-03-27 | Sennheiser Electronic Gmbh & Co. K.G. | Electrodynamic acoustic transducer with magnetic gap sealing |
US10041198B2 (en) | 2009-08-11 | 2018-08-07 | Johns Manville | Curable fiberglass binder comprising salt of inorganic acid |
US9927011B2 (en) | 2014-08-12 | 2018-03-27 | Kuroda Precision Industries Ltd. | Ball screw |
Non-Patent Citations (1)
Title |
---|
See also references of EP1329130A4 * |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8588457B2 (en) | 1999-08-13 | 2013-11-19 | Dr. G Licensing, Llc | Low cost motor design for rare-earth-magnet loudspeakers |
EP1420609A1 (en) * | 2001-07-23 | 2004-05-19 | Foster Electric Co., Ltd. | Flat speaker of full-face driving |
EP1420609A4 (en) * | 2001-07-23 | 2007-01-10 | Foster Electric Co Ltd | Flat speaker of full-face driving |
US7653208B2 (en) | 2004-09-09 | 2010-01-26 | Guenther Godehard A | Loudspeakers and systems |
US9060219B2 (en) | 2004-09-09 | 2015-06-16 | Dr. G Licensing, Llc | Loudspeakers and systems |
US8929578B2 (en) | 2007-05-23 | 2015-01-06 | Dr. G Licensing, Llc | Loudspeaker and electronic devices incorporating same |
Also Published As
Publication number | Publication date |
---|---|
EP1329130B1 (en) | 2015-02-18 |
CN1443433A (en) | 2003-09-17 |
EP1329130A1 (en) | 2003-07-23 |
EP1329130A4 (en) | 2007-03-21 |
AU2001270246A1 (en) | 2002-01-08 |
JP2004502365A (en) | 2004-01-22 |
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