Front mounted flat panel loudspeaker assembly

Abstract

A flat panel loudspeaker includes a planar resonant panel insertable into an opening in the mounting surface and including a front surface and a rear surface. The front surface faces outward in the mounting surface. The loudspeaker also includes an exciter coupled to the rear surface of the planar resonant panel and a support frame for mounting in the mounting surface. The rear surface of the planar resonant panel is fixed thereto around substantially the whole of the outer boundary of the planar resonant panel. The outer boundary of the planar resonant panel is fixed relative to the mounting surface. The loudspeaker further includes at least one tab configured to extend away from the support frame and be substantially flush with the front surface of the planar resonant panel, which is substantially flush with the mounting surface when the tab is against the mounting surface.

Claims

1. A flat panel loudspeaker configured for mounting in an opening in a mounting surface, the flat panel loudspeaker comprising: a planar resonant panel insertable into an opening in the mounting surface and comprising a front surface, wherein the front surface faces outward in the mounting surface when the flat panel loudspeaker is mounted in the mounting surface, and the planar resonant panel further comprises a rear surface opposite the front surface; an exciter coupled to the rear surface of the planar resonant panel to cause the planar resonant panel to vibrate and generate sound in response to operation of the exciter; a support frame for mounting in the mounting surface and having the rear surface of the planar resonant panel fixed thereto around substantially the whole of the outer boundary of the planar resonant panel, such that when mounted in the mounting surface and when the planar resonant panel is caused by the exciter to vibrate in response to operation of the exciter, the outer boundary of the planar resonant panel is fixed relative to the mounting surface; and at least one tab, configured to extend away from the support frame in a tab direction parallel to the mounting surface and substantially flush with the front surface of the planar resonant panel when the flat panel loudspeaker is mounted in the mounting surface, wherein the front surface of the planar resonant panel is substantially flush with the mounting surface when the tab is against the mounting surface.

2. The flat panel loudspeaker of claim 1 wherein the at least one tab comprises a plurality of tabs, and wherein one or more of the plurality of tabs are provided substantially at a corner of the front surface of the planar resonant panel.

3. The flat panel loudspeaker of claim 2 wherein each of the one or more of the plurality of tabs are spaced no more than 30 millimeters from the corner at which the respective tab is substantially provided.

4. The flat panel loudspeaker of claim 3 wherein an outer edge of each of the one or more of the plurality of tabs is spaced at least 10 millimeters from the corner at which the respective tab is substantially provided.

5. The flat panel loudspeaker of claim 1 wherein the front surface of the planar resonant panel is substantially rectangular, having two short sides and two long sides, and wherein the at least one tab extends in the tab direction beyond one of the short sides.

6. The flat panel loudspeaker of claim 5 wherein the at least one tab extends in the tab direction beyond the short side by a first extension amount greater than any second extension amount beyond the long side.

7. The flat panel loudspeaker of claim 6 wherein the at least one tab extends substantially from the short side.

8. The flat panel loudspeaker of claim 7 wherein the at least one tab extends only beyond the short side.

9. The flat panel loudspeaker of claim 1 wherein the at least one tab has a thickness of less than 1 mm.

10. The flat panel loudspeaker of claim 1 wherein the at least one tab has defined therein a through-recess having at least a partially concave boundary engageable by a headed fastener for securing the at least one tab to the mounting surface during mounting.

11. The flat panel loudspeaker of claim 10 wherein the through-recess is an open recess.

12. The flat panel loudspeaker of claim 10 wherein the through-recess is countersunk.

13. The flat panel loudspeaker of claim 12 wherein the through-recess defines a first recess portion disposed at a front surface of the tab and a second recess portion extending to a rear surface of the tab, wherein the second recess portion tapers more acutely than the first recess portion relative to an axis of the through-recess from the front surface of the tab to the rear surface of the tab.

14. The flat panel loudspeaker of claim 1 further comprising a mounting unit for mounting in the mounting surface and having the planar resonant panel and exciter provided therein.

15. The flat panel loudspeaker of claim 14 wherein the at least one tab extends from the mounting unit.

16. The flat panel loudspeaker of claim 14 wherein a surface of the mounting unit has defined therein at least one hole arranged to facilitate sound to pass from within the mounting unit out of the flat panel loudspeaker to a mounting cavity defined rearward of the mounting surface.

17. The flat panel loudspeaker of claim 1 wherein the at least one tab is frangibly connected to at least one of the support frame or the planar resonant panel.

18. A method for mounting the flat panel loudspeaker of claim 1 in a mounting surface facing outward, the method comprising: inserting the flat panel loudspeaker into an opening defined in the mounting surface and sized to fit the planar resonant panel of the flat panel loudspeaker therein until the at least one tab is against the mounting surface, wherein the front surface of the planar resonant panel substantially flush with the mounting surface; and securing the flat panel loudspeaker in the mounting surface.

19. The method of claim 18 wherein the at least one tab has defined therein a through-recess having at least a partially concave boundary engageable by a headed fastener for securing the at least one tab to the mounting surface during mounting, the method further comprising forming the through-recess by: performing a first punching operation using a first punch tool defining a first punch head; and performing a second punching operation using a second punch tool defining a second punch head, wherein the second punching operation is performed subsequent to the first punching operation.

20. The method of claim 19 wherein the first punch head is smaller than at least a portion of the second punch head.

21. The method of claim 19 wherein the first punch head tapers more acutely to a first punch tip than the second punch head tapers to a second punch tip.

22. The flat panel loudspeaker of claim 1 wherein the at least one tab extends in the tab direction beyond a side of the planar resonant panel.

23. The flat panel loudspeaker of claim 1 wherein the tab includes a proximal portion and a tapered distal portion, the tapered distal portion including a through recess.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the invention are further described hereinafter with reference to the accompanying drawings, in which:

(2) FIGS. 1A, 1B and 1C are illustrations of an embodiment of a flat panel loudspeaker as disclosed herein;

(3) FIG. 2 is an illustration of a tab as disclosed herein;

(4) FIGS. 3A and 3B are illustrations of another embodiment of a flat panel loudspeaker as disclosed herein;

(5) FIG. 4 is an illustration of an alternative embodiment of a flat panel loudspeaker as disclosed herein having different tabs;

(6) FIGS. 5A, 5B and 5C are illustrations of a tab of the embodiment of FIG. 4; and

(7) FIGS. 6A to 6F are schematic illustrations of steps in a manufacturing method for forming the tabs for the flat panel loudspeaker.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIGS. 1A, 1B and 1C illustrate different views of an embodiment of a flat panel loudspeaker 100 for mounting in an opening in a mounting surface. The mounting surface (not shown) is an exposed surface of a structural component of a building, such as a wall, a ceiling, an air conditioning unit, or the like. In examples, the opening in the mounting surface is defined by a series of cuts in the mounting surface, resulting in a substantially rectangular opening in the mounting surface which is sufficiently deep to contain the flat panel loudspeaker. Alternatively, the opening can be provided by means of the construction of the mounting surface. In other words, the mounting surface can be formed to have the opening defined therein.

(9) FIG. 1A provides a view of the loudspeaker 100, showing outwardly facing features of the flat panel loudspeaker 100. The loudspeaker 100 comprises a planar resonant panel 110. The resonant panel 110 extends across substantially the whole of a front surface of the flat panel loudspeaker 100. The resonant panel 110 is formed, in the embodiment of FIG. 1A, to have a four-sided front surface, in the form of a rectangular front surface. Suitable materials and methods of construction for manufacturing the resonant panel 110 for use to generate sound in a flat panel loudspeaker will be known to the skilled person. The rectangular front surface is defined by two short sides spaced apart and connected by two long sides, also spaced apart. As will be apparent, the short sides are shorter than the long sides and are the sides of the front surface perpendicular to the long sides. In other words, the front surface of the resonant panel 110 is rectangular. It will be understood that the present disclosure is not limited to a resonant panel having a front surface of a rectangular shape, and other shapes are also possible, for example circular.

(10) The loudspeaker 100 further comprises at least one tab 120a, 120b, 120c, 120d, in the form of four tabs 120a, 120b, 120c, 120d. The tabs 120a, 120b, 120c, 120d extend away from the resonant panel 110 in a tab direction, as will be described further with reference to FIG. 1C hereinafter. In this embodiment, the four tabs 120a, 120b, 120c, 120d are provided substantially at, for example at, the corners of the front surface of the resonant panel 110. It will be understood that the present disclosure is not limited to having four tabs, and other numbers are also possible, for example two tabs. Each of the tabs 120a, 120b, 120c, 120d, in this embodiment, extends away from the short side of the front surface of the resonant panel 110. Each of the tabs 120a, 120b, 120c, 120d, in this embodiment, extends, of the short sides and the long sides of the front surface of the resonant panel 110, only beyond the short side of the front surface of the resonant panel 110. The skilled person would understand that in other examples, the at least one tab 120a, 120b, 120c, 120d can extend substantially away from, for example away from, a long side of the resonant panel. The at least one tab 120a, 120b, 120c, 120d can extend beyond the short side of the front surface of the resonant panel by a first extension amount greater than any second extension amount beyond the long side of the front surface of the resonant panel 110.

(11) The loudspeaker further comprises connectors 130 for connecting cables to one or more internal electrical components of the loudspeaker 100.

(12) The loudspeaker also comprises an exciter (not shown). The exciter is coupled to the rear surface of the resonant panel 110 and, when in operation, causes the resonant panel 110 to vibrate and generate sound. The exciter is typically operated by one or more electrical signals received via the connectors 130. The exciter is connected to the rear surface of the resonant panel via a ‘foot’ (not shown), for example a cylindrical foot. The exciter can be driven by the one or more electrical signal received at terminals thereof from, for example, an audio amplifier unit (not shown), via conductive cables attached to the connectors 130. When caused to vibrate by the exciter, the resonant panel 110 acts to amplify these vibrations in a similar manner to a soundboard of a violin or piano such that the flat panel loudspeaker 100 produces sound from the electrical signal. The above description of the operation of the exciter and the resonant panel 110 is provided merely for the convenience of the reader. The skilled person will understand how flat panel loudspeakers typically operate.

(13) FIG. 1B provides a further view of loudspeaker 100, showing an inwardly facing aspect of the loudspeaker. The at least one tab 120a, 120b, 120c, 120d and the connectors 130 are again shown in FIG. 1B, but from a rear side.

(14) The loudspeaker 100 also comprises a support frame 140. The rear surface of the resonant panel 110 is fixed to the support frame 140 around the whole of, or substantially the whole of, the outer boundary of the resonant panel 110. This ensures that when the resonant panel is mounted in the mounting surface, and when an operation of an exciter is causing the resonant panel to vibrate, the outer boundary of the resonant panel is fixed relative to the mounting surface. This helps to prevent any plaster layers covering the mounted loudspeaker from cracking or distorting. In this way, the loudspeaker 100 can remain invisible in the mounting surface.

(15) The loudspeaker 100 in this example also comprises a mounting unit 150. The mounting unit 150 is mounted to the support frame 140 and is for receiving therein the exciter, the resonant panel 110, and other components of the loudspeaker 100. In particular, the mounting unit 150 can protect a rear portion of the resonant panel 110 and the exciter during installation of the flat panel loudspeaker 100 in the mounting surface. Furthermore, the mounting unit 150 can define a cavity rearward of the resonant panel 110. When the resonant panel 110 is actuated by operation of the exciter, sound generated rearwardly from the resonant panel 110 can resonate within the cavity defined by the mounting unit 150, enhancing the audio performance of the flat panel loudspeaker 100. When the loudspeaker 100 includes a mounting unit 150, the at least one tab 120a, 120b, 120c, 120d can extend directly from the mounting unit 150. In other words, the at least one tab 120a, 120b, 120c, 120d can be connected to the rest of the flat panel loudspeaker 100 via the mounting unit 150. In an alternative example, the at least one tab 120a, 120b, 120c, 120d can be connected to the rest of the flat panel loudspeaker 100 via the support frame 140.

(16) FIG. 1C provides a side view of the loudspeaker 100. The resonant panel 110 is shown affixed to the support frame 140. The mounting unit 150 is affixed to the support frame 140 and supports the connectors 130. As best seen in FIG. 1C, the at least one tab 120a, 120b, 120c, 120d extends away from the support frame 140 in a tab direction. The tab direction is parallel to the mounting surface when the flat panel loudspeaker 100 is to be mounted in the mounting surface. In other words, the tab direction is parallel to the front surface of the resonant panel 110. The tab direction is also substantially flush with the front surface of the resonant panel 110 when the flat panel loudspeaker 100 is to be mounted in the mounting surface. In this example, a rear surface of the tab 120a, 120b, 120c, 120d, that is, the surface that engages with the mounting surface is arranged to be flush with the front surface of the resonant panel 110. In another example, a front surface of the tab 120a, 120b, 120c, 120d, that is the surface which faces away from the mounting surface, can be flush with the front surface of the resonant panel. The alternative approach is suitable where the tab 120a, 120b, 120c, 120d is to be indented into the mounting surface.

(17) The opening in the mounting surface is sized to be larger than the resonant panel 110 and support frame 140, but small enough that when mounting the loudspeaker 100, the at least one tab 120a, 120b, 120c, 120d does not pass within the opening, and instead engages flush with the mounting surface to prevent the front surface of the resonant panel 110 from passing into the opening of the mounting surface. In other words, a size of the resonant panel 110 in combination with the at least one tab 120a, 120b, 120c, 120d is greater than the extent of the opening in the mounting surface.

(18) Once the at least one tab is flush with the mounting surface and the loudspeaker 100 is within the opening of the mounting surface, the loudspeaker 100 can be fixed in place by means of a fastener engageable with the at least one tab, as described further with reference to FIG. 2 hereinafter. It will be understood that the loudspeaker 100 can be secured in the mounting surface by another means, for example gluing the loudspeaker 100 or a component thereof to the mounting surface.

(19) The mounting unit 150 may be formed from metal, for example steel, or from another material, such as carbon fiber.

(20) FIG. 2 is an illustration of the tab 120a, shown in isolation. Each of the other tabs 120b, 120c, 120d of the flat panel loudspeaker described with reference to FIGS. 1A to 1C are substantially similar. The tab 120a has defined therein a through-recess 210. The through-recess 210 is provided in a distal portion 215 of the tab 120a. The through-recess 210 has a boundary which is at least partly concave. The boundary is to engage with a headed fastener, such as a screw or a nail, to secure the tab 120a to the mounting surface during mounting. The tab 120a is connected to the support frame 140 at a proximal portion 216 of the tab 120a, in particular at an inner edge 220 of the tab. The inner edge 220 is provided at an opposite end of the tab 120a to the through-recess 210.

(21) When securing the loudspeaker to the mounting surface using a headed fastener, the shaft of the headed fastener can pass beyond the mounting surface and into a layer of a second material behind the material of the mounting surface. The second material is typically a stronger material than the material of the mounting surface, to provide a structural piece for the headed fastener to fix into, and to clamp the mounting surface between the tab and the second material. The second material could be a strip of wood, a wooden noggin, a ply layer, a plastic strip or a metal frame, although the second material is not limited thereto. The second material could already be present behind the mounting surface at the start of the installation, or could be fitted behind the mounting surface as part of the installation process.

(22) In the example of FIG. 2, the through-recess 210 is an open recess 210 open at an outer edge 221 of the tab, such that the boundary of the recess 210 does not form a complete loop. The outer edge 221 is separate from the inner edge 220. The open recess can sometimes be referred to as a notch.

(23) The through-recess 210 is narrower at an opening of the through-recess 210. The distance D1 at the opening of the through-recess is less than the distance D2 at the widest point of the through-recess. In this way, a headed fastener having a tapered head can be substantially centered in the through-recess 210. The boundary of the through-recess 210 can define an arc of a circle.

(24) The through-recess 210 can be tapered in a through-direction of the tab 120a. In other words, the through-recess 210 may be countersunk, such that the diameter of the recess 210 at a front surface of the tab 120a is larger than the diameter of the recess 210 at the rear surface of the tab 120a. The rear surface is the surface that is engageable with the mounting surface during mounting of the flat panel loudspeaker 100. This allows the head of the headed fastener inserted into the recess to sit flush with the tab. For the avoidance of doubt, FIG. 2 is merely a diagrammatic representation of the tab 120a, and does not show the countersunk feature of the through-recess 210. An example of a countersunk through-recess is illustrated by reference to FIGS. 5A to 5C.

(25) The tab 120a in this embodiment is formed from sheet metal, for example steel, which may be stainless steel, and is thin to minimize the number of layers of plaster that are required to cover the tab 120a to make the tab 120a appear invisible in the mounting surface once the loudspeaker 100 is mounted. It will be understood that the tab 120a could be formed from other materials, such as carbon fiber. The tab 120a could be made in one piece integrally formed with the resonant panel and/or the support frame.

(26) The tab 120a has a thickness of less than 5 mm, for example less than 3 mm, for example less than 2 mm, for example less than 1 mm, for example, approximately 0.8 mm. The tab 120a has a thickness of at least 0.2 mm so that the tab 120a is sufficiently sturdy to remain attached to the rest of the flat panel loudspeaker 100 during mounting, and to engage with the mounting surface without being substantially deformed.

(27) FIGS. 3A and 3B illustrate different views of another embodiment of a flat panel loudspeaker 300 for mounting in an opening in a mounting surface.

(28) FIG. 3A provides a view of loudspeaker 300 from the rear of the device, and FIG. 3B provides a view of the loudspeaker 300 from the side. The flat panel loudspeaker 300 is substantially similar to the flat panel loudspeaker 100 described with reference to FIGS. 1A to 1C, including the tab 120a described with reference to FIG. 2, unless otherwise described hereinafter. As previously, the loudspeaker 300 comprises at least one tab 320a, 320b, 320c, 320d located substantially at a corner of a resonant panel 310. The rear surface of the resonant panel 310 is attached to a support frame 340 around substantially the whole of the outer boundary of the resonant panel 310.

(29) The loudspeaker 300 also comprises an exciter (not shown), which is coupled to the rear surface of the resonant panel 310 and, when in operation, causes the resonant panel 310 to vibrate and generate sound. The support frame 340 supports the resonant panel 310, such that when the exciter is in use and causing the resonant panel to vibrate, the outer boundary of the resonant panel 310 is fixed relative to the mounting surface.

(30) The loudspeaker 300 further comprises connectors 330, attached in this embodiment to the support frame 340. The connectors are used to connect external cables to one or more internal components of the loudspeaker 300.

(31) The loudspeaker 300 further comprises a mounting unit 350. The rear surface of the mounting unit comprises a plurality of panels 352a, 352b, 352c, 352d, 352e, 352f, 352g, 352h, 352i, 352j, 352k, 352l, 352m. Panel 352a is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352b, and one edge adjoining panel 352c. Panel 352b is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352a, and one edge adjoining panel 352e. Panel 352c is a quadrilateral panel in the form of a trapezoidal panel with a first edge provided at the support frame 340, a second edge, parallel to the first edge, adjoining panel 352d, a third edge, connecting the first edge and the second edge and adjoining panel 352a and a fourth edge, also connecting the first edge and the second edge and adjoining panel 352f. Panel 352d is a triangular panel with one edge adjoining panel 352c, one edge adjoining panel 352e, and one edge adjoining panel 352h. Panel 352e is a triangular panel with one edge adjoining panel 352b, one edge adjoining panel 352d, and one edge adjoining panel 352i. Panel 352f is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352c, and one edge adjoining panel 352g. Panel 352g is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352f, and one edge adjoining panel 352h. Panel 352h is a triangular panel with one edge adjoining panel 352d, one edge adjoining panel 352g, and one edge adjoining panel 352l. Panel 352i is a triangular panel with one edge adjoining panel 352e, one edge adjoining panel 352j, and one edge adjoining panel 352l. Panel 352j is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352i, and one edge adjoining panel 352k. Panel 352k is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352j, and one edge adjoining panel 352m. Panel 352l is a triangular panel with one edge adjoining panel 352h, one edge adjoining panel 352i, and one edge adjoining panel 352m. Panel 352m is a triangular panel with one edge adjoining the support frame 340, one edge adjoining panel 352l, and one edge adjoining panel 352k.

(32) The panels 352a-m are planar and are arranged in a plurality of different directions. In this way, sound interference can be reduced within the mounting unit 350, thereby improving the sound quality of the loudspeaker 300. In this particular example, the panels 352a-m each face in a different direction.

(33) The mounting unit 350 can have defined therein at least one opening 360a, 360b in at least one of the panels 352a-m. In this embodiment, there are two openings 360a in panel 352i and two openings 360b in panel 352l, although this is just an example and the numbers and locations of the at least one opening 360a, 360b is not limited to these numbers or panels. The at least one opening 360a, 360b allows the sound produced by the exciter in combination with the resonant panel 310 to pass into a larger cavity provided within the mounting surface to resonate therein. This improves the acoustic performance of the loudspeaker 300, particularly for low frequency sounds, since low frequency sounds require larger spaces to fully resonate.

(34) FIGS. 4 and 5A to 5C illustrate different views of another embodiment of a flat panel loudspeaker 400 for mounting in an opening in a mounting surface.

(35) FIG. 4 provides a top perspective view of loudspeaker 400. The flat panel loudspeaker 400 is substantially similar to the flat panel loudspeaker 100 described with reference to FIGS. 1A to 1C and the flat panel loudspeaker 300 of FIGS. 3A and 3B unless otherwise described hereinafter. As previously, the loudspeaker 400 comprises at least one tab 420a, 420b, 420c, 420d located substantially at a corner of a resonant panel 410. The rear surface of the resonant panel 410 is attached to a support frame 440 around substantially the whole of the outer boundary of the resonant panel 410. The loudspeaker 400 may comprise a mounting unit (not shown) such as the mounting units 150, 350 described previously. In this embodiment, each tab 420 has a through recess 470 with a closed boundary forming a hole to receive a fastener therethrough. The through-recess 470 is countersunk.

(36) Although each of the tabs 420a, 420b, 420c, 420d in FIG. 4 have been shown located substantially at a corner of a resonant panel 410, another embodiment of the loudspeaker 400 is envisaged in which each of the tabs 420a, 420b, 420c, 420d are positioned spaced from the corners of the resonant panel 410. The inventors have realized that by arranging the tabs slightly spaced from the corners of the resonant panel, for example at least 10 millimeters from the corners of the resonant panel, the resonant panels 410, and indeed the assembled loudspeakers 400 can be transported with a reduced risk of damage to the tabs 420a, 420b, 420c, 420d. Since a correct location and shape of the tabs 420a, 420b, 420c, 420d is typically important for the accurate mounting of the loudspeaker 400 in the mounting surface, it is important that the tabs 420a, 420b, 420c 420d are not damaged in transit.

(37) FIGS. 5A to 5C are respective perspective, plan and side view illustrations of the tab 420a, shown in isolation. Each of the other tabs 420b, 420c, 420d of the flat panel loudspeaker 400 described with reference to FIG. 4 are substantially similar. As described previously in respect of the tab 120a of FIG. 2, the tab 420a has defined therein a through-recess 470. The through-recess 470 is provided in a distal portion 415 of the tab 420a. The through-recess 470 has a circular boundary forming a hole. The boundary is to engage with a headed fastener, such as a screw or a nail, to secure the tab 420a to the mounting surface during mounting. The tab 420a is connected to the support frame 440 at a proximal portion 416 of the tab 420a, in particular at an inner edge 428 of the tab. The inner edge 428 is provided at an opposite end of the tab 420a to the through-recess 470.

(38) The through-recess 470 is tapered in a through-direction of the tab 420a, thereby comprising a countersunk hole, such that the diameter D3 of the recess 470 at a front surface of the tab 420a is larger than the diameter D4 of the recess 470 at the rear surface of the tab 420a. The rear surface is the surface that is engageable with the mounting surface during mounting of the flat panel loudspeaker 400. This allows the head of the headed fastener inserted into the recess to sit flush with the tab. In this particular embodiment, a surface of the recess 470 at the rear surface of the tab 420a is configured to define a cutting portion to cut into an outer skin of the mounting surface when the rear surface of the tab 420a is provided against the mounting surface. In this way, the tab 420a can puncture through the outer skin of the mounting surface, ensuring that the portion of the tab 420a defining the through-recess 470 can act to at least partially crush an internal structure of the mounting surface below the outer skin. This further ensures that the tab 420a sits substantially flush with the mounting surface when mounted.

(39) The tab 420a in this embodiment is formed from sheet metal, for example steel, which may be stainless steel, and is thin to minimize the number of layers of plaster that are required to cover the tab 420a to make the tab 420a appear invisible in the mounting surface once the loudspeaker 400 is mounted. It will be understood that the tab 420a could be formed from other materials, such as carbon fiber. The tab 420a could be made in one piece integrally formed with the resonant panel and/or the support frame.

(40) In one example, the through-recess 470 is formed by a punching process. The punching process is further illustrated with reference to FIG. 6A to 6F, as will be described hereinafter. In particular, the through-recess 470 can be formed in a two-stage punching process. In a first stage of the punching process, a first punch tool 610 as shown in FIG. 6A and having a first taper angle is provided adjacent a tab blank 620. The tab blank 620 is formed from sheet metal, and will become the tab as described hereinbefore, following the completion of the manufacturing process. As shown in FIG. 6B, the first punch tool 610 is lowered through the tab blank 620 into a first punch receiver 612 to pierce the tab blank 620 and subsequently separated from the tab blank 620 to reveal a first tab blank opening 622, as shown in FIG. 6C. The first punch receiver 612 has defined therein a first punch tool opening sized to be just larger than the first punch tool 610 for receiving the first punch tool 610 therein. In this way, an edge of the first tab blank opening 622 will not be deformed inwardly during piercing of the tab blank 620 by the first punch tool 610. As can be seen, the first taper angle of the first punch tool 610 can be substantially zero; in other words, the first punch tool 610 does not taper and maintains a substantially constant thickness at a punch tip of the first punch tool 610. The first punch tool 610 typically defines a circular cross-section configured to punch a circular opening in the tab blank 620 to form the first tab blank opening 622.

(41) In a second stage of the punching process, as shown in FIG. 6D, the first punch tool 610 and the first punch receiver 612 are replaced by a second punch tool 630 and a second punch receiver 632. The second punch tool is provided with a punch tip 634 having a second taper angle, greater than the first taper angle; in other words, the punch tip 634 of the second punch tool 630 tapers towards the punch tip more than the first punch tool 610. The second punch receiver 632 has defined therein a second punch tool opening 636, larger than a footprint of the punch tip 634 of the second punch tool 630. The footprint of the punch tip 634 of the second punch tool 630 is typically substantially similar to a footprint of the punch tip of the first punch tool 610. In this example, the footprint of the punch tip 634 of the second punch tool 630 is smaller than the footprint of the punch tip of the first punch tool 610, such that the punch tip 634 of the second punch tool 630 can fit within the first tab blank opening 622 created by the first punch tool 610. As shown in FIG. 6E, the second punch tool 630 is lowered a predetermined amount into contact with the tab blank 620 to deform a boundary of the first tab blank opening 622, whereby to form the tab opening 624 shown in FIG. 6F. It will be understood that because the second punch tool opening 636 is wider than the punch tip 634 of the second punch tool 630, the boundary of the first tab blank opening 622 is able to deform with the direction of movement of the second punch tool 630 against the tab blank 620. Typically, the second punch tool 630 has a substantially circular cross-sectional profile, whereby to form a substantially circular tab opening 624 in the tab blank 620. As described hereinbefore, forming the tab opening 624 in this way ensures that a boundary of the tab opening can cut into the mounting surface, for example plasterboard, to substantially crush at least a portion of the mounting surface immediately adjacent to a skin layer, allowing the mounting tab to be engaged substantially flush with the mounting surface.

(42) It will be understood that the mounting tabs described herein can be used for mounting substantially any apparatus in an opening in a mounting surface, for the advantages described hereinbefore.

(43) Returning to FIGS. 4 and 5A to 5C, the tab 420a has a thickness of less than 5 mm, for example less than 3 mm, for example less than 2 mm, for example less than 1 mm, for example, approximately 0.8 mm. The tab 420a has a thickness of at least 0.2 mm so that the tab 420a is sufficiently sturdy to remain attached to the rest of the flat panel loudspeaker 400 during mounting, and to engage with the mounting surface without being substantially deformed.

(44) It has been found that in particular where a tab is made from stainless steel, it can be difficult to adhere a plaster skim onto the relatively large flat area of the proximal portion, such as the proximal portion 216 of the tab 120a of FIG. 2. It has also been found to be important to space the through-recess 210 and associated fastener as far as practical from the cut edge of the opening in the mounting surface, to mitigate against cracking and damage to the materials at the cut edge. Adhesion of the plaster to the tab 120a over the distal portion 215 will be enhanced by the presence of the fastener head within the countersunk through-recess 210, such as a driver head interface, into which the plaster skim would fill to provide some mechanical interconnection. However, for a tab where the distance from the inner edge 220, 428 to the outer edge 221, 429 is about 25 mm, the distance from the inner edge 428 to the center of the through-recess 470 may be 17 mm, providing a good lateral spacing of the fastener from the cut edge. In such a tab, for a through-recess of 4 mm diameter, the length of the distal portion 216, 416, defined as the region extending from the inner edge 220, 428 to the inner edge of the through-recess 210, 470 will be about 15 mm, which is a relatively large flat area that may be prone to the plaster skim over it cracking.

(45) Providing one or more surface features can therefore enhance the plaster adhesion to the proximal portion 216, 416. To this end, at least one perforation 450 in the form of an array of holes 450 is provided in the proximal portion 416 of the tab 420a of this embodiment. In use, a skim of plaster as applied to the tab 420a will cover the proximal portion 416, filling the holes 450. Once the plaster skim has set, the quantity of plaster filling the holes 450 will act as a mechanical connection between the skim layer and the surface of the tab 420a. An array of holes 450 is just one convenient way to enhance the plaster adhesion and it will be understood that other surface features, for example in the form of one or more partial recesses might be used instead for a similar purpose, although perforations 450 from one surface of the tab 420a to the opposite surface will mean that the plaster forms support columns all the way through the thickness of the tab 420a.

(46) The tab 420a includes a support foot 460 extending proximally of the inner edge 428, in a plane parallel to the plane of the proximal and distal portions 416, 415 of the tab 420a and spaced therefrom by the inner edge 428. The support foot 460 is held between the support frame 440 and the resonant panel 410.

(47) As well as the aesthetic and structural benefits of avoiding cracking in the plaster in the region above the tab 420a, an additional benefit of the perforations 450 is that it they also help to avoid any voids behind the plaster skim by allowing the plaster to flow through the perforations to the other side of the tab 420a, thereby filling any cavities or voids on that side. As well as additional structural integrity, this may prevent unwanted resonant effects that might otherwise have arisen due to the presence of voids in proximity to the loudspeaker 400.

(48) The loudspeaker 100, 300, 400 is mounted by making an opening in a mounting surface wherein the opening is sized to fit the resonant panel 110, 310; 410 and the loudspeaker 100, 300, 400 therein. The loudspeaker 100, 300, 400 is inserted into the opening until the at least one tab 120a-d, 320a-d, 420a-d is pushed against the mounting surface and the resonant panel 110, 310, 410 is substantially flush with the mounting surface. The loudspeaker 100, 300, 400 is then secured in the mounting surface by means of the at least one tab 120a-d, 320a-d, 420a-d or by another securing means. The opening is sized to be large enough for the resonant panel 110, 310, 410, support frame 140, 340, 440 and mounting unit 150, 350 to fit within the opening, but small enough that the tabs 120a-d, 320a-d, 420a-d also do not pass into the opening, and instead engage with the mounting surface. The opening is deep enough for the resonant panel 110, 310, 410, support frame 140, 340, 440, exciter and mounting unit 150, 350 to pass within the opening without the rear of the loudspeaker 100, 300, 400 touching the rear of the opening. For example, for a flat panel loudspeaker of dimensions (not including the at least one tab) of 45×20×7 cm, the opening in the mounting surface could be 47×21×10 cm, or 48×22×15 cm. It will be understood that these dimensions are just examples and the size of the opening is not limited to these numbers or proportions.

(49) In some examples, the at least one tab 120a-d, 320a-d, 420a-d can be configured to be removable from the loudspeaker 100, 300, 400 after the loudspeaker 100, 300, 400 is mounted in the mounting surface. The inventors have realized that when the loudspeaker 100, 300, 400 is inserted into the opening until the at least one tab 120a-d, 320a-d, 420a-d is pushed against the mounting surface and the resonant panel 110, 310, 410 is substantially flush with the mounting surface, the loudspeaker 100, 300, 400 can be adequately secured in the mounting surface by insertion of adhesive, or even plaster between the edge of the loudspeaker 100, 300, 400 and an internal edge of at least a portion of the opening in the mounting surface, for example at two opposing edges of the loudspeaker 100, 300, 400. In this example, the at least one mounting tab 120a-d, 320a-d, 420a-d may not include any through-recesses 470 as it may be intended that the mounting tab(s) 120a-d, 320a-d, 420a-d will be removed from the loudspeaker 100, 300, 400 before the loudspeaker 100, 300, 400 is plastered over in the mounting surface. The at least one mounting tab 120a-d, 320a-d, 420a-d can be configured to be detachably secured to the loudspeaker 100, 300, 400. In another example, the at least one mounting tab 120a-d, 320a-d, 420a-d can be configured to be frangibly secured to the loudspeaker 100, 300, 400. In this way, the at least one mounting tab 120a-d, 320a-d, 420a-d can be easily removed from the loudspeaker 100, 300, 400 once the loudspeaker 100, 300, 400 is correctly positioned flush in the mounting surface. It will be understood that the skilled person will be aware of a number of different means and methods by which the at least one tab 120a-d, 320a-d, 420a-d can be removably attached to the loudspeaker 100, 300, 400, for example to the support frame 140, 340, 440 or to the mounting unit 150, 350. In some examples, the at least one tab 120a-d, 320a-d, 420a-d can be removably attached directly to the resonant panel 110, 310, 410 and configured to be removed from the resonant panel once the loudspeaker 100, 300, 400 is positioned in the mounting surface.

(50) In summary, there is provided a flat panel loudspeaker (100, 300, 400) for mounting in an opening in a mounting surface. The flat panel loudspeaker comprises a planar resonant panel (110, 310, 410) insertable into an opening in the mounting surface and having a front surface, the front surface to face outwardly in the mounting surface when the flat panel loudspeaker is mounted in the mounting surface, and the resonant panel further having a rear surface opposite the front surface. The loudspeaker further comprises an exciter coupled to the rear surface of the resonant panel to cause the resonant panel to vibrate on operation of the exciter, to generate sound. The loudspeaker additionally comprises a support frame (140, 340, 440) for mounting in the mounting surface and having the rear surface of the resonant panel fixed thereto around substantially the whole of the outer boundary of the resonant panel, such that when mounted in the mounting surface and when the resonant panel is caused by the exciter to vibrate on operation of the exciter, the outer boundary of the resonant panel is fixed relative to the mounting surface. The loudspeaker also comprises at least one tab (120a-d, 320a-d, 420a-d), configured to extend away from the support frame in a tab direction parallel to the mounting surface and substantially flush with the front surface of the resonant panel when the loudspeaker is to be mounted in the mounting surface, whereby to keep the front surface of the resonant panel substantially flush within the mounting surface when the tab is against the mounting surface.

(51) Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to (and do not) exclude other components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

(52) Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The disclosure extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.