Acoustic technique for room, such as music hall, changeable between sound absorption state and sound reflection state

Abstract

The invention relates to a panel for attachment to a boundary of a room, such as a music hall, comprising: a panel (1, 28) provided with a through-opening (2, 29) between a first surface (1 ', 28') and a second surface (1 '', 28 '') of the panel (1, 28); a closing unit (3, 14, 30), the closing unit is arranged opposite and facing the second surface (1 '', 28 '') of the panel (1, 28) such that a distance between the second surface (1 '', 28 '') of the panel (1, 28) and the closing unit (3, 14, 30) can be varied between a closed state in which the closing unit (3, 14, 30) closes the through-opening (2, 29) in the panel (1, 28) and an open state in which the closing unit (3, 14, 30) closes the through-opening (2, 29) in the panel (1, 28). The closing unit (3, 14, 30) does not close the through-opening (2, 29) in the panel; the closing unit (3, 14, 30) is substantially acoustically impermeable in a first region (15, 32) of the closing unit covering the through-opening (2, 29) in the panel (1, 28) in the closed state of the panel such that sound is substantially prevented from being transmitted through the through-opening (2, 29) in the panel (1, 28) in the closed state 15 of the panel; and, in one or more second regions (4, 12, 13, 17, 37, 38) of the closing unit (3, 14, 30) that do not completely coincide or partially coincide with the through-opening (2, 29) in the panel (1, 28) in the closed state of the panel, the closing unit (3, 14, 30) allows sound to be transmitted through the closing unit. The invention also relates to a device comprising a panel according to the invention and to a system of such a device.

Description

Technical Field

[0001] The present invention relates generally to the field of acoustic covering devices and corresponding systems for the boundaries of rooms, in particular for concert halls and auditoriums, and more particularly to devices and systems that can be changed between a state in which they absorb sound energy and a state in which they reflect sound energy, and that have mechanisms allowing the possibility of gradual change of such devices and systems between these two states. Background Art

[0002] In concert halls, it is highly desirable to be able to change the reverberation time (RT), as different types of music require different reverberation times to achieve the best sound quality, such as an orchestra or singer performing in the hall. In the low frequency band, especially the 125 Hz band, it is preferred to reduce the reverberation time by about 40% or more.

[0003] Concert halls usually have a large volume and, according to the Sabine formula, a 40% reduction in reverberation time requires that a very large area of the hall's borders be covered with variable acoustic surfaces that can respectively reflect and absorb the sound.

[0004] In the prior art, acoustic panels or modules with variable sound absorption properties have been disclosed, none of which, except those submitted by the inventors, have proven successful for concert halls. Some of the prior art has further proven to be too expensive for such large surface areas for the budget of concert halls.

[0005] An example of prior art capable of significantly varying the low-frequency reverberation time of a hall is disclosed in the applicant's own prior patent application WO 2018 / 162014 A1. The modules and module systems disclosed therein are well-suited for rooms designed, for example, for psychoacoustic listening tests, which are typically much smaller than concert halls and therefore require a much smaller number of panels (modules). However, while this solution is acoustically very suitable, it is quite expensive for concert halls.

[0006] Purpose of the present invention

[0007] Based on the above background, an object of the present invention is to provide a technology comprising panels configured for use in devices and systems designed to vary the reverberation time of a concert hall, which technology is simpler and less expensive to manufacture, maintain and replace than the panels or modules of the prior art, so that the costs associated with the procurement, installation and maintenance of panels of very large areas, as well as the need for their replacement, can be kept at a reasonable level.

[0008] Definitions of terms used below

[0009] The terms "technology," "board," "device," and "system" are used in the following description and claims. As used herein, these terms are defined as follows:

[0010] The term "technology" includes both boards, devices and systems, as well as the methods of using these physical entities.

[0011] Terminology: A "device" refers to a physical entity that can absorb or reflect sound energy, at least within a given frequency range. The device can be in a state in which it does not absorb sound energy (hereinafter referred to as the "closed state"), or in a state in which it absorbs sound energy (hereinafter referred to as the "open state"). In the open state, the device can be more or less open up to a certain maximum open state, and if desired, the transition from the fully closed state to the maximum open state can be gradual or in steps, thereby varying the degree of sound absorption in the open state.

[0012] The "device" includes a "panel" that can be in a closed state, in which acoustic energy cannot propagate through the panel, or in a more or less open state, in which acoustic energy can propagate through the panel to a certain extent, the extent of which can be controlled within certain limits. The device also includes opening and closing means configured to change the sound propagation state through the panel, and operating means configured to actuate the opening and closing means. The device also includes sound absorbing means capable of absorbing at least some of the acoustic energy propagating through the panel in the open state.

[0013] A "system" comprises a plurality of "devices" or "panels", wherein the system is configured to be mounted on selected boundaries of a room, for example, on a wall and / or ceiling. The system may also comprise a drive mechanism configured to operate the operating means of the devices or panels as described above between a closed state and a more or less open state. Summary of the Invention

[0014] The above and further objects and advantages are obtained by the panel and the system of panels according to the present invention.

[0015] According to the present invention, a technology for varying the reverberation time of a large room with extensive wall and / or ceiling areas designed for performing different types of music is provided. The simplicity and low production costs of this technology, compared to the module disclosed in the applicant's prior application WO 2018 / 162014 A1, are achieved, among other advantages, by reducing the number of hinges and other complex mechanical components in the panel. Thus, according to the present invention, for example, the four closing members and the corresponding twelve hinges described in the above-mentioned examples of the prior art are reduced to a single closing unit and one or only a few hinges (or similar mechanical structures). Furthermore, by using a large-scale platform as the actual facade of the structure, a technology is provided that meets the desire to provide a simpler and therefore cheaper solution to the problem of providing the desired variability in reverberation time while simultaneously achieving an aesthetically pleasing appearance for, for example, the boundary of a concert hall equipped with the panel according to the present invention.

[0016] According to a first aspect of the present invention, there is provided a panel for attachment to a boundary of a room, such as a concert hall, the panel comprising:

[0017] - a panel, the panel being provided with a through opening between the first surface and the second surface of the panel;

[0018] a closing unit arranged opposite to and facing the second surface of the panel so that the distance between the second surface of the panel and the closing unit can be varied between a closed state, in which the closing unit closes the through opening in the panel, and an open state, in which the closing unit does not close the through opening (2, 29) in the panel;

[0019] -in,

[0020] - in a first region of the closing unit covering the through-opening in the panel in the closed state of the panel, the closing unit is substantially acoustically impermeable, so that in the closed state of the panel, sound is substantially prevented from being transmitted through the through-opening in the panel;

[0021] In one or more second regions of the closing unit which do not completely coincide or partially coincide with said through-opening in the panel in the closed state of the plate, the closing unit is configured to allow sound to be transmitted through the closing unit.

[0022] In a preferred embodiment of the first aspect, the panel comprises only a single closing unit configured to open and close all through openings in the panel.

[0023] In an embodiment of the first aspect, the closing unit is provided with a through opening which is displaced relative to the through opening in the panel so that when the plate is in the closed state, the through opening in the closing unit does not overlap with the through opening in the panel.

[0024] According to the present invention, the through opening is provided in the closing unit in order to facilitate the transmission of sound to the sound-absorbing material or other sound-absorbing device provided behind the closing unit in the absorption (open) state of the panel, thereby improving the efficiency of the device in the open state by significantly improving the absorption.

[0025] In embodiments of the first aspect, the change between the closed state of the panel and the open state of the panel occurs gradually, and allows the panel to be in a fully closed state or a fully open state (or a maximum open state, as determined by the specific design of the panel) or in any one or more intermediate states, such as a half-open state. Thus, in this embodiment, the transmission of sound from one side (front) of the panel and from the opposite (rear) side of the panel to the sound absorbing material or sound absorbing device through the through openings in the panel can gradually vary between substantially no sound transmission and maximum sound transmission, including many intermediate degrees or any intermediate degrees of sound transmission through the panel that intentionally affect the absorption curve of the device in the open state.

[0026] In an embodiment of the first aspect, the closing unit is pivotably attached to the panel such that when the closing unit is pivoted relative to the panel, the closing unit switches the panel between the closed state and the open state.

[0027] In an embodiment of the first aspect, one longitudinal end of the closing unit is pivotally linked at one or more points near the circumference of the panel by a hinge member or similar mechanical device.

[0028] In an embodiment of the first aspect, the closing unit is offset or tilted from the through opening of the panel to further improve high frequency absorption.

[0029] In an embodiment of the first aspect, one longitudinal end of the closing unit is pivotably linked to a corresponding longitudinal end of the panel by a hinge member or similar mechanical device.

[0030] In an embodiment of the first aspect, the panel is configured such that the closing unit can be displaced substantially parallel to the second surface of the panel, such that the closing unit can be displaced a distance between a position where the closing unit closes the through opening in the panel and a position where the closing unit opens the through opening in the panel. This displacement can also occur gradually.

[0031] In an embodiment of the first aspect, a permanent magnetic device is arranged around the through opening on the second surface of the panel, and the closing unit is made of or equipped with a material that can be attracted by the magnetic device (at least in the area corresponding to the position of the permanent magnet), so that when the panel is in a closed state, the magnetic device keeps the closing unit in sound-tight contact with the second surface of the panel.

[0032] In an embodiment of the first aspect, an electromagnetic device is arranged around the through opening on the second surface of the panel, and the closing unit is made of a material that can be attracted by the magnetic device (at least in the area corresponding to the position of the electromagnet), so that when the panel is in a closed state, the magnetic device keeps the closing unit in sound-tight contact with the second surface of the panel.

[0033] In an embodiment of the first aspect, the magnetic means is supplemented by a rubber gasket or a gasket made of another suitable flexible / compressible material to ensure an acoustically tight closure.

[0034] In an embodiment of the first aspect, a first mechanical device is arranged around the through opening on the second surface of the panel, and a corresponding second mechanical device is provided on the closing unit (at least in an area corresponding to the position of the mechanical device), and the second mechanical device is configured to remain engaged with the first mechanical device so that when the panel is in a closed state, the mechanical device keeps the closing unit in sound-tight contact with the second surface of the panel.

[0035] In an embodiment of the first aspect, the mechanical means are supplemented by a rubber gasket or a gasket made of another suitable flexible / compressible material to ensure an acoustically tight closure. In an embodiment of the first aspect, mechanical engagement means are provided on the second surface of the panel around the through opening, and wherein, at least in an area corresponding to the location of the mechanical engagement means, the closing unit is provided with cooperating releasable mechanical engagement means such that, in the closed state of the panel, the mechanical engagement means maintains an acoustically tight contact between the closing unit and the second surface of the panel.

[0036] In an embodiment of the first aspect, the closing unit is a single plate provided with a through opening.

[0037] In an embodiment of the first aspect, the closure unit comprises a plurality of independent closure members or panels, wherein adjacent closure members or panels are separated from each other by a gap having a width w, thereby forming a through-opening in the closure unit. In this embodiment, the adjacent panels are interconnected connecting members. In an embodiment of the first aspect, the panel is provided with a facing sheet or other visually attractive surface sheet on the first surface, the sheet being provided with through-openings corresponding to the through-openings in the panel, so that sound from the environment in front of the facing can propagate through the through-openings in the facing and the corresponding through-openings in the panel and reach the sound absorbing material provided in the space between the panel and the boundary portion of the room.

[0038] In an embodiment of the first aspect, the panel comprises actuator means, such as an electric motor, configured to move the closing unit between the open and closed conditions of the panel.

[0039] In an embodiment of the first aspect, in the closed state of the panel, in at least some areas coinciding with the through openings in the panel, the closing unit is provided with an element extending from the surface of the closing unit and facing the panel, and the element is configured such that: when the panel is in the closed state, the element extends through at least some of the through openings in the front panel and extends a distance in front of the front panel.

[0040] According to a second aspect of the present invention, there is provided an apparatus for changing the reverberation time (RT) of a room, such as a concert hall, wherein the apparatus comprises:

[0041] - a panel according to the first aspect;

[0042] a sound absorbing device, such as a sound absorbing material, arranged so that the closing unit can control the transmission of sound energy from the surroundings of the device to the sound absorbing device;

[0043] - attachment means configured to attach the panel to a border of the room such that a space is formed between the panel and the border, in which space the sound absorbing device is arranged; and

[0044] - an operating device configured to open or close the closing unit, and

[0045] - a surrounding device which prevents the sound energy from reaching the absorption device when the device is in the closed state.

[0046] According to a third aspect of the present invention, there is provided an acoustic covering system for a boundary portion of a room, wherein the system comprises:

[0047] - one or more sound absorbing devices according to the second aspect;

[0048] Actuator means, for example an electric motor, configured to drive an operating device of the device between an open and a closed state of the panel or vice versa.

[0049] According to an embodiment of the third aspect, the actuator is configured to maintain the closing unit of the panel in one or more states between a fully closed state and a maximally open state of the closing unit.

[0050] The present invention provides an acoustic technology which has the very important advantage of being cheaper to manufacture, maintain, repair or replace than the prior art mentioned in the background of the invention.

[0051] Furthermore, the present invention provides an acoustic technique that allows the reverberation time of a room to be varied to a significant degree, particularly (but not exclusively) at low frequencies, so that the room or other space in which the inventive technique is installed can be adapted to a wide range of different acoustic requirements. Thus, for example, in an arena used for both sporting events and amplified concert performances, the reverberation time for sporting events may be relatively long, while the reverberation time for amplified musical performances may be relatively short.

[0052] In order to ensure the best performance of the acoustic technology according to the invention, the panels and closing units must have a high mass per unit area. This makes HDF products such as fiber cement and ROCKWOOL It is very suitable for this purpose. In addition, a metal plate (such as a steel plate) can be attached to the rear surface of the MDF board to increase its mass per unit area.

[0053] In an embodiment of the present invention, both the panel and the closing unit may have an arched form so that the sound impacting the front surface of the panel (or impacting the facing sheet attached to the front surface of the panel) becomes diffuse; especially in the reflective (i.e. closed) state of the panel of the present invention.

[0054] Therefore, the above-mentioned prior art described in the background of the present invention uses a number of closing units, each of which is provided with a number of hinges in each panel (4 closing units, with a total of 12 hinges), and these hinges are expensive to manufacture and install. In this prior art, the dimensions of the panels are typically 2.4m x 0.6m, thus having a 1.44m 2 Therefore, the coverage area is 1.44m 2 The area requires the use of 4 closing units and 12 hinges of the preferred embodiment of the prior art.

[0055] If one wishes to use a relatively large panel of the prior art, it should be provided with a correspondingly greater number of through-openings, and for each through-opening a closing plate should be provided, each closing plate having, for example, two to three hinges. For example, if the area of the panel is doubled, it is necessary to use twice as many closing plates and twice as many hinges. Thus, instead of four closing plates with a total of 12 hinges, eight closing plates with 24 hinges must be used. By applying the present invention, the corresponding area can be covered by only one closing unit with a few (one to three) hinges, which makes the production of the panel considerably cheaper.

[0056] Furthermore, with the system according to the invention, maintenance is less complex and less expensive, since the actuators for driving the system of a single row of panels at a certain location in the hall can be provided and easily accessible, without, for example, having to completely or at least partially remove the seats in the hall. This is particularly important for the system according to the invention provided at the ceiling of the hall. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Further benefits and advantages of the present invention will become apparent upon reading the detailed description of non-limiting exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which:

[0058] Figure 1 a and Figure 1 b shows a schematic front view and a side view of a panel according to an embodiment of the present invention;

[0059] Figure 2 a and Figure 2 b shows the Figure 1 Schematic front and side views of a panel according to an embodiment of the present invention are shown, wherein the panel is mounted on a wall of a room so that a space is formed between the panel and the wall, and a sound absorbing material is disposed in the space;

[0060] Figure 3 shows a schematic side view of a panel according to an embodiment of the present invention mounted on a wall, in which embodiment a closing unit is pivotally connected to the panel so that the closing unit can be pivoted between a closed state, in which sound cannot propagate from the surroundings through the through opening in the panel and cannot reach the sound absorbing material, and an open state, in which sound can propagate through the through opening in the panel and can reach the sound absorbing material;

[0061] Figure 4shows a schematic side view of a panel according to another embodiment of the present invention mounted on a wall, in which embodiment a closing unit is connected to the panel in a displaceable manner such that the closing unit can be displaced substantially parallel to the panel, whereby the closing unit can be moved between a closed state, in which sound cannot propagate from the surroundings through the through opening in the panel and cannot reach the sound-absorbing material, and an open state, in which sound can propagate through the through opening in the panel and reach the sound-absorbing material;

[0062] Figure 5 An embodiment of the present invention is shown, in which the closing unit is provided with the same Figure 1 and Figure 2 The pattern of through openings of the illustrated embodiment is different from the pattern of through openings;

[0063] Figure 6 An alternative embodiment of a closing unit according to the invention is shown;

[0064] Figure 7 shows a schematic diagram of an embodiment of a system provided with drive and actuator means according to the invention;

[0065] Figure 8 shows a schematic perspective view of a panel and a closing unit, illustrating some of the essential features of the invention;

[0066] Figure 9 A perspective view of a mechanism configured to move a closing unit between an open state and a closed state or between a closed state and an open state in a manner generally parallel to a panel is shown;

[0067] Figure 10 A surrounding device is shown which prevents acoustic energy from reaching the absorbing device in the closed state of the device;

[0068] Figure 11 shows another embodiment of a panel according to the invention, which panel causes a diffusion of the sound field outside the panel when the panel is in the closed state of the panel; and

[0069] Figure 12 Two non-limiting examples of plates provided with outwardly extending diffusing elements according to the invention are shown. DETAILED DESCRIPTION

[0070] The principles of the present invention will be described by various embodiments of the present invention. However, it should be understood that those skilled in the art may conceive other embodiments than those shown and described in the detailed description of the present invention, and the scope of the present invention is defined by the independent claims.

[0071] refer to Figure 1 a and Figure 1 b, shows a schematic front and side view of a panel according to an embodiment of the invention, generally designated by reference numeral P, wherein the panel comprises a panel 1, for example made of fibrous gypsum. In the embodiment shown, the panel 1 is planar and Figure 1 The panel 1 shown in a extends in and around the (x, y) plane, wherein the first face 1' of the panel extends in the (x, y) plane. The panel 1 accordingly comprises a first surface 1' and a second surface 1", which may be alternately referred to as a front surface 1' and a rear surface 1", respectively.

[0072] The panel 1 is provided with a pattern of through openings 2 which in the embodiment shown are generally of rectangular cross-section. However, it will be appreciated that any shape and pattern of panels, through openings in the panels and other closing elements having the essential features of the invention may be used.

[0073] In some embodiments of the present invention, a facing sheet is provided on the first surface 1' of the panel 1, the facing sheet having through-openings corresponding to the through-openings in the panel. This sheet can provide the panel 1 with an aesthetically pleasing appearance when viewed from a space S1 in front of the first surface 1', thereby adapting the panel's appearance to suit its use in, for example, different concert halls or auditoriums. Any desired surface appearance can be used.

[0074] According to the present invention, the through opening 2 in the panel 1 can be opened and closed so that sound can propagate through the through opening 2 or sound can be effectively prevented from propagating through the through opening 2. This means that the panel according to the present invention can be in an open state, in which sound can propagate through the through opening 2, or in a closed state, in which sound cannot propagate through the through opening 2. For this purpose, the panel is provided with a closing unit 3, which is Figure 1 a and Figure 1 In the embodiment shown in b, the closing unit 3 is pivotally attached to the panel 1 at one longitudinal end portion 1'' of the panel 1 by a hinge member 5. The closing unit 3 can pivot by an angle α relative to the second surface 1'' of the panel 1 between the open state and the closed state of the panel.

[0075] According to the present invention, the closing unit 3 is provided with a pattern of through openings 4, which are arranged relative to the Figure 1 The through opening 2 in the panel 1 shown in (a) is displaced so that the through opening 4 in the closing unit 3 does not overlap with the through opening 2 in the panel 1 when the panel is in the closed state.

[0076] Providing the closing unit 3 with a through opening 4 has a very important consequence, namely that the angle α of the plate in the open state can be very limited (much smaller than Figure 1 (b) and still ensure that sound energy is adequately transmitted through the panel when the panel is open. Figure 3 is shown in (also in Figure 4 ), in which the pivoting movement of the closing unit 3 is replaced by a displacement indicated by d. With a smaller angle α or a smaller plate depth d, the overall construction depth of the plate becomes smaller, thus saving expensive space.

[0077] Reference Figure 2 a and Figure 2 b, shows schematic front and side views of an apparatus generally indicated by reference numeral D according to an embodiment of the present invention, comprising Figure 1 The panel shown, wherein the panel is mounted on the wall 9 of the room so that a space S2 is formed between the panel 1 and the closing unit 3, and the sound further propagates through the through opening 4 in the closing unit 3 and reaches the space S3, in which the sound absorbing material 8 is provided, and then a certain amount of sound energy is absorbed into the sound absorbing material 8.

[0078] therefore, Figure 2 (a) and Figure 2 (b) shows a method of Figure 2 (b) shows a device that changes between an open state (shown in FIG. 1 ) and a closed state, in which sound is absorbed by the device, and in which the sound is reflected by the first (or front) surface 1' of the panel 1. Therefore, the device comprises: a panel according to the present invention; suitable attachment means 7, the attachment means 7 being configured to attach the panel to a boundary portion 9 of a room; and sound-absorbing material 8 or other sound-absorbing means or devices disposed in the space formed between the panel 1 and the boundary portion 9. The device may also be provided with an operating device configured to open and close the panel, but an operating device configured to open and close multiple panels or devices according to the present invention may also be employed.

[0079] Figure 3 and Figure 4 A device according to the invention is shown, comprising a panel according to the invention mounted on a wall 9 at a short distance W from the wall 9 by means of attachment means 7. Mounting the panel 1 as close as possible to the wall 9 - or to another boundary of the room - is very important, for example in a concert hall, where a large number of devices (possibly hundreds of devices) must be used, and a deep panel (large W) would therefore result in a considerable reduction in the space available in the hall after the devices have been installed.

[0080] refer to Figure 3, shows a schematic side view of a device mounted on a wall 9 according to an embodiment of the present invention, in which the closing unit 3 is pivotably connected to the panel 1, as indicated by the angle α, so that the closing unit 3 can be pivoted between a closed state, in which sound cannot propagate from the surroundings S1 through the through opening 2 in the panel 1 and reach the sound-absorbing material 8, and an open state, in which sound can propagate through the through opening 2 in the panel 1 and reach the sound-absorbing material 8. In this embodiment, the panel 1 is mounted on the attachment device 7 at a distance W from the wall 9, so that the depth W of the panel is limited only by the requirement to provide a sufficient acoustic path between the surroundings S1 and the sound-absorbing material 8 in the open state of the panel.

[0081] refer to Figure 4 , shows a schematic side view of a device mounted on a wall 9 according to another embodiment of the present invention, in which embodiment, the closing unit 3 is connected to the panel in a displaceable manner as indicated by arrow d, so that the closing unit 3 can be displaced substantially parallel to the panel 1, whereby the closing unit 3 can move between a closed state and an open state, in which, sound cannot propagate from the surrounding environment S1 through the through opening 2 in the panel 1 and cannot reach the sound-absorbing material 8, and in the open state, sound can propagate through the through opening 2 in the panel 1 and reach the sound-absorbing material 8.

[0082] refer to Figure 5 , shows a front view of an embodiment of the present invention, wherein the closing unit 3 (not visible) is provided with the same Figure 1 and Figure 2 The pattern of the through openings 12 of the embodiment shown in FIG is different from the pattern of the through openings 12. The through openings in the panels and closing units may have any shape, form and pattern.

[0083] Reference Figure 6 , shows an alternative embodiment of a closing unit according to the present invention, generally indicated by reference numeral 14. The closing unit comprises a plurality (four in the figure) of closing members or plates 15, the dimensions of which are arranged so that they can close corresponding through openings in the panel. Adjacent closing members 15 are connected by connecting members 16 so that gaps 17 of width w are formed between adjacent closing members 15. In the embodiment shown, the closing unit 14 is attached to the panel (not shown) by hinges 19 so that the closing unit can undergo the above-mentioned combination Figure 2 (b) and Figure 3 It will be appreciated that the pivoting motion relative to the plate is described. Figure 6 The closure unit shown can be opened or closed in any manner, for example, by Figure 4The embodiment shown is opened or closed in a manner relative to the parallel displacement of the panels.

[0084] With reference to the prior art module described in WO 2018 / 162014 A1, the closing member 15 corresponds to the closing plates described in this document, wherein each of these closing plates is provided with a hinge 18 (e.g. Figure 6 (shown as a dotted line in FIG), a hinge 18 enables each closing panel to pivot relative to the front surface. Figure 6 As can be clearly seen in FIG, a plate with four through-openings in the front face would require a total of twelve hinges in the prior art module, this number being reduced to only two hinges in the embodiment of the closing unit 14 according to the invention.

[0085] Reference Figure 7 , shows a schematic and illustrative illustration of an embodiment of a system according to the present invention, generally indicated by the reference numeral 20. The system shown comprises two rows (row 1 and row 2) of panels 21 according to the present invention. Towards the second surface, rear surface 1 (see Figure 1 or Figure 2 ) views the system and schematically shows the corresponding closing unit 22.

[0086] The respective closing units 22 are driven by drive members 23 (for the panels in the first row) and 24 (for the panels in the second row). At their longitudinal ends, the drive members 23, 24 are attached to respective actuators 25, 26 that drive the movement of the corresponding closing units 22. If desired, the actuators 25, 26 can be provided in the form of an integral assembly, schematically indicated by reference numeral 27.

[0087] according to Figure 7 The system of the illustrated embodiment of the invention facilitates maintenance and / or replacement of the actuators because the actuators are not located within or at each individual panel 21, but are located at a location outside the system that is easily accessible without having to remove chairs, etc. from the room in which the panels are installed in order to access the actuators.

[0088] Reference Figure 8 , shows a schematic perspective view of a panel 28 and a closing unit 30 illustrating some basic features of the present invention. The panel 28 has a first surface 28 ′ and a second surface 28 ″, and is provided with a plurality of through openings 29 . The second surface 28 ″ faces the closing unit 30 .

[0089] The closing unit 30 has a first surface 30 ″ facing the plate second surface 28 ″ of the panel 28 and a second surface 30 ″ which in actual installation will face the sound absorbing material or other sound absorbing device.

[0090] As indicated by dashed lines 33, 34, 35, and 36, each through-opening 29 in the panel 28 corresponds to an area 32 on the closing unit 30 that is acoustically impermeable. In order for the closing unit 30 to acoustically close the through-opening 29 in the panel when the panel is in the closed state according to the invention, this area 32 must be at least as large (and have the same shape) as the corresponding through-opening 29. In actual implementation, a larger acoustically impermeable area 31 will be required to achieve the desired acoustic tightness.

[0091] According to the invention, substantially the entire remaining area of the closing unit 30, i.e. the area not covered by the area 31 or selected parts of this remaining area, is constructed so that sound can penetrate the closing unit in this area / areas. A practical example of this is shown in Figures 1 to 7 is shown in and described above. Figure 8 In the embodiment shown in FIG5 , such areas are provided by the slits 37, 38 in the closing unit 30, which, in the closed state of the panel, do not overlap with the through opening 29 in the panel. It will be appreciated that other configurations of acoustically permeable areas in the closing unit may also be used, as long as these areas do not overlap with any acoustically impermeable areas 31, 32 of the closing unit 30.

[0092] Reference Figure 9 (a), (b) and (c) in the accompanying drawings show a mechanism configured to move a closing unit 39 between an open state and a closed state or between a closed state and an open state in a manner generally parallel to a panel 40. The mechanism, generally designated by the reference numeral 39, includes a pair of brackets 45" and a pair of brackets 45". A corresponding pair of brackets 44 is attached to the closing unit, the brackets 44 connecting the closing unit to the mechanism so that the mechanism, when operated, can move the closing unit 41 between an open state and a closed state or between a closed state and an open state in a manner parallel to the panel 40. The mechanism 39 essentially includes an operating arm member 42 for each pair of brackets, the operating arm member 42 being operable by an actuator 48. The arm members of the pairs of brackets 45', 45" are connected by a longitudinally extending rod 43 so that a single actuator can operate both arm members 42. The arm member 42 is attached to a transverse shaft 46 that extends between the brackets 45', 45" of each corresponding pair of brackets. When the arm member 42 is pivoted under the action of the actuator 48, the shaft 46 rotates the plate member 49, as shown. Figure 9(b) shows a plate member 49 provided with a groove 47 in which a tab 44 attached to a respective bracket 45', 45" can be moved so that the shaft 46 can be rotated by a given angle determined by the length of the groove 47. The extension of the shaft 44 can be moved in the groove 50 perpendicular to the plane of the panel 40 so that the rotation of the shaft 46 causes the movement of the closing unit 41 relative to and parallel to the panel 40, as shown Figure 9 (b) shown.

[0093] It should be understood that alternatives may be used in addition to Figure 9 Other mechanisms than those shown are possible and would also fall within the scope of the present invention.

[0094] refer to Figure 10 , showing a surrounding device 51 which prevents the sound energy from reaching the absorbing device in the closed state of the device ( Figure 2 Indicated by reference numeral 8 in FIG. Figure 10 Not present in the picture shown). Sound energy must be prevented from entering through any means other than openings in the panel. Figure 2 The absorbent device 8 shown, therefore, needs to be surrounded on all sides by a top panel, a bottom panel and side panels or other covering means, such as Figure 10 shown.

[0095] refer to Figure 11 , shows a further embodiment of a panel according to the invention, in which the closing unit 56 is provided with extension elements 60, 61 on a surface 57 facing the rear surface 55 of the front panel 52, wherein each individual extension element is positioned and configured such that, in the closed state of the panel, the extension element 60, 61 passes through a corresponding through-opening 53 in the front panel 52 and extends in an outward direction by a distance d from the outer surface 54 of the front panel. When the panel is in the closed state, the presence of these outwardly extending elements leads to an ideal diffusion of the sound field outside the panel, i.e. in the room in which the panel according to the invention is installed.

[0096] The outwardly extending element may comprise two parts, namely an inner part 60 which, in the closed state of the panel, extends a distance d from the outer surface 54 of the panel 52 through a corresponding through opening in the panel 52, and an outer part 61 which is located at the outer end of the first part 60, so that the total extension outwardly from the outer surface 54 of the panel 52 is d T .

[0097] The dimensions and geometry of the inner and outer parts depend on the dimensions and shape of the corresponding through-openings 53 in the panel 52. Furthermore, the shape of the second part can be chosen so as to obtain the desired sound diffusion in the sound field in front of the panel as best as possible. Typically, the second part 61 can have the shape of a spherical cap.

[0098] Reference Figure 12 , shows two non-limiting examples of panel elements according to the present invention in plan view. These panels may or may not be provided with outwardly extending diffuser elements. According to the present invention, the respective closing units may also be provided with extension elements corresponding to some through-openings in the panel, but not to the remaining through-openings.

[0099] exist Figure 12 In a, the dimensions of panels 52' and 52" are 60 cm by 240 cm, but other dimensions may be used. Figure 12 A circular through opening 62 is used in Figure 12 In b, longitudinally extending rectangular through-openings 63 are used. As mentioned, extension elements for all, part, or no extension elements for the through-openings 62, 63 may be used.

Claims

1. A panel for attachment to a boundary of a room, such as a concert hall, comprising: - a panel (1, 28) provided with a through opening (2, 29) between a first surface (1', 28') and a second surface (1", 28") of the panel (1, 28); - a closing unit (3, 14, 30), said closing unit (3, 14, 30) being arranged opposite to and facing said second surface (1", 28") of said panel (1, 28), such that a distance between said second surface (1", 28") of said panel (1, 28) and said closing unit (3, 14, 30) is variable between a closed state, in which said closing unit (3, 14, 30) closes said through opening (2, 29) in said panel (1, 28), and an open state, in which said closing unit (3, 14, 30) does not close said through opening (2, 29) in said panel; - in a first region (15, 32) of the closing unit covering the through-opening (2, 29) in the panel (1, 28) in the closed state of the panel, the closing unit (3, 14, 30) is substantially sound-impermeable, so that in the closed state of the panel, sound is substantially prevented from being transmitted through the through-opening (2, 29) in the panel (1, 28); Wherein, in one or more second areas (4, 12, 13, 17, 37, 38) of the closing unit (3, 14, 30) which do not completely overlap or partially overlap with the through opening (2, 29) in the panel (1, 28) in the closed state of the plate, the closing unit (3, 14, 30) is configured such that the closing unit (3, 14, 30) allows sound to be transmitted through the closing unit in the area.

2. The panel according to claim 1, wherein The panel comprises only a single closing unit (3, 14, 30) configured to open and close all through openings (2, 29) in the panel (1, 28).

3. The panel according to claim 1 or 2, wherein: The closing unit (3) is provided with a through opening (4), and the through opening (4) is displaced relative to the through opening (2) in the panel (1), so that when the plate is in the closed state, the through opening (4) in the closing unit (3) does not overlap with the through opening (2) in the panel (1), thereby the closing unit (3) provides acoustic sealing for the through opening (2) in the panel (1).

4. A panel according to any one of the preceding claims, wherein The closing unit (3) is provided with an element extending from a surface of the closing unit facing the panel in at least some areas that coincide with the through openings in the panel (1, 28) in the closed state of the panel, and the element is configured so that: when the panel is in the closed state, the element extends through at least some of the through openings in the front panel and extends a distance (d) in front of the front panel.

5. A panel according to any one of the preceding claims, wherein The closing unit (3) is pivotably attached to the panel (1) such that when the closing unit (3) is pivoted relative to the panel (1), the closing unit (3) is able to change the plate between the closed state and the open state.

6. The panel according to claim 5, wherein One longitudinal end (3') of the closing unit (3) is pivotably attached to a corresponding longitudinal end (1'") of the panel (1) by means of a hinge member (5).

7. A panel according to any one of the preceding claims, wherein The plate is configured such that the closing unit (3) can be displaced in a manner substantially parallel to the second surface (1") of the panel (1), such that the closing unit can be displaced a distance (d) between a position in which the closing unit closes the through opening (2) in the panel and a position in which the closing unit opens the through opening (2) in the panel (1).

8. A panel according to any one of the preceding claims, wherein The closing unit is a single plate-shaped piece (3) provided with a through opening (4).

9. A panel according to any one of the preceding claims, wherein The closing unit (14) comprises a plurality of independent closing parts (15), wherein adjacent closing parts (15) are separated from each other by a gap (17) having a width (w), thereby forming a through opening in the closing unit (14).

10. A panel according to any one of the preceding claims, wherein A permanent magnetic device is provided around the through opening (2) on the second surface (1") of the panel (1), and wherein, at least in the area corresponding to the position of the permanent magnet, the closing unit is made of a material that can be attracted by the magnetic device, so that in the closed state of the plate, the magnetic device keeps the closing unit (3) in acoustically tight contact with the second surface (1") of the panel (1).

11. A panel according to any one of claims 1 to 9, wherein An electromagnetic device is provided around the through opening (2) on the second surface (1') of the panel (1), and, at least in an area corresponding to the position of the electromagnet, the closing unit is made of a material that can be attracted by the magnetic device, so that in the closed state of the plate, the magnetic device keeps the closing unit in sound-tight contact with the second surface of the panel.

12. A panel according to any one of the preceding claims, wherein A mechanical joining device is provided around the through opening (2) on the second surface (1") of the panel (1), and wherein, at least in an area corresponding to the position of the mechanical device, the closing unit is provided with a cooperating releasable mechanical joining device, so that in the closed state of the panel, the mechanical joining device enables the closing unit (3) to maintain sound-tight contact with the second surface (1") of the panel (1).

13. A panel according to any one of the preceding claims, wherein The panel (1) is provided with a sheet material on the first surface (1'), the sheet material being a facing sheet material, and the sheet material is provided with through openings corresponding to the through openings (2) in the panel (1).

14. A panel according to any one of the preceding claims, wherein The panel comprises an operating device configured to move the closing unit (3) between the open state and the closed state of the panel.

15. A panel according to any one of the preceding claims, wherein The panel (1) and the closing unit (3, 14, 30) both have an arched form, so that the sound impacting the front surface of the panel (or impacting the facing sheet attached to the front surface of the panel) becomes diffused; especially in the reflective (i.e. closed) state of the panel, the sound impacting the front surface of the panel (or impacting the facing sheet attached to the front surface of the panel) becomes diffused.

16. A device for changing the reverberation time (RT) of a room, such as a concert hall, wherein The device (D) comprises: - A panel according to any one of the preceding claims 1 to 13; a sound absorbing device, for example a piece of sound absorbing material (8), arranged so that the closing unit (3) is able to control the propagation of sound energy from the surroundings (S1) of the device towards the sound absorbing device; - attachment means (7) configured to attach the panel to a border (9) of the room so that a space (S3) is formed between the panel and the border (9), the sound absorbing device (8) being arranged in the space (S3); and - an operating device (23, 24, 39) configured to open or close the closing unit (3), - a surrounding device (51) which, in the closed state of the device, prevents acoustic energy from reaching the absorption device (8).

17. A covering system for a border portion (9) of a room, wherein The system comprises: - one or more sound absorbing devices according to claim 15; - Actuator means (25, 26), for example an electric motor, configured to drive operating means (23, 24) of the device between the open state and the closed state of the panel or between the closed state and the open state of the panel.

18. The system according to claim 17, wherein: The actuator (25, 26) is configured to maintain the closing unit (3) of the panel (P) in one or more states between a fully closed state and a maximum open state of the closing unit (3).

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