AU745486B2

AU745486B2 - Loudspeakers

Info

Publication number: AU745486B2
Application number: AU88702/98A
Authority: AU
Inventors: Henry Azima; Graham Bank; Kieron Dunk; Neil Owen
Original assignee: New Transducers Ltd
Current assignee: NVF Tech Ltd
Priority date: 1997-09-04
Filing date: 1998-08-24
Publication date: 2002-03-21
Anticipated expiration: 2018-08-24
Also published as: BR9812163A; EP1010351A1; TW410525B; AU8870298A; CA2297041A1; AR013954A1; CN1269958A; JP2001515333A; IL134834A0; WO1999012387A1; KR20010023648A

Description

WO 99/12387 WO 9912387PCT/GB98/02532 TITLE: LOUDSPEAKERS DESCRI PTION TECHNICAL FIELD The invention relates to loudspeakers of the kind in which an acoustic output is produced by launching bending waves into an acoustic radiator comprising a resonant panel. Such loudspeakers are described in International patent application W097/09842 of New Transducers Limited.

It is an object of the present invention to provide a modular assembly comprising a resonant panel acoustic radiator f or use as a loudspeaker or as a drive unit for use in a loudspeaker.

DISCLOSURE OF INVENTION Accordingly the present invention provides an assembly comprising a resonant panel acoustic radiator, a body suspending the acoustic radiator, at least one vibration WO 99/12387 WO 9912387PCT/GB98/02532 2 exciter on the radiator to launch bending waves into the radiator to cause it to resonate to produce an acoustic output, and means on the body suspending the radiator for free movement relative thereto.

The body may take the place of a chassis in a conventional loudspeaker drive unit, although in the present invention the body is usually not required to be of the same degree of weight and rigidity as is required with a conventional pistonic drive unit. The body (hereinafter chassis) may be a lightweight frame-like structure.

The chassis may be such as to enclose the radiator panel. The chassis may be a tray-like member having a surrounding peripheral lip. The chassis may be of light weight and may, for example, be a plastics moulding. The chassis may be an open frame, or may be perforate.

Means may be provided for freely suspending the edges of the acoustic radiator on the chassis. The suspension may be such as to allow free movement of the acoustic radiator in directions normal to the plane of the radiator (it will usually be a flat plate) while preventing movement of the radiator in its plane. The suspension may comprise arms or links hinged at one end to the chassis and at the other end to the radiator for swinging movement about respective parallel axes at opposite ends of the arms or links. Such arms or links may be provided on all four sides of a generally rectangular radiator. The suspension arms or links on opposite sides of the radiator may be attached near to diagonally opposed corners of the 4~ WO 99/12387 PCT/GB98/02532 3 radiator. The connections of the arms or links to the radiator may be by means of resilient foam pads, e.g. of rubber or a rubber-like material, which are fixed to the radiator, e.g. by means of an adhesive, near to its corners and which receive hinge pins provided on the ends of the arms or links.

The chassis may be formed with a conduit in which services such as electrical input leads to the vibration exciter(s) may be located. The conduit may be in the form of a channel extending round the periphery of the chassis.

The chassis may be formed with means whereby it can be supported in position to form a loudspeaker or such that more than one of the assemblies can be linked together to form a larger loudspeaker unit. Thus the corners of the chassis may be formed with bores for receiving linking members comprising respective pegs which are frictionally received in the bores to hold two or more of the assemblies together edge-to-edge to form a large loudspeaker panel.

A linking member comprising two pegs may be used to join two adjacent modular assemblies, and a linking member comprising four pegs may join the corners of four adjacent modular assemblies.

The linking member may establish an electrical link between adjacent modular assemblies as well as providing the mechanical linkage. To provide an electrical connection, the pegs of each linking member may comprise outer and inner connectors and means electrically connecting the outer and inner connectors of one peg to the WO 99/12387 PCT/GB98/02532 4 outer and inner connectors of the other pegs of the linking member. To establish a serial electrical connection between the modular assemblies, the inner connector of one peg may be electrically connected to the outer connector of another peg of the linking member. For a parallel connection, the inner conductors of the pegs of the linking member may be electrically connected and the outer conductors of the pegs may be electrically connected.

The electrical signal may be carried between the modular assemblies by making two surfaces of the chassis or frame moulding electrically conductive. This may be achieved by embedding or otherwise applying electrical conductors in the channel, for example by printing, e.g. in the upper and lower surfaces of the peripheral lip of the chassis. A parallel pair of conductors may be provided.

Each conductor is preferably co-extensive with the surrounding peripheral lip of the chassis and may have a connector pad provided at each of its four corners. The connector pads are preferably received in the said bores at each corner of the chassis and which receive the linking members. Alternatively, two surfaces of the frame moulding can be made conductive during the moulding process, e.g. by advanced injection moulding techniques. In either case the conductive surfaces of the frame moulding may provide a busbar for electrical connectivity between each of the following pairs, namely adjacent resonant panel acoustic radiators, exciter(s) and frame, and each two resonant panel acoustic radiator assembly to the outside world.

S- WO 99/12387 WO 99/ 2387PCT/GB98/02532 The resonant panel acoustic radiator may comprise a member having capability to sustain and propagate input vibrational energy by bending waves in a least one operative area extending transversely of thickness to have resonant mode vibration components distributed over said at least one area and have predetermined preferential locations or sites within said area for vibration exciter means and having an exciter mounted on said member at one of said locations or sites to vibrate the member to cause it to resonate forming an acoustic radiator which provides an acoustic output when resonating.

The or each vibration exciter may be of the kind described in our International patent application W098.31188, which describes a vibration exciter which can be freely or resiliently suspended on a support, e.g. the body or chassis of the present invention.

BRIEF DESCRIPTION OF DRAWINGS The invention is diagrammatically illustrated, by way of example, in the accompanying drawings, in which:- Figure 1 is a perspective cross-sectional view of a modular loudspeaker drive unit; Figure 2 is an exploded perspective view of the modular assembly of Figure 1; Figure 3 is a perspective view showing the interior face of a basket or chassis for the modular assembly of Figure 1, and Figure 4 is a perspective view of a resonant acoustic radiator panel for the modular assembly of Figure 1; WO 99/12387 WO 9912387PCT/GB98/02532 6 Figure 5 is a perspective view of two interconnected modular assemblies; Figure 6 is a perspective view of four interconnected modular assemblies; Figure 7 is an enlarged scrap perspective view of a linking member interconnecting two modular assemblies; Figures 8 is an enlarged scrap perspective view of a linking member and a corner of one modular assembly; Figure 9 is an enlarged scrap perspective view of a linking member interconnecting four modular assemblies; Figure 10 is an enlarged scrap perspective view of a linking member and the corners of two modular assemblies; Figure lla,llb,llc are respective perspective views of parallel and serial linking members; Figure 12 is an exploded perspective view of the modular assembly of Figure 1 with the addition of a pair of busbars; Figure 13 is a perspective view of a connector pad, and Figure 14 is a partial cross-section through a pair of modular assemblies and a linking member connecting them together.

BEST MODES FOR CARRYING OUT THE INVENTION Figures 1 to 4 illustrate a flat generally rectangular modular loudspeaker drive unit assembly comprising a generally rectangular stiff lightweight resonant acoustic radiator panel e.g. of the kind described in International patent application W097/09842 mounted in a WO 99/12387 PCT/GB98/02532 7 surrounding generally rectangular body in the form of a chassis or basket with a pair of vibration exciters (4) mounted on the panel to launch bending waves into the panel to cause it to resonate to provide an acoustic output.

The chassis encloses the radiator panel and is formed with a surrounding outwardly facing conduit (14) defined between outwardly projecting flanges (11) in which services such as electrical input leads to the vibration exciters can be located. The conduit (14) is thus in the form of a channel extending round the periphery of the chassis (3) Figures 1 and 2 also illustrate a means for freely suspending the acoustic radiator on the chassis by its edges. The suspension comprises arms or links (8) hinged at one end to the chassis and at the other end to the radiator for swinging movement about respective parallel axes at opposite ends of the arms or links (8) The connections of the arms or links to the radiator is by means of resilient foam pads (10) each formed with a bore which receive hinge pins provided on one end of each of the arms or links The other end of each arm or link is formed with a cylindrical boss (24) received in a corresponding aperture (29) on the chassis The suspension is such as to allow free movement of the acoustic radiator in directions normal to the plane while preventing movement of the radiator in its plane.

WO 99/12387 PCT/GB98/02532 8 As shown in Figure 2, a pair of inertial electrodynamic vibration exciters are coupled to the radiator to launch bending wave vibration into the radiator. The exciters are suspended on the chassis such that their motion normal to the plane of the radiator is unimpeded and to prevent movement of the exciters in the plane of the radiator whereby centring of the relatively movable parts of the exciters is ensured. This exciter suspension is the subject of International patent application W098/31188.

This suspension resembles, at least in function, the spider commonly found in the drive units of conventional pistonic loudspeakers, and is in the form of a disc-like plate having an inner portion attached to the exciter and an outer portion attached to the chassis, the inner and outer portions being separated such that the one can move normally with respect to the other and so that relative movement in the plane of the disc-like plate is prevented.

This is achieved by forming the disc with circumferential and radial slits (30,32) respectively to form a pair of curved limbs (33) the free ends (31) of which are attached to the chassis. For this purpose the chassis is formed with a plate-like exciter locating portion (23) formed with opposed apertures (25) which align with and surround the respective exciters and to which portion the free ends (31) of the limbs (33) are attached. A heat sink is attached to each exciter over the top of the plate to assist in cooling the exciters 1 WO 99/12387 PCT/GB98/02532 9 during use.

Figure 3 shows the interior face of the basket or chassis The chassis is a tray-like member comprising a perforate plate-like member (34) having an upstanding rim (35) which carries the surrounding pair of outwardly extending flanges (11) which define the conduit The chassis is lightweight and may, for example, be a plastics moulding.

Figure 4 illustrates the positions of the resilient foam pads (10) on the acoustic radiator The foam pads comprise bores (26) to receive hinge pins provided on the ends of the arms or links of the means for suspending the edges of the acoustic radiator on the chassis The foam pads (10) are positioned on all four sides of the radiator and the foam pads (10) on opposite sides of the radiator are attached near to diagonally opposed corners of the radiator The resilient foam pads (10) which may be of rubber or a rubber-like material, are fixed to the radiator e.g.

by means of an adhesive.

Figures 5 and 6 illustrate respectively the interconnection of the chassis of two and four of the modular assemblies of Figures 1 to 4. To this end the corners of the chassis are formed with bores (15) for receiving linking members (16,18) comprising respective pegs (17) which are frictionally received in the bores to hold the two assemblies together edge-to-edge to form a large loudspeaker panel. The linking member (16) comprises WO 99/12387 PCT/GB98/02532 two parallel pegs and is used to hold two modular assemblies together. The linking member (18) comprises four parallel pegs arranged in a square formation. A combination of the linking members (16,18) may be used to hold four assemblies together.

Figure 7 illustrates the detail of the linking member (16) of Figure 5 which comprises two parallel pegs interconnected by a web or arm The two pegs are frictionally received in the bores to interconnect two modular assemblies of the kind shown in Figures 1 to 4.

Figures 8 to 10 illustrate the detail of the linking member (18) of Figure 6. As can best be seen in Figure 8, the linking member (18) comprises four pegs (17) interconnected by a cruciform web The web (28) comprises a generally rectangular central body (38) and four arms (39) which extend from the four corners of the rectangular body Each peg (17) is frictionally received in a bore (15) at the corner of the chassis of a modular assembly of Figures 1 to 4.

Figure 9 illustrates how four modular assemblies (1) are interconnected by a linking member (18) which has each of its pegs (17) frictionally received in bores (15) at the corners of the modular assemblies (1) Figure 10 illustrates the details of the bores which frictionally receive the pegs The bores are generally cylindrical with a rectangular groove (40) to receive the arm (39) of the web (28) which interconnects

I;

L

WO 99/12387 WO 99/ 2387PCT/GB98/02532 the pegs (17).

Figures lla,llb and 11c are perspective views of series and parallel connected linking member which are used to establish an electrical link between adjacent acoustic radiators. As can be seen in Figure 11c, the linking member (16) comprises two pegs (171,17"1) each of which comprise an outer electrical connector (20) and an inner electrical connector (19) arranged in a co-axial configuration.

In Figure 11a, a serial electrical connection between the assemblies (not shown) is established by electrically connecting via conductor wires (21) the inner connectors (19,19') of each peg (171,17"1) to the outer connectors (20,20') of the other peg In Figure 1lb, a parallel connection is established by electrically connecting via conductor wires (21) the inner conductors (19,19') of each peg (171,17") and by electrically connecting via conductor wires (21) the outer conductors (20,20') of each peg (171,17"1).

Figure 12 illustrates the modular assembly with an opposed pair of conductor rails or busbars (12,13), which are mounted on or located in or embedded in the chassis to surround the chassis. One conductor (12) may be positively charged and the other conductor (13) may be negatively polarised to carry the electrical signal between adjacent assemblies The conductors (12,13) are co-extensive with the peripheral lip (11) of the chassis and have connector pads (22) at each corner and U WO 99/12387 WO 9912387PCT/GB98/02532 12 which pads are arranged to f it into the bores (15) at each corner of the chassis for electrical contact with the linking members illustrated in Figures lla,llb and lic above.

Figure 13 illustrates the detail of a connector pad (22) at the corner of a conductor (12) The connector pad (22) comprises a circular ring (36) and a link (37), attaching the ring (36) to the connector pad (22).

As shown in Figure 14, the busbars (12,13) are electrically connected to the electrical connections of the linking members (16,18) by means of screws (41) which engage threaded inserts (42) in the linking members to hold the linking members in the bores (15) in the assemblies .The screws (41) thus ensure both the mechanical connection of the assemblies and the electrical connections between the assemblies.

INDUSTRIAL APPLICABILITY The invention thus provides a simple manner of adapting resonant panel acoustic radiators for mass production and for electrically connecting interlinked acoustic radiators.

M

Claims

2. An assembly according to claim 1 wherein the body has corners form-ed with bores, and linking members are provided comprising respective pegs which are :adapted to be received in the bores to hold a plurality of the assemblies together edge-to- edge. aapte An assembly according to claim 2, wherein the linking members are aatdto establish an electrical link between adjacent assemblies. 20 4. An assembly according to claim 3, wherein each linking member *000 comprises two or more pegs, each of which comprises connector pairs and means for electrically connecting the connector pairs of one peg to the connector pairs of the other 0 pegs. 0 0 25 5. An asebyaccording to claim 4, weinthe connector pisare concentric.
6. An assembly according to claim 5, wherein a serial electrical connection between the acoustic radiators is established by electrically connecting the inner connectors of each peg to the outer connectors of the other pegs.
7. An assembly according to claim 5, wherein a parallel electrical connection is established by electrically connecting the inner conductors of each peg R44' together and by electrically connecting the outer conductors of each peg together. [R:\LIBOO]05240.doc:kxa 14
8. An assembly according to any one of claims 3 to 7, wherein electrical signals are carried between assemblies by conductive members on the respective bodies.
9. An assembly according to claim 8, wherein the body is moulded and in that surfaces of the body are rendered electrically conductive during moulding. An assembly according to claim 8, wherein electrical conductors are embedded in the upper and lower surfaces of the peripheral lip of the body.
11. An assembly according to claim 9, wherein conductors have opposite polarity. a
12. An assembly according to claim 10 or claim 11, wherein each conductor 15 is the same shape as the surrounding peripheral lip of the body.
13. An assembly according to any one of claims 10 to 12, wherein each conductor has a connector pad at each corner. 20 14. An assembly according to claim 13, wherein the connector pads are adapted to be received by the bores at each corner of the body.
15. An assembly according to any preceding claim, wherein the body is formned with a conduit in which electrical services are located.
16. An assembly according to claim 15, wherein the conduit is in the form of a channel extending round the periphery of the body.
17. An assembly according to any preceding claim, wherein means suspends the vibration exciter on the body for free movement relative thereto.
18. A loudspeaker comprising an assembly as claimed in any preceding claim. [R:\LIB3OO]05240.doc:kxa
19. An assembly substantially as described herein in relation to the accompanying drawings. DATED this Twenty-second Day of January, 2002 New Transducers Limited Patent Attorneys for the Applicant SPRUSON FERGUSON [R:\LIBOO]05240.doc:kxa