WO2019229726A1

WO2019229726A1 - Speaker grilles and speakers incorporating same

Info

Publication number: WO2019229726A1
Application number: PCT/IB2019/054568
Authority: WO
Inventors: Eddy Rinna; Hung Yan Ho
Original assignee: Gp Acoustics International Limited
Priority date: 2018-06-01
Filing date: 2019-06-03
Publication date: 2019-12-05

Abstract

A composite speaker grille comprising a substrate member and a taut microfabric layer extending over a front surface of the substrate member to form an outward-facing surface of the grille is disclosed, wherein the substrate member is formed of a molded synthetic material of high rigidity and is divided into an acoustic region and a non-acoustic region, wherein one driver aperture or a plurality of driver apertures is formed on the substrate member to form the acoustic region; and wherein the microfabric layer includes an acoustic portion which is perforated and covers the acoustic region of the substrate member and a non-acoustic portion which is non-perforated and covers the non-acoustics region of the substrate member.

Description

SPEAKER GRILLES AND SPEAKERS INCORPORATING SAME

Field

[0001 ] The present disclosure relates to speaker grilles and speakers incorporating speaker grilles.

Disclosure

[0002] Speaker grilles are used to cover a front surface of speakers for aesthetic reasons, for protection or for other reasons. Speaker grilles require careful acoustic designs to mitigate adverse influence to the sound quality of speakers, especially speakers of high-fidelity grades. A speaker herein means an audio apparatus comprising a hollow housing which forms an acoustic box and one acoustic driver unit or a plurality of acoustic driver units mounted on the housing. The acoustic driver (“driver” in short) is to be driven by electrical signals which are arranged as a train of audio input signals. When the acoustic driver is driven by a train of audio input signals, the electromechanical arrangements of the acoustic driver is to convert the audio input signals into mechanical vibrations of a diaphragm of the driver, whereby audible signals are propagated from the speaker. A typical acoustic driver has an axial direction which defines a main direction of sound propagation. The axial direction is usually a forward direction. A speaker grille is an outer panel or the outermost panel of a speaker which is mounted forward of the driver(s) and typically covers a front surface of the speaker housing. The front surface of the speaker housing is typically an outward-facing surface on a front panel on which a driver aperture or a plurality of driver apertures is formed so that a driver or a plurality of drivers can be mounted. The front panel of a speaker typically has a width that is larger than the width of the driver or the largest driver. The driver aperture typically has a clearance which is slightly larger than the dimensions of the sound- propagating diaphragm so that the driver is mounted on the speaker box in a closely fitted manner, and such that the sound-propagating vibrations of the diaphragm are unhindered or substantially unhindered. A speaker housing is typically made of wood, metal, plastics or composite materials.

[0003] Conventional speaker grilles are either metal grilles formed of metal or MDF (medium density fiber) grilles formed of medium density fiber. Metal grilles have a cold feel and MDF grilles are somewhat bulky. Improvements in speaker grilles are desired.

[0004] A speaker grille is typically disposed forward of the acoustic paths of the drivers of the speaker. To mitigate obstruction or distortion of sounds travelling out of the speaker box and along the acoustic paths, the portion(s) of the speaker grille which is/are on the acoustic paths is/are formed as an acoustic region. An acoustic region herein means a region which is transmissive or transparent to sound forwardly propagated by the associated driver which is immediately behind the acoustic region. An acoustic region on a grille comprises an acoustic aperture which is aligned with an associated acoustic driver which is proximal to and immediately behind the acoustic aperture. A driver aperture on a speaker grille typically has an aperture size that is slightly larger than the size of a corresponding speaker driver to cater for sound diffusion properties of a typical speaker driver. An acoustic aperture on the grille does not need to be a totally empty aperture, but can be an effective acoustic aperture which permits through passage of sound propagated from the associated driver with minimal obstruction, attenuation or distortion. The acoustic aperture is also referred to as a driver aperture on the grille where convenient.

[0005] To maximize spatial and energy efficiency of a speaker, the width of the largest driver of a high-end or high-quality audio speaker is almost the same as (that is, comparable or slightly less than) the width of the speaker box. It is a typical design constraint that the width of a speaker grille is comparable to or slightly less than the width of the speaker box to be aesthetically pleasing and to have a good spatial and energy efficiency. However, such a design constraint means that the boundary of the largest driver aperture is very close to the outer lateral boundary of the grille which defines the width of the grille, leaving a very thin margin between the driver aperture of a grille and the grille boundary. As a result, the speaker grille is relatively thin and weak at the lateral borders or corners where a large driver aperture is present. The weakness due to the thin margins means that the speaker grille is very susceptible and vulnerable to breakage or deformation, for example, twisted deformation when a twisting torque is applied at its far or diagonal corners.

[0006] A composite speaker grille comprising a laminated acoustic fabric layer is disclosed. The speaker grille comprises a substrate member and a fabric layer which is surface-mounted on the substrate member. The substrate member comprises a front surface, a rear surface and a peripheral wall interconnecting the front and rear surfaces which cooperate to define a grille panel. The front surface is outward-facing and is referred to as a main surface. The substrate member is formed from a rigid material and has the form of a sheet or a plate such that the width of the front and rear surfaces is substantially (say more than 20 times, more than 30 times, more than 40 times, or a range formed by any of the aforesaid values) larger than its thickness which is defined by the thickness of the peripheral wall in the forward direction. The substrate member is formed from a highly rigid and brittle material such as Bakelite and has a highly rigid front and rear surface. A highly rigid front and rear surface herein is one which is not deformable by application of a manual force in a direction orthogonal to the surface. [0007] The substrate member extends in a longitudinal direction to define the length of the grille and extends in a lateral direction orthogonal to the longitudinal direction to define the width of the grille. Where there is a plurality of drivers, the drivers may be distributed in a lengthwise or widthwise direction without loss of generality. The substrate member has an inherent rigidity to function as a skeleton which defines the overall shape and dimensions of the speaker grille. However, the formation of a large driver aperture on the main surface, which is also a major surface, of the substrate member impairs the structurally integrity of the substrate member in the longitudinal and / or diagonal direction. The large driver aperture extends across a major portion of the width of the substrate member and has a very small margin left between the driver aperture and the lateral sides of the speaker grille or between the driver aperture and three or four lateral sides of the speaker grille. A very small margin herein means the margin is less than 15%, 14%, 13%, 12%, 10%, 1 1 %, 9% or a range formed by any of the aforesaid values of the width of the substrate member. The small margins between the largest driver aperture and the boundary of the substrate member means that the substrate member has a large space occupancy ratio (space ratio in short) at the region of the large driver aperture, with an empty space region defined by the driver aperture surrounded by a solid-state portion formed of the substrate material. The small margins between the driver aperture and the outer boundary of the substrate members means that the bare substrate member is very prone to deformation about its diagonal or diagonal axis when a twisting torque is applied on diagonal corners of the bare substrate member. A bare substrate member herein means a substrate member which is not surface-mounted with a fabric layer.

[0008] The composite speaker grille comprises an acoustic region which is defined by the acoustic aperture and a non-acoustic region which is the regions outside the acoustic aperture. An acoustic region is designed and provided to permit passage of sound through the grille with reduced or minimal blocking, obstruction or distortion. An acoustic fabric herein is a fabric which permits good quality or high-fidelity passage of sound and which can be used as a speaker grille material. Good quality herein means high-fidelity or near-high fidelity grade. Microfabrics are an example of high- fidelity grade of acoustic fabrics. A non-acoustic region prohibits passage of sound so that a sound to be propagated from the speaker drivers has to propagate through the acoustic regions. An acoustic aperture is defined by the boundary of the acoustic aperture, which is also an internal boundary on the substrate member. The space-ratio or space-occupancy ration of an acoustic aperture is measured with reference to the longitudinal and lateral boundary of the substrate member which defines the acoustic aperture. [0009] The speaker grille comprises one acoustic portion or a plurality of acoustic portions which forms the acoustic region. Each acoustic portion defines an acoustic region and has a driver aperture and a microfabric screen spanning across the driver aperture. The microfabric screen is a perforated and taut microfabric layer which spans across the driver aperture. The driver aperture is to align with a speaker driver on a speaker main unit on which the grille is or to be attached. In some embodiments, the speaker driver has a diffusing sound transmission surface and the driver aperture has a driver aperture size which is slightly larger than the speaker driver size to accommodate path expansion due to sound diffusion. The driver aperture or the plurality driver apertures is defined on the laminate composite. The laminate composite is a main skeleton of the composite speaker grille which is to support the acoustic portions and for attachment to a speaker main unit.

[0010] The microfabric layer comprises an acoustic region and a non-acoustic region. The acoustic region of the microfabric layer comprises one or a plurality of acoustic portions wherein each acoustic portion is a perforated microfabric portions spanning across the driver aperture. An acoustic portion is surrounded and supported by a non-acoustic portion. A non-acoustic portion of the microfabric layer is a taut microfabric portion, preferably non-perforated. The microfabric layer is mounted taut on a laminate composite. The laminate composite (or composite laminate) comprises a plurality of plastic plates which are laminated together to form a composite plate group. The composite plate group may comprise sheets or plates selected from thermoset plastics, resins such epoxy resin, glass-reinforced epoxy or their combination.

[001 1 ] There is provided a composite speaker grille comprising a base plate member and a taut microfabric layer extending over a front surface of the base plate member to form an outward facing main surface of the grille. The microfabric layer is surface-mounted on the substrate member which is in an example form of a base plate member. The microfabric layer is surface- mounted on the base plate member, with strengthening tensions applied in the course of surface mounting to provide a strengthening tension on the substrate member, so that the substrate member, especially the portion of the substrate member having a large space occupancy rate, is more resistant to twisted deformation. Twisted deformation herein is a measure of deformation when corners of the substrate member on opposite ends of a diagonal of the substrate member are subject to a twisting torque. The extent of deformation may be measured in terms of angles as angular deformation or in terms of amplitude as amplitude deformation. Angular deformation is measured as the angle between the sides between which the diagonal extends. The sides are parallel and aligned when no twisting torque is applied. Amplitude measurement is measured as the distance between the off set between the ends of the sides. The driver aperture creates a weakness on the substrate member and the weakness transforms the substrate member into one which is resiliently deformable along the diagonal axis. The microfabric layer strengthens the substrate member while retaining resilience about the diagonal axis. The microfabric layer strengthens the substrate member by mitigating the angular extent of twisted deformation by 10%, 15%, 20%, 25%, or a range or any ranges selected from the aforesaid values. The surface- mounted microfabric layer provides strengthening tensions in the lateral direction, the longitudinal direction and/or the diagonal directions to reinforce the substrate member, especially against twisting torques.

[0012] The composite speaker grille makes possible a sleek grille design without having to use a metal grille to attain a good strength against shear distortion.

[0013] The base plate member may be a composite plate group comprising a plurality of thermoset plastic boards such as a first and second Bakelite boards which are bonded together.

[0014] The composite plate group may comprise additional intermediate layers. The additional intermediate layers may comprise PU (polyurethane) or FR4 or other sheet materials, for example, thermoset plastic materials. FR4 is a glass-reinforced epoxy laminate material composed of woven fiberglass cloth with an epoxy resin binder. The laminate is a high-pressure thermoset plastic.

[0015] A composite plate group having a multi-layer bonded structure provides enhanced twisting resistance as well as providing a small resilience to allow a small degree of bending.

[0016] The example base plate member is formed of a molded synthetic material of high rigidity and is divided into an acoustic region and a non-acoustic region.

[0017] One driver aperture or a plurality of driver apertures is formed on the base plate member to form the acoustic region.

[0018] The microfabric layer includes an acoustic portion which is perforated and covers the acoustic region of the base plate member and a non-acoustic portion which is non-perforated and covers the non-acoustics region of the base plate member. The acoustic portion is a perforated microfabric layer having a thickness which is substantially smaller than the maximum thickness of the grille.

[0019] The example grille is a substantially planar member having a substantially uniform thickness except at the acoustic portions. [0020] The base plate member has a longitudinal axis which extends to define a longitudinal direction, and wherein the microfabric layer extends taut along the longitudinal direction and along the acoustic region.

[0021 ] The base plate member has a transversal axis which extends to define a transversal direction orthogonal to the longitudinal direction, and wherein the microfabric layer extends taut along the transversal direction and along the acoustic region.

[0022] An example base plate member has a maximum space ratio of 70% or higher in the longitudinal direction and/or in the transversal direction, including 75% or higher, 80% or higher, 85% or higher, and a range or ranges defined by any of the aforesaid values.

[0023] An example acoustic portion has a space ratio of 60% or higher, including 61 % or higher, 62% or higher, 63% or higher, 64% or higher, 65% or higher, 66% or higher, 67% or higher, 68% or higher, 69% or higher, or 70% or higher.

[0024] An example driver aperture is defined to center about a driver axis, wherein the driver axis is orthogonal or at an angle to the outward facing surface of the grille, and the acoustic portion is taut in radial directions with respect to the driver axis.

[0025] An example grille has a pair of lateral edges defined by a pair of longitudinal sides, wherein the grille at a longitudinal location has a width which is defined by separation distance between the lateral edges in a transversal direction orthogonal to the longitudinal sides.

[0026] An example backplate has a minimum width portion at a longitudinal location where the driver aperture has a maximum lateral extent.

[0027] An example minimum width is 20% or less of the width of the grille, including 19% or less, 18% or less, 17% or less, 16% or less, 15% or more, or a range or ranges having limits set by any of the aforesaid values.

[0028] An example base plate member has a minimum width at a longitudinal location and where the driver aperture has a maximum lateral extent.

[0029] An example base plate member has a minimum edge to driver aperture separation distance at the longitudinal location.

[0030] An example minimum edge to driver aperture separation distance is 10% or less of the width of the base plate member, including 9% or less, 8% or less, 7.5% or less, 7% or less, 6.5% or less, 6% or more, or between 1 cm and 1 .5cm, or a range or ranges having limits set by any of the aforesaid values. [0031 ] A plurality of driver apertures is formed on an example base plate member and the base plate member has a minimum inter-driver aperture separation.

[0032] An example minimum inter-driver aperture separation is 10% or less of the width of the base plate member, including 9% or less, 8% or less, 7.5% or less, 7% or less, 6.5% or less, 6% or less, 5.5% or less, 5% or more, or between 0.8cm and 1 .5cm, or a range or ranges having limits set by any of the aforesaid values.

[0033] An example grille has an inward-facing surface which is a back surface that is opposite facing to the outward facing surface, wherein the perforated microfabric acoustic portion of the microfabric layer is at a forward separation distance from the back surface; and wherein forward separation distance is comparable to the thickness of the base plate member or is at 8.5mm or less, including 8mm or less, 7mm or less, 6mm or less, 5mm or more, or a range or ranges having limits set by any of the aforesaid values.

[0034] An example base plate member has a substantially uniform thickness and the thickness of the microfabric layer is substantially smaller than the thickness of the base plate member; and wherein the base plate member has a thickness of 4mm or less, including 3.5mm or less, 3mm or less, 2.5mm or less, 2mm or more, or a range or ranges having limits set by any of the aforesaid values.

[0035] An example base plate member comprises a thermoset hard plastic plate, such as a Bakelite plate.

[0036] An example base plate member is a composite plate member comprising a plurality of thermoset hard plastic plates physically joined together.

[0037] An example base plate member comprises a first plate member which is a forward-facing plate having a forward -facing surface and a second plate member which is a rearward-facing plate having a rearward-facing surface, wherein each one of the forward-facing plate and the rearward facing plate is a thermoset hard plastic plate such as a Bakelite plate; and wherein the forward facing plate and the rearward-facing plate are physically joined by hot melt.

[0038] A plurality of magnet slabs each having a pair of opposite facing magnetic surfaces of opposite magnetic properties is embedded inside the second plate member of an example composite plate group. The magnet slabs may be distributed along lateral sides of the grille, and wherein the magnet slabs are disposed such that that magnetic surfaces are exposed on the rearward-facing surface of the second plate member. [0039] An example base plate member has a rearward-facing surface which is to face a speaker main body when attached to a speaker; wherein the grille comprises an attachment means having an attachment surface for self-attachment to the speaker main body; and wherein the attachment surface is flush or almost flush with the inward facing surface.

[0040] An example grille has an inward-facing surface which is to oppositely face and in abutment with a speaker main body when attached to a speaker; wherein the grille comprises an attachment means having an attachment surface for self-attachment to the speaker main body; and wherein the attachment means is distributed on the inward-facing surface and is flush therewith.

[0041 ] An example base plate member has a hard surface and the base plate member is twist- deformable about a diagonal line of the base plate member and wherein the taut microfabric layer increases twist-deformation resistance of the base plate member by at least 20%.

[0042] An example microfabric layer has a thickness of a thickness of 1 2mm or less, including 1 .1 mm or less, 1 .0mm or less, 0.9mm or less, 0.8mm or less, 0.7mm or less, 0.6mm or more, or a range or ranges having limits set by any of the aforesaid values.

[0043] The perforated microfabric acoustic portion of the microfabric layer may be a taut planar layer.

[0044] An example speaker grill optionally comprises a plurality of sound transmission portions and each sound transmission portion corresponds to an acoustic portion of the microfabric layer; and wherein adjacent acoustic portions are separated by a non-acoustic portion.

[0045] The microfabric layer may be held taut on the base plate member by a hot-melt glue film.

[0046] The example microfabric layer may have a suede feel, look and/or texture.

[0047] A method of forming a speaker grille is disclosed. The method comprises:

- Forming a composite base plate member, the composite base plate member comprising one driver aperture of a plurality of driver apertures; and

- Mounting a microfabric layer on the composite base plate member, the microfabric layer comprising acoustic regions which are perforated for sound transmission; wherein the acoustic regions are mounted taut and extend across the driver aperture or driver apertures.

[0048] The acoustic region of the microfabric layer is perforated and may have a space ratio of 55% or more, including 60% or more, 65% or more. [0049] The method may comprise forming self-attachment means on an inward facing surface of the speaker grille, the inward facing surface being in abutment with a speaker main body during use when the grille is attached to the speaker main body.

[0050] The method may comprise forming perforations on the acoustic regions by laser.

[0051 ] The method may comprise forming perforations of uniform size and separation.

[0052] The method may comprise forming a PU layer or a microfabric layer on an or the inward facing surface of the speaker grille.

[0053] A speaker comprising a grille according to any claim or a grille made according to any claim is disclosed.

Figures

[0054] The present disclosure will be described and/or illustrated with reference to the accompanying Figures in which:

Figures 1 and 1 A are perspective views of an example speaker according to the disclosure, Figure 1 B is a partial perspective view of another example speaker according to the disclosure, Figure 2 is a perspective view of an example speaker grille,

Figure 2A is an enlarged view of a portion of the example speaker grille of Figure 2,

Figure 3A is a plan view of an example speaker grille of Figure 2,

Figure 3A1 shows dimensions of the example speaker grille of Figure 3A with two of the driver apertures shown in dotted lines,

Figure 3A2 is a plan view of Figure 3A showing additional dimensions and a section line A-A,

Figure 3B is an enlarged cross-sectional view of Figure 3A2 along the section line A-A,

Figures 3C and 3D are, respectively, enlarged cross-sectional views of the portions C and D of Figure 3B,

Figure 3E is partial enlarged view of the example grille of Figure 3A showing an enlarged view of an acoustic portion,

Figures 3G and 3F are, respectively, perspective views from front (portion) and rear of the grille of Figure 3E,

Figure 4A is an exploded view of the example grille of Figure 3A, Figures 5 and 5A are enlarged cross-sectional views of another example speaker grille, and Figure 6 is an exploded view of the example grille of Figure 5.

Description

[0055] An example speaker 10 depicted in Figure 1 is a high-fidelity grade speaker comprising a speaker main unit 12 and a speaker grille 100. The speaker grille 100 is detachably attached to the speaker main unit and is detachable from the speaker main unit, as depicted in Figure 1 A. The example speaker main unit 12 comprises a speaker housing in the form of a speaker box 13 having a front panel defining a front surface 13A and a side panel defining a lateral surface 13B. A plurality of speaker drivers 14A, 14B, 14C is mounted on the front panel and each speaker driver has a forward-facing driver surface which is to deliver high-quality reproduced sound forward of the speaker box to reach an audience in front of the speaker. The forward-facing driver surface is a sound delivery surface which usually comprises a diaphragm which is to vibrate back and forth to transmit sound along a sound transmission path. Each driver has a driver axis which defines a main direction along which the reproduced sound is to be transmitted. The main direction in the example is a forward direction orthogonal to the front surface 13A but other directions are of course possible. For typical drivers, the driver axis is also the center axis of the driver. The sound delivery surface of a speaker driver is usually a sound diffusion surface and the reproduced sound is delivered forwardly and within an angular range to define a sound cone forward of the speaker.

[0056] An example grille 100 comprises an outward-facing side having an outward-facing surface 102 and an inward facing side having an inward-facing surface 104 which is opposite facing to the outward-facing surface, as depicted in Figures 2 and 2A. The inward-facing surface is a surface which is to oppositely face and in abutment with a speaker main body and the outward-facing surface is a main surface which faces away from the speaker main body during use.

[0057] The example grille 100 comprises a rigid main body and a microfabric layer which is surface-mounted on the main body to form the outward-facing surface 102 of the grille. The grille comprises acoustic regions and non-acoustic regions. An acoustic region is a region of the grille which is immediately forward of a driver and on the sound transmission path of the speaker. A non-acoustic region is a region of the grille which is forward of a driver but outside the sound transmission path.

[0058] Each acoustic region of the grille comprises a driver aperture on the main body and the driver aperture is spanned by a taut and perforated microfabric portion. The example grille 100 of Figure 2 comprises an example plurality of three acoustic regions and each acoustic region is an acoustic portion which is located and sized to correspond to a corresponding speaker driver on the speaker main unit. The example speaker 10 comprises an example plurality of three drivers on the speaker main unit and the example grille 100 has three acoustic portions to correspond to the three example drivers. Each of the example driver is a 6-inch or 15-cm diameter driver unit having a sound transmission and diffusion surface. To mitigate block of sound transmission, each driver aperture on the main body of the grille has a footprint defining an aperture which is slightly larger than the size of the forward -facing driver surface of the driver. For example, the example driver aperture has a diameter of 175mm, which is about 10% larger than the diameter of the speaker driver.

[0059] The example grille has a transversal extent which is defined by or between a pair of longitudinal edges on the longitudinal sides, and a longitudinal extent which is defined by or between a pair of transversal edges on the lateral sides. The example grille is elongate and has a longitudinal axis which is also a center axis dividing the grille into two laterally symmetrical halves. The longitudinal extent is measured in a direction along the longitudinal axis and the transversal extent is measured in a direction orthogonal to the longitudinal axis without loss of generality.

[0060] The three example acoustic portions are distributed along the center axis of the grille, with lateral symmetry (including substantial lateral symmetry) about the center axis. Adjacent acoustic portions on the grille are separated by a solid portion of the main body which is a non-acoustic portion. The separation distance between adjacent acoustic portions, or more exactly, adjacent driver apertures, are determined by the separation of the speaker drivers plus a diffusion span determined by a diffusion factor.

[0061 ] In the example speakers, it is desirable that a substantial or maximal portion of the grille is an acoustic region which is designed to permit maximal sound transmission with minimal distortion and minimal sound obstruction. Therefore, it is highly desirable that a substantial area portion or a maximum area portion of the grille is occupied by driver apertures and not by non-acoustic regions which are sound blocking regions. In the example grille, the space or empty area of the driver aperture occupies about 60% of the total grille surface area.

[0062] A speaker grille which is detachably attachable to a speaker main unit would generally require a rigid support portion to support the acoustic region and to maintain the speaker in a predefined or predetermined shape. However, a high space to non-space ratio would mean a reduced strength of the rigid support portion so that the rigid support portion is more susceptible to twisted distortion, for example, when the speaker grille is twisted about a twisting axis such as a diagonal line on the grille.

[0063] In an example grille of the present disclosure, each of the driver aperture on the main body is a large aperture which occupies a substantial transversal portion of the lateral extent of the grille. An aperture is large herein if its diameter or maximum transversal extent is 60% or more of the total lateral extent of the grille. For example, the example grille has a maximum or total lateral extent of about 200mm while the driver aperture has a diameter of 175mm, so that the maximum transversal extent of the driver aperture makes up 87.5% of the lateral extent of the main body. As a result of the high space or aperture ratio due to the major driver aperture, the man body has a very thin or narrow lateral border at the location where the driver aperture has its maximum lateral extent. In this example, the grille has a thin border having a width of approximately 12.5mm. As a result of the high aperture or space ratio, the grille is susceptible to twist-induced or other deformation unless duly reinforced. For completeness, the example grille has a longitudinal extent v, a lateral extent u, a driver aperture diameter d, a separation distance s1 , s2 between centers of adjacent driver apertures, and a thickness t, as depicted in Table 1 and Figures 3A, 3A1 , 3A2 and 3B. The lowest driver aperture has its center at a vertical distance s3 above the bottom transversal edge of the grille so that the portion of the grille which is between the lowest driver aperture and the bottom transversal edge has a minimum width of (125.8-175/2) = 38.3mm.

[0064] Table 1

[0065] Referring to Figures 3C, 3D and 4A, the example main body of the example speaker grille comprises a composite plate group, or a plate group composite. The plate group composite comprises a first rigid board 120 and a second rigid board 130. Each of the first rigid board and a second rigid board is a thermoset plastic board which has a very high rigidity and a very hard surface. Acrylic and Bakelite are example thermoset plastic materials and has a hardness of over 90 in the Shore D scale.

[0066] The example first rigid board 120 is an 1 mm thick Bakelite board and the example second rigid board 130 is a 1 5mm thick Bakelite board. The first rigid board and the second rigid board are physically and permanently fastened together by hot melt bonding, for example, by application of a 0.08mm thick and 115 °C hot melt film 126. An example plurality of three large apertures 123A, 123B and 123C is formed on each of the first rigid board and the second rigid board and the large apertures combined to form the driver apertures of the grille. The first large aperture 123A is an upper aperture corresponding to a top driver aperture which is closest to the upper transversal edge of the grille, the third large aperture 123C is a lower aperture corresponding to a bottom driver aperture which is closest to the lower transversal edge of the grille, and the second large aperture 123B is an intermediate aperture corresponding to an intermediate driver aperture located between the top and bottom driver apertures.

[0067] The first rigid board 120 has a first surface 122 which is an outward facing surface and a second surface which is a rearward-facing surface which is in abutment with the second rigid board. The second rigid board 130 has a first surface 132 which is an outward facing surface which in abutment with the first rigid board and a second surface which is an inward-facing surface opposite facing the speaker main unit. A plurality of through magnet holding bores is formed on the second rigid board and a corresponding plurality of magnet slabs is held inside the magnet holding bores. Each of the magnet slab is mounted inside a magnet holding bore with one of the magnetic surfaces exposed and facing rearwards towards the speaker main unit. Each of the magnet slab 124 has an associated ferromagnetic back plate to enhance magnetic field strength on the second surface of the second rigid board. The ferromagnetic back plate is in physical abutment with the magnetic surface of the magnet slab which is not exposed on the second surface of the second rigid board and is held intermediate the first and second rigid boards. The magnet slabs are distributed along the periphery or border of the second rigid board 130 and between the driver apertures and the edges to function as a distributed attachment means. The example magnet slab has a diameter or 15mm and a thickness of 1 mm and an example plurality of eight magnet slabs are mounted and distributed on the second rigid board, as depicted in Figure 4A.

[0068] A microfabric layer 110 is mounted on the plate group composite. The example microfabric layer has a thickness of 0.75mm and is physically and permanently bonded to the plate group composite by hot melt bonding, for example, by application of a 0.08mm thick and 115 °C hot melt film 112. The microfabric layer is perforated at the acoustic regions and an example perforation region is depicted in Figure 3E. The microfabric layer is not perforated outside the acoustic regions to conceal the plate group composite so that appearance of the plate group composite is hidden or not exposed. Referring to Figure 3E, the perforation pattern comprises a plurality of holes of uniform size and the holes are distributed at regular spatial distances along concentric rows R2 - R25. The example rows are distributed at an example radial separation distance of 7mm and each of the example hole has a diameter of 2.4 mm. The example perforation pattern comprises 1801 holes for each driver position. The example perforations are formed by laser but can be formed by stamping or other formation means without loss of generality.

[0069] The microfabric layer is held under tension to stay taut while being bonded to the plate group composite. The holding tension is radial to provide radial tension around the periphery of the driver aperture to provide additional strength across the driver aperture and additional resistance to twisting deformation.

[0070] To optionally provide reinforcement, a 0.2mm polycarbonate sheet 114 is bonded to the plate group composite and intermediate the plate group composite and the microfabric layer. Likewise, the optional polycarbonate sheet and the plate group composite may be bonded by using a hot-melt film 112A.

[0071 ] Optionally, a 0.6mm lining layer 116 is bonded between the plate group composite and the microfabric layer or between the optional polycarbonate sheet and the plate group composite. The lining layer may be a polyurethane layer and the polyurethane lining layer may be bonded to the polycarbonate sheet and plate group composite using similar hot-melt films 112B.

[0072] The inward-facing surface of the grille is a rearward-facing surface which is in abutment with the speaker main unit when the grille is attached to the speaker main unit. The rearward facing surface is optionally covered by an inner lining layer 160 so that the rearward -facing surface has a look and feel similar to the microfabric cover layer on the outward-facing surface of the grille. The optional inner lining layer also helps to hide or conceal the texture or appearance of the plate group composite when the grille is detached from the speaker main unit. The inner lining layer may be a polyurethane layer and the polyurethane lining layer may be bonded to the plate group composite using similar hot-melt films 162. Alternatively, an inner lining layer 160 may be a microfabric layer without loss of generality.

[0073] In some embodiments, an intermediate backing layer 164 is bonded intermediate the plate group composite and the inner lining layer. The intermediate backing layer 164 may be a 0.2mm FR4 or polycarbonate sheet. Likewise, intermediate backing layer 164 may be bonded using similar hot-melt films 162A.

[0074] Only a single large aperture has been shown on the first five layers of the grille of Figure 4A for simplicity. It should be appreciated that there are three larger apertures in an actual product to correspond to the three driver apertures without loss of generality. [0075] After the formation of the plate group composite (including the optional layers where appropriate) a layer of resin is applied along the outer periphery of the grille and the inner peripheries of the driver apertures to form a smooth edge and to provide an integral appearance.

[0076] Referring to Figures 3G and 3F, the taut microfabric layer defines the outermost layer and the outward-facing surface 102 of the composite grille 100. The taut and perforated microfabric layer which forms an acoustic portion is at an axial distance away from the back surface of the composite grille which is the rearward-facing surface of the grille. The axial separation distance in this example is measured along the driver axis and is approximately equal to the thickness of the plate group composite (including the optional layers where appropriate). Since the plate group composite has a small thickness, the grille also has a very small thickness, for example, less than 8mm, making a sleek design with a reasonable twisting resistance possible. Optionally, outside walls 106 of the composite grille 100 are painted by color resin with color close to the microfabric layer 110. Inside walls 108 surrounding driver apertures are painted by color resin with color close to the 5th layer lining.

[0077] Referring to Figures 3C and 3D, the composite grille 100 comprises a composite plate group which is enclosed within an inner lining layer and an outer lining layer. The example outer lining is a taut microfabric layer having a forward-facing outer surface 102 and the example inner lining layer is a taut polyurethane layer having a rearward-facing inner surface 104. In some embodiments, the inner lining layer may be a taut microfabric layer. In some embodiments, the outer lining layer may be a taut polyurethane layer. A plurality of magnet slabs is embedded in the composite plate group to define a distributed attachment means and a distributed self-attachment surface which is concealed underneath the inner lining layer.

[0078] For completeness, example dimensions and materials of the example grille are as depicted in Table 2 below and the symbol N in Figure 3C denotes north magnetic field:

[0079] Since the acoustic region is formed on a driver aperture on the composite plate group, the acoustic portion which is defined by the perforated region of the outer lining layer is at a small axial separation distance from the rearward -facing surface of the grille. As the thickness of the grille is substantially smaller than an MDF grille, the maximum dimensions of the driver aperture are smaller on the present grille due to a smaller forward diffusion distance away from the speaker driver surface.

[0080] The microfabric layer in the acoustic region is not bonded to the plate group composite in the axial direction. It imposes little or no physical or audio resistance on the speaker driver and is free to absorb incoming vibration and move synchronously with the sound waves. Since it is capable of absorbing this vibration, the grille is less prone to rattling except at extremely high sound pressure levels. On the other hand, the portion of the microfabric layer which is physically and directly bonded on the plate group composite in the non-acoustic region is not free to move in response to sound propagated from a corresponding driver. As a result, the acoustic portion of the microfabric layer forward of each speaker driver in the acoustic region is independently movable. In addition, the microfabric layer would move only in response to the sound waves produced by the corresponding speaker driver which is directly behind it, and not move by sound waves produced by other, non-corresponding speaker drivers.

[0081 ] In some embodiments, the plate group composite may be integrally formed as a single thermoset plastic rigid board 180, as depicted in the example of Figure 5. Magnet slabs are held in magnet bores integrally formed on the single board. 180 The example rigid board 180 is a 2.5mm thick Bakelite board, which is the combined thickness of the first rigid board 120 and the second rigid board 130. Therefore, the right board 180 can provide the same mechanical strength as the example plate group composite comprising the first rigid board 120 and the second rigid board 130. However, since there is no hot melt glue film therebetween, the thickness of the grille can be further reduced, as depicted in Figure 5A. [0082] For completeness, example dimensions and materials of the example grille are as depicted in Table 3 below and the symbol N in Figure 5 denotes north magnetic field:

[0083] Microfiber (or microfibre) is fabric material comprising synthetic fibers finer than one denier or having a diameter of less than ten micrometers. The most common types of microfibers are made from polyesters, polyamides (e.g., nylon, Kevlar, Nomex, trogamide), or a conjugation of polyester, polyamide, and polypropylene. Microfibers suitable for industrial usage are credited to Dr Miyoshi Okamoto and Dr Toyohiko Hikota. While microfabric materials are used as example herein, microfabric materials herein include synthetic materials having properties similar to microfibers and can be used for the present applications.

[0084] While the outermost layer of example grilles is a microfabric layer, it will be appreciated that the acoustic regions may be formed of other acoustic fabrics, including woven and non-woven fabrics, including synthetic and non-synthetic fabrics, and especially synthetic fabrics having a high-tensile strength. Where the exterior layer of the grille is a non-microfabric layer, the descriptions herein are to be applied mutatis mutandis, for example, exchanging the terms microfiber with woven-fiber and microfabric with woven-fabric without loss of generality. Since an acoustic portion is critical to or determinative of the sound performance of a speaker grille, the acoustic portion should be as thin as possible to provide good audio performance (or to mitigate sound degradation) while providing a strong enough physical shielding to provide a good degree of protection against inadvertent physical touch of a speaker driver. In some embodiments, the acoustic regions may be formed of polyurethane, for example, textured polyurethane to give a leather look and feel.

[0085] In general, speaker drivers include a diaphragm that moves back and forth to create pressure waves in the air column in front, and depending on the application, at some angle to the sides. A speaker driver here (“driver” in short) is an individual loudspeaker transducer that converts an electrical audio signal to sound waves. A speaker driver has a driver axis which in the example is at the center of the driver and extends orthogonally away from the front surface of the front panel. Each speaker has an acoustic surface which is to deliver sound outwardly and away from the speaker.

[0086] While examples and embodiments have been described herein, persons skilled in the art would understand and appreciate that the examples and embodiments are to assist understanding and are not intended to be limiting or restrictive. For example, while the example acoustic portions are formed by perforations of selected areas on a microfabric surface layer, a woven fabric having an inherent high-fidelity sound permeability may be used to form the acoustic region. In example embodiments, woven materials having a space ratio of 55% or more are used to form the acoustic regions. The woven material may be a woven fabric, and the woven fabric may be mounted on a plate group composite which forms a rigid supporting skeleton to form a firm grille having a high twist resistance. In some embodiments, the woven fabric may extend across the entire outer surface of the grille. In some embodiments, the woven fabric has a higher or very high weaving density (and a low space ratio of below 10%) outside the acoustic regions and a lower or a very low weaving density (and a high space ratio of above 55%).

[0087] Table of numerals

Claims

1 . A composite speaker grille comprising a substrate member and a taut microfabric layer extending over a front surface of the substrate member to form an outward-facing surface of the grille, wherein the substrate member is formed of a molded synthetic material of high rigidity and comprises an acoustic region and a non-acoustic region, wherein one driver aperture or a plurality of driver apertures is formed on the substrate member to form the acoustic region; and wherein the microfabric layer includes an acoustic portion which is perforated and covers the acoustic region of the substrate member and a non-acoustic portion which is surface-mounted on the substrate member to cover the non-acoustics region of the substrate member.

2. The speaker grille according to Claim 1 , wherein the substrate member has a longitudinal axis which extends to define a longitudinal direction and a transversal axis which extends to define a transversal direction orthogonal to the longitudinal direction, and wherein the microfabric layer extends taut along the longitudinal direction and along the acoustic region and/or extends taut along the transversal direction and along the acoustic region.

3. The speaker grille according to Claims 1 or 2, wherein the substrate member has a maximum space ratio of 70% or higher in the longitudinal direction and/or in the transversal direction, including 75% or higher, 80% or higher, 85% or higher, and a range or ranges defined by any of the aforesaid values.

4. The speaker grille according to any preceding Claim, wherein the acoustic portion has a space ratio of 60% or higher, including 61 % or higher, 62% or higher, 63% or higher, 64% or higher, 65% or higher, 66% or higher, 67% or higher, 68% or higher, 69% or higher, or 70% or higher.

5. The speaker grille according to any preceding Claim, wherein the driver aperture is defined to center about a driver axis, wherein the driver axis is orthogonal or at an angle to the outward facing surface of the grille, and the acoustic portion is taut in radial directions with respect to the driver axis.

6. The speaker grille according to any preceding Claim, wherein the grille has a pair of lateral edges defined by a pair of longitudinal sides, wherein the grille at a longitudinal location has a width which is defined by separation distance between the lateral edges in a transversal direction orthogonal to the longitudinal sides, wherein the backplate has a minimum width portion at a longitudinal location where the driver aperture has a maximum lateral extent; and wherein the minimum width is 20% or less of the width of the grille, including 19% or less, 18% or less, 17% or less, 16% or less, 15% or more, or a range or ranges having limits set by any of the aforesaid values.

7. The speaker grille according to any preceding Claim, wherein the substrate member has a minimum width at a longitudinal location and where the driver aperture has a maximum lateral extent; wherein the substrate member has a minimum edge to driver aperture separation distance at the longitudinal location; and wherein minimum edge to driver aperture separation distance is 10% or less of the width of the substrate member, including 9% or less, 8% or less, 7.5% or less, 7% or less, 6.5% or less, 6% or more, or between 1 cm and 1 .5cm, or a range or ranges having limits set by any of the aforesaid values.

8. The speaker grille according to any preceding Claim, wherein a plurality of driver apertures is formed on the substrate member and the substrate member has a minimum inter-driver aperture separation; and wherein the minimum inter-driver aperture separation is 10% or less of the width of the substrate member, including 9% or less, 8% or less, 7.5% or less, 7% or less, 6.5% or less, 6% or less, 5.5% or less, 5% or more, or between 0.8cm and 1 .5cm, or a range or ranges having limits set by any of the aforesaid values.

9. The speaker grille according to any preceding Claim, wherein the grille has an inward-facing surface which is a back surface that is opposite facing to the outward facing surface, wherein the perforated microfabric acoustic portion of the microfabric layer is at a forward separation distance from the back surface; and wherein forward separation distance is comparable to the thickness of the substrate member or is at 8.5mm or less, including 8mm or less, 7mm or less, 6mm or less, 5mm or more, or a range or ranges having limits set by any of the aforesaid values.

10. The speaker grille according to any preceding Claim, wherein the substrate member has a substantially uniform thickness and the thickness of the microfabric layer is substantially smaller than the thickness of the substrate member; and wherein the substrate member has a thickness of 4mm or less, including 3.5mm or less, 3mm or less, 2.5mm or less, 2mm or more, or a range or ranges having limits set by any of the aforesaid values.

1 1 . The speaker grille according to any preceding Claim, wherein the substrate member comprises a thermoset hard plastic plate, such as a Bakelite plate; and/or wherein the substrate member is a composite plate member comprising a plurality of thermoset hard plastic plates physically joined together.

12. The speaker grille according to any preceding Claim, wherein the substrate member comprises a first plate member which is a forward-facing plate having a forward facing surface and a second plate member which is a rearward -facing plate having a rearward facing surface, wherein each one of the forward-facing plate and the rearward-facing plate a thermoset hard plastic plate such as a Bakelite plate; and wherein the forward-facing plate and the rearward-facing plate are physically joined by hot melt.

13. The speaker grille according to Claim 12, wherein a plurality of magnet slabs each having a pair of opposite facing magnetic surfaces of opposite magnetic properties is embedded inside the second plate member, wherein the magnet slabs are distributed along lateral sides of the grille, and wherein the magnet slabs are disposed such that that magnetic surfaces are exposed on the a rearward-facing surface of the second plate member.

14. The speaker grille according to any preceding Claim, wherein the substrate member has a rearward-facing surface which is to face a speaker main body when attached to a speaker; wherein the grille comprises an attachment means having an attachment surface for self attachment to the speaker main body; and wherein the attachment surface is flush or almost flush with the inward facing surface.

15. The speaker grille according to any preceding Claim, wherein the grille has an inward-facing surface which is to oppositely face and in abutment with a speaker main body when attached to a speaker; wherein the grille comprises an attachment means having an attachment surface for self-attachment to the speaker main body; and wherein the attachment means is distributed on the inward-facing surface and is flush therewith.

16. The speaker grille according to any preceding Claim, wherein the substrate member has a hard surface and the substrate member is twist-deformable about a diagonal line of the substrate member and wherein the taut microfabric layer increase twist-deformation resistance of the substrate member by at least 20%.

17. The speaker grille according to any preceding Claim, wherein the microfabric layer has a thickness of a thickness of 1 2mm or less, including 1 .1 mm or less, 1 .0mm or less, 0.9mm or less, 0.8mm or less, 0.7mm or less, 0.6mm or more, or a range or ranges having limits set by any of the aforesaid values.

18. The speaker grille according to any preceding Claim, wherein the perforated microfabric acoustic portion of the microfabric layer is a taut planar layer.

19. The speaker grille according to any preceding Claim, wherein the speaker grill comprises a plurality of sound transmission portions and each sound transmission portion corresponds to an acoustic portion of the microfabric layer; and wherein adjacent acoustic portions are separated by a non-acoustic portion.

20. The speaker grille according to any preceding Claim, wherein the microfabric layer is held taut on the substrate member by a hot-melt glue film.

21 . The speaker grille according to any preceding Claim, wherein the microfabric layer has a suede feel and texture.

22. A method of forming a speaker grille, wherein the method comprises:

Forming a composite substrate member, the composite substrate member comprising one driver aperture of a plurality of driver apertures; and

Mounting a microfabric layer on the composite substrate member, the microfabric layer comprising acoustic regions which are perforated for sound transmission; wherein the acoustic regions are mounted taut and extend across the driver aperture or driver apertures.

23. The method according to Claim 22, wherein the acoustic regions of the microfabric layer is perforated and having a space ratio of 55% or more, including 60% or more, 65% or more.

24. The method according to Claims 23 or 24, further comprising forming self-attachment means on an inward facing surface of the speaker grille, the inward facing surface being in abutment with a speaker main body during use when the grille is attached to the speaker main body.

25. The method according to any preceding Claim, wherein the method comprises forming perforations on the acoustic regions by laser.

26. The method according to any preceding Claim, wherein the method comprises forming perforations of uniform size and separation.

27. The method according to any preceding Claim, wherein the method comprises forming a PU layer on an or the inward facing surface of the speaker grille.

28. A speaker comprising a grille according to any preceding Claim or a grille made according to any of the preceding method.