Planar element for the active compensation of noise in an interior room and anti-noise module therefor

Abstract

A planar element is provided for the active compensation of noise from different directions in an interior room. The planar element is equipped with anti-noise modules, each having a microphone and an electronic circuit having a combination of filters for adjusting phase and amplitude and an electronically controllable amplifier and a loudspeaker for active noise cancellation. The planar element is equipped over the width thereof with a plurality of anti-noise modules on each of a plurality of different longitudinally extending lines and is to be placed, for example, in front of a window having bounding walls. The anti-noise modules can be inconspicuously integrated into the planar element and jointly form longitudinally extending chains of anti-noise modules. The loudspeakers emit a canceling sound with respect to the noise, which canceling sound first passes through the planar element and subsequently largely cancels the noise.

Claims

1. A planar element, designed as a curtain for a window, as a standing wall or partition wall, as a ceiling part, or as a wall part for active compensation of background noise in an interior space, the planar element comprising: a plurality of identical anti-noise modules which are connected to one another and each have at least one microphone, an associated electronic circuit having a combination of filters for adapting phase and amplitude and in each case one associated central electronically controllable amplifier or amplifier assigned to the anti-sound module and in each case one associated loudspeaker, wherein the planar element has over its width on a plurality of different lines in each case a plurality of anti-sound modules which can be controlled analogously, which measure from 14 mm to 75 mm in thickness, from 90 mm to 200 mm in length, and from 40 mm to 200 mm in width, having a weight of from 50 grams to 300 grams per anti-sound module, so that they are integrated into the planar element and each together form each a chain of anti-sound modules extending along these lines, which are arranged in succession via electrical supply wires connecting them together in the form of two electrical wires each extending along this line, the chain being connected in parallel with its supply wires and being supplied with a low-voltage power by two electrical supply wires or supply rails which run transversely to the wires of the chains.

2. The planar element according to claim 1, designed as a curtain for a window, wherein the curtain comprises over its width, on several different falling lines, in each case a plurality of analogue controllable anti-sound modules which are integrated into the curtain and together in each case form a falling hanging chain of anti-sound modules, the electrical supply wires which connect them together are arranged suspended from one another in the form of in each case only two electrical wires running along the falling line, the chain being arranged with its supply wires connected in parallel by two electrical supply wires or supply rails under a low-voltage power, and which run transversely to the falling lines of the falling chains.

3. The planar element according to claim 1, designed as a standing wall or a partition wall, wherein a plurality of parallel lines, each having a plurality of analogue controllable anti-noise modules, are integrated into the standing or partition wall distributed over its width or height, so that they are integrated into the standing or partition wall and together each form a chain of anti-noise modules, which are arranged connected to one another via electrical supply wires connecting them together in the form of in each case only two electrical wires extending along the line of the chain, the chain being connected with its supply wires in parallel to two electrical supply wires or supply rails under a low-voltage power and which run transversely to the lines of the chains.

4. The planar element according to claim 1, designed as a ceiling element, wherein a plurality of parallel lines, each having a plurality of analogue controllable anti-noise modules, are integrated into the ceiling element distributed over its width or length or height, so that they are integrated into the ceiling element and each together form a chain of anti-noise modules, which are arranged connected to one another via electrical supply wires connecting them together in the form of in each case only two electrical wires extending along the line of the chain, the chain being connected with its supply wires in parallel to two electrical supply wires or supply rails under a low-voltage power which run transversely to the lines of the chains.

5. The planar element according to claim 1, wherein the amplifiers of the anti-sound modules have an output of up to 4 W and the loudspeakers have a load capacity of 4 W with an impedance of 8 , external dimensions of 100 mm50 mm and a maximum installation depth of 20 mm.

6. The planar element according to claim 1, wherein the amplifiers of the anti-sound modules have an output of up to 4 W and the loudspeakers have a load capacity of 4 W with an impedance of 8 , external dimensions of 100 mm50 mm and a maximum installation depth of 20 mm.

7. The planar element according to claim 1, wherein the amplifiers of the anti-sound modules have an output of up to 4 W and the loudspeakers have a load capacity of 4 W with an impedance of 8 , external dimensions of 100 mm50 mm and a maximum installation depth of 20 mm.

8. The planar element designed as a curtain for a window or as a standing or partition wall according to claim 1, wherein the microphones of each anti-sound module on the curtain or the standing or partition wall are aligned with their sensitive side towards one side of the curtain, so that the curtain or partition can be suspended or erected with these sensitive sides of the microphones directed towards one side, while the loudspeakers are then directed with the sound emitted by them towards the other side of the curtain away from it, for sounding an interior space.

9. The planar element designed as a curtain for a window or as a standing or partition wall according to claim 1, wherein the microphones of each anti-sound module on the curtain or the standing or partition wall are aligned with their sensitive side towards one side of the curtain, so that the curtain or partition can be suspended or erected with these sensitive sides of the microphones directed towards one side, while the loudspeakers are then directed with the sound emitted by them towards the other side of the curtain away from it, for sounding an interior space.

10. The planar element according to claim 1, designed as a curtain for a window, as a standing or partition wall, or as a ceiling part, wherein the anti-sound modules each have an electronic circuit which is designed wholly or partly as an integrated circuit according to a block diagram, which includes a unidirectional audio microphone, a preamplifier in each case, which is connected to an output stage via a filter/adjustment circuit and a volume control in each case, for generating and outputting electrical signals of the loudspeaker which are phase-shifted by 180 in comparison with the electrical signals generated by the microphone.

11. The planar element according to claim 1, designed as a curtain for a window, as a standing or partition wall or ceiling part, characterized in that the anti-sound modules have an electronic circuit which is designed wholly or partly as an integrated circuit and includes a low-pass filter with an upper cut-off frequency of 2 kHz, and further filters which compensate for the phase and amplitude characteristic of the amplification circuit and of the loudspeaker or loudspeakers.

12. The planar element according to claim 1, wherein the individual anti-sound modules have a circuit board and plastic elements which comprise the loudspeaker, the electronic circuit and at least two microphones which are spaced apart from one another and from the loudspeaker and being possible for the circuit to compensate for the phase shift of the signals of the microphones at different directions of the incoming sound, and after which these compensated signals can be delivered to the loudspeaker with 180 rotated phase.

13. The planar element according to claim 1, wherein the individual anti-sound modules have a circuit board and plastic elements which comprise the loudspeaker, the electronic circuit and at least two microphones which are spaced apart from one another and from the loudspeaker and being possible for the circuit to compensate for the phase shift of the signals of the microphones at different directions of the incoming sound, and after which these compensated signals can be delivered to the loudspeaker with 180 rotated phase.

14. An anti-noise module for installation in the planar element according to claim 1 for active compensation of background noise in an interior space by noise compensation, wherein this anti-noise module has stabilizing, protective plastic elements which also optimize the anti-noise, and at least one microphone aligned on one side of the circuit board and at least one loudspeaker aligned in the opposite direction are fitted, and at least one preamplifier connected to an output stage connected to the loudspeaker via a filter/adjustment circuit and a volume control, and connected for parallel connection to two electrical conductors, and in that this anti-sound module is up to 50 mm thick, up to 150 mm long and up to 100 mm wide and has a maximum weight of 200 grams.

15. An anti-noise module for installation in the planar element according to claim 1 for active compensation of background noise in an interior space by noise compensation, wherein the electrical circuit of the anti-noise module is a completely or partially integrated circuit, equipped with SMD components including a unidirectional audio microphone, and in that the loudspeaker is positioned with its loudspeaker diaphragm in the recess of a plate glued onto the front side of the circuit board and an elastomer insert with plug-in pins is plugged and glued onto the plate, while a felt insert is placed on the rear side of the loudspeaker and over its electrical part, and then a cover with a rib-reinforced rear wall is glued over the rear side of the loudspeaker onto the circuit board, which cover is intended to act as a resonance body for the inside loudspeaker, and in that the anti-noise module, together with the circuit board, plate and cover, is up to 50 mm thick overall and up to 150 mm long and up to 100 mm wide, having a maximum weight of 200 grams, having a flat loudspeaker with 4 W rated power, 8 Ohms rated impedance, and 120 to 20,000 Hz frequency range.

Description

(1) Details of the disclosure can be found in the following description of execution examples, drawings and patent claims. In the following, several examples of the disclosure are shown and described on the basis of these drawings. The drawings show:

(2) FIG. 1 shows an overview drawing of a typical anti-sound module for equipping a planar element according to the disclosure;

(3) FIG. 2 a block diagram of the electrical components provided in an anti-noise module of the planar element;

(4) FIG. 3 an example of an anti-noise module for the planar element with several microphones and/or loudspeakers;

(5) FIG. 4 a typical arrangement of several anti-sound modules in a planar element designed as a curtain on a window;

(6) FIG. 5 a schematic representation of the mode of action of the anti-sound modules of a curtain in the case of noise incident from perpendicular to the curtain, shown in a view from above;

(7) FIG. 6 a schematic representation of the mode of action of the anti-noise modules of a curtain in the case of noise incident from different directions, shown in a view from above;

(8) FIG. 7 an example of a planar element used as a curtain for an open window;

(9) FIG. 8 an example of a planar element as a slat curtain;

(10) FIG. 9 a cover, looked into its inside;

(11) FIG. 10 the lid seen from the inside in perspective;

(12) FIG. 11 the lid seen on its rear side;

(13) FIG. 12 a felt insert;

(14) FIG. 13 an elastomer insert seen on its rear side;

(15) FIG. 14 an elastomer insert seen on its front side;

(16) FIG. 15 a loudspeaker shown in perspective view;

(17) FIG. 16 looking back at the loudspeaker;

(18) FIG. 17 the loudspeaker seen on its front side;

(19) FIG. 18 a plate shown in perspective view;

(20) FIG. 19 a top view of this plate;

(21) FIG. 20 the plate seen from behind;

(22) FIG. 21 the assembled module shown in a perspective view;

(23) FIG. 22 the assembled module in a plan view of the front from which the anti-sound is radiated.

(24) FIG. 1 schematically shows the external design of an anti-sound module 12 for installation in a planar element according to the disclosure, whether this planar element is designed as a curtain, as a standing wall, as a partition wall, as a ceiling part that can be installed in a room or as a wall part. The first version of the anti-sound module 12 comprises a circuit board as the core, which also serves as a connecting element for the individual components to generate the anti-sound, in particular for the loudspeaker. 2. Plastic elements, for example a cover 26 and a plate 29 can be produced cheaply from ABS, i.e. from acrylonitrile-butadiene-styrene copolymers. These are thermoplastic terpolymers which are, however, relatively expensive to develop. Thanks to their optimized design, these plastic elements effectively stabilize the interior circuit board and, for example, give a curtain designed as a lamella curtain the right shape. In addition, a size-optimized plastic element (e.g. a cover 26) serves as a resonance body for the loudspeaker. The plastic used was successfully subjected to a UV stress test. The anti-sound module has suspension elements 3 to which connecting elements can be attached for suspension and, if necessary, connection to other anti-sound modules. These connecting elements can also be used for power supply and/or electrical control, in particular for volume control. The loudspeaker can be fixed by means of an elastomer that can be produced cheaply and is resistant to wear. Thanks to a special design, this elastomer fixes the loudspeaker with minimal transmission of vibrations. UV stress tests proved the resistance and durability of this elastomer. A polyester felt of optimized thickness and density, in which the loudspeaker 2 is embedded, dampens the vibrations of the loudspeaker 2 so that the vibrations are not transmitted to the circuit board and the plastic elements.

(25) At least one microphone 4 is arranged on the rear side facing away from loudspeaker 2, facing the source of the noise. Several loudspeakers 2 and/or microphones 4 can also be arranged in an anti-noise module 12. The depth of the anti-noise module 12 is primarily determined by the dimensions of the loudspeaker or loudspeakers 2if several are used. Exemplary dimensions of an anti-noise module 12 with a loudspeaker 2 are 150100 mm, with a depth of 30-50 mm or less. As such loudspeakers 2 are suitable cheap, such ones that are small and flat, with good performance, especially at lower frequencies, and with for example a nominal power handling of 4 W and a nominal impedance of 8 Ohms, which however have relatively large deviations of phase and amplitude over the frequency curve. These deviations were compensated by filters in a complex and innovative way in the course of the development. With the exception of four soldering processes for the power supply of the individual loudspeakers 2, the anti-sound module 12 can either be assembled loosely or its components can be glued together with inelastic superglue. All components are optimally matched to each other in order to achieve the necessary effectiveness. The individual Anti Noise Components ANC or Anti Noise Units 12 can be connected to each other by current-conducting, relatively stable and, above all, load-bearing copper strips. This is done exclusively by punching processes to adapt the copper strips, for example with two to four per board. The individual anti-noise modules are thus connected with thin copper strips, the ends of which can be firmly connected to the anti-noise modules by punching, and then these copper strips act on the one hand as fastening strips and on the other hand simultaneously as electrical supply wires.

(26) In a first version of the anti-noise module 12 for the planar element, a volume control via remote control by radio or cable is provided. In another version of the anti-sound module 12, the volume, i.e. practically the amplification of the microphone signal, is fixed during production. A circuit board 1 contains an electrical circuit, which is described below.

(27) FIG. 2 shows the block diagram of this electrical circuit for the anti-noise modules, which can be integrated into a planar element. This circuit is equipped with low-cost surface-mounted devices, i.e. SMD components, including a microphone. Microphone 4, for example a unidirectional audio microphone such as the AUM-5047L-3-LW100-R from PUI Audio, 3541 Stop Eight Rd. in Dayton, Ohio 45414, USA, feeds a preamplifier 6 which is connected to an output stage 9 via a filter/adjustment circuit 7 and a volume control 8. The latter delivers the phase-shifted output signal, adjusted to the noise level, to loudspeaker 2, which was already shown in FIG. 1. The electrical circuit cancompletely or partiallybe an integrated circuit (IC) on a circuit board 1 or can be made up of commercially available electronic components. Only (or with a few exceptions) low-cost SMD components including microphones are being used. In one variant, the anti-noise module 12 can consist solely of a suitably shaped circuit board 1, which is equipped with the various SMD components, i.e. also serves as a holder for the loudspeaker 2 in order to save costs and weight. This version does not actually require a closed cabinet, but a cover 26 and a plate 29 for accommodating the individual components or parts.

(28) As mentioned in the description of FIG. 1 above, the microphone 4 is arranged on the side of the anti-sound module 12 opposite the loudspeaker 2. The use of a directional microphone or a microphone with a relatively narrow polar pattern is recommended in order to exclude or minimize acoustic feedback with the loudspeaker 2 accommodated in the same anti-sonic module 12. Despite the phase rotation of the acoustic output signal, i.e. the anti-sound, this possible feedback must be avoided because of the relatively wide frequency band used, usually up to 2000 Hz.

(29) The filter/adjustment circuit 7 preferably contains a low-pass filter with an upper cut-off frequency of e.g. fg=2 kHz, as well as further filters which compensate the phase and amplitude characteristics of the amplification circuit and in particular the phase and amplitude characteristics of the loudspeaker(s) 2. This generates the required phase rotation ofideally180 degrees. Tests have shown that with a phase rotation of around 180 degrees at 703.2 Hz, a maximum noise reduction of up to 20 dB can be achieved.

(30) The volume control 8 regulates the volume preferably non-linearly with the help of the external power supply, i.e. by means of the power supply circuit 10. A minimum current consumption is aimed at, since a multitude of anti-noise modules 12, for example 50 anti-noise modules 12 in a planar element, may have to be supplied. As mentioned in connection with FIG. 1, however, a manual or preset volume control can also be used.

(31) In the example, power stage 9 is designed for approx. 4 W. An 8 ohm loudspeaker 2 is operated with this power as an example, e.g. type SC 4.9 FL from VISATON GmbH & Co. KG, Ohligser Str. 29-31, D-42781 Haan, Germany. This 4 W loudspeaker is characterized by a small size with external dimensions of 90 mm40 mm and, above all, a basic depth of only 14 mm, with which a rather flat, lightweight anti-sound module 12 can be realized. Of course, similar loudspeakers can be used, possibly even more compact ones. In total, a complete single anti-sound module 12 of this type weighs less than 200 grams, i.e. only 150 grams. This low weight makes it possible to integrate the anti-noise modules 12 in a large number into a textile curtain, a lamella curtain or other planar elements.

(32) The anti-noise modules 12 of the planar element are supplied with low-voltage power via two electrical supply wires with a single volume control for the entire installation, either via an external connection not shown here, or a battery or accumulator is provided in the anti-noise module 12, and the low-voltage power is drawn from a battery or accumulator. An external connection can also be provided if a wired volume control is being used.

(33) FIG. 3 shows another version of a single anti-noise module 12 for a curtain as a planar element. In this design, two microphones 4 and 4 are arranged in the anti-noise module 12 in addition to loudspeaker 2 and circuit board 1, with the microphones facing loudspeaker 2 as shown in FIG. 1. This allows the electrical circuit on circuit board 1 to transmit a more balanced signal to loudspeaker 2 to produce the anti-sound. The distance between the microphone and the loudspeaker results in a phase shift between the location of the microphone and the loudspeaker when the sound falls in obliquely from above or below. This phase shift can be compensated for by suitable connection of two microphones 4, 4 with the same distance to loudspeaker 2. Alternatively, combinations of four microphones and one loudspeaker are possible, or of two microphones with two loudspeakers. Other combinations are also possible.

(34) FIG. 4 shows a typical arrangement of the anti-noise modules 12 in a curtain as a planar element 24, suitable for equipping a double-wing, fully open window 13 or a corresponding opening. In the interior, five rows of five vertically connected anti-sonic modules 12 are integrated in the curtain and arranged essentially centrally within window 13. The loudspeakers 2 generating the anti-sound are shown schematically. The anti-noise modules 12 are suspended or connected to each other as simultaneous supply lines on wires 11, which are barely noticeable. Depending on the design of the anti-noise modules 12as described abovethese wires 11 also serve for switching on and off, for control/regulation, in particular volume control and/or for power supply of the anti-noise modules 12. Number and arrangement of the anti-noise modules 12, shown here in a 55 grid, are of course free and are selected in such a way that the desired degree of noise cancellation or noise reduction is achieved over the desired frequency range. Thus it is quite possible to arrange a corresponding number of anti-noise modules 12 only at the edge of a window sash, as shown in FIG. 7 and according to the corresponding description, for example in order to save costs and not unnecessarily obstruct the view through the window, even if the desired noise cancellation or noise reduction is achieved in this way.

(35) FIGS. 5 and 6 schematically show the mode of action for different directions and properties (e.g. static versus dynamic) of the incident noise. The invented planar element 24 as sound insulation arrangement, here in the form of a curtain with self-sufficient anti-noise modules 12, makes it possible to simulate the dynamics of the noise to be corrected, for example the noise of a passing car, and to achieve suitable compensation.

(36) FIG. 5 shows a vertical incident sound 14 with direction 17 of incidence, which penetrates through a window or an opening. The boundary walls 13 of the window are shown, and at their edges the incident sound is partially diffracted, according to which it is diffracted noise 15. The anti-noise modules 12 of the planar element 24 generate an even anti-noise 16, which is superimposed with a 180 degree phase shift on the incident noise 15 and thus achieves the desired noise reduction.

(37) FIG. 6 shows an incident sound 14 from the outside with an incident direction 17, which penetrates at oblique angle through the window or an opening. The opening is again represented by the boundary walls 13. In the interior the noise occurs with diffracted noise waves 15. The anti-noise modules 12 generate an anti-noise 16 adapted to the spatial dynamics, which is superimposed with 180 degree phase shift on the noise waves 15 and thus achieves the desired noise reduction. Due to the distribution of the anti-noise modules 12 in the planar element 24, the phase difference of the incident noise wavesfor example between the left and right edge of the window or the openingis taken into account when generating the anti-noise.

(38) As mentioned above, a single anti-noise module 12 is approximately 150 mm100 mm in size, with a depth or thickness of 30-75 mm or less. The horizontal and/or vertical arrangement should include an anti-noise module 12 approximately every 100 mm to 200 mm. This depends essentially on the overall arrangement of the anti-sound modules 12 in the planar element 24which also depends on the frequency range to be compensatedfor example in a curtain. In a lamella curtain, as shown and described below, such an arrangement is provided, for example.

(39) FIG. 7 shows an example of an application for a tilted, i.e. not fully opened, window 18, for a door or a passageway between two rooms, which, for example, is provided with a sound-insulating curtain as a planar element 24. Since the background noise enters the interior to be protected primarily through openings, thanks to the modular structure these can be covered specifically with the ingenious planar element 24 in the form of a curtain and thus the noise can be reduced effectively and cost-effectively, i.e. with fewer anti-noise modules 12. In the case of window 18 shown in FIG. 7, which is only tilted and therefore not fully opened, only those areas which are directly in front of the openings need to be fitted with anti-noise modules 12. The upside-down U formation of the anti-noise modules 12 meets this requirement. Of course, the anti-noise arrangement must leave sufficient space for people to pass through a door or passageway.

(40) It is advantageous to connect the anti-noise modules 12 inside the planar element 24 or curtain by means of a suspension which ensures mechanical stability as well as power supply and, if necessary, volume control. In most cases it will be advantageous to make this suspension flexible overall, for example by using cables or wires as connecting elements. For design reasons, the anti-noise modules 12 can be made up as dummies or combined with a specific type of curtain or integrated into a special curtain, for example into a lamella curtain.

(41) FIG. 8 shows an example of such a lamella curtain. In a fabric or fabric web 25, a number of anti-sound modules 20 corresponding to the length of the web 25 is permanently arranged, for example sewn or glued into elongated pockets, possibly supplemented by an additional shaping plastic or light metal frame. This path or web 25 with the anti-sound modules 20 forms a lamella 19, as they are similarly used in vertical lamella curtains. In the example shown, the anti-noise modules 20 have a lenticular or oval cross-section. The anti-noise modules 20 are electrically connected in parallel to each other via wire 21 for power supply and/or volume control. The upper suspension 22 is designed as a supply line next to the mechanical fastening so that the power supply and/or the control can be transmitted electrically. The curtain rail 23 is also designed in such a way that, in addition to the sliding and rotating slats, the power supply and/or control is also possible. Both are only indicated in FIG. 8, as is a second lamella 19, which can also be equipped with anti-noise modules. Of course, module slats can also be arranged alternately with slats without anti-noise modules, which together form the planar element, or any combination of module slats and slats without anti-noise modules can be formed, depending on the desired capacity of the noise compensation. Here again the simple installation of the inventive planar element or curtain as anti-noise arrangement is shown, which is also possible to install by non-specialists, whereby the desired noise compensation can be adjusted once during installation by simple trial and error and can be improved at any time easily and with little effort if the noise conditions change.

(42) Instead of a lamella curtain equipped with anti-noise modules, mobile partitions with anti-noise modules can also be realized as planar elements according to the disclosure and used in a similar way. This would be useful, for example, if there are noisy machines in an open-plan office whose background noise is to be compensated. Such planar elements designed as partitions have a similar structure to the previously shown curtain design examples and are therefore not explicitly shown. Mobile partition walls as planar elements, which contain the anti-noise modules hidden at an optimised distance from each other, make it possible in a flexible way to protect certain parts of the room against noise, to ensure privacy and/or to contain sound reflections.

(43) The same applies to a flat ceiling part or ceiling element or a flat wall part or wall element as a planar element with integrated anti-noise modules, with which, for example, background noise from a floor above the room in question or from an adjacent room can be compensated. Such single or several ceiling or wall elements are used for this purpose. The anti-noise modules can also be integrated into blinds or shutters, which then become planar elements with anti-noise function. Such implementations will not cause any difficulties for the expert.

(44) In the following figures not only a schematic representation of the individual components of such a planar element is shown, but an example of an actual conversion of the planar element with its anti-sound modules and the components for it and how these components look or can look like. It is clear that the structure of the planar element as well as of the individual anti-sound modules can be varied, and in particular also their dimensioning. However, the structure of the planar element presented here proves to be functional and suitable for practical use. First, FIG. 9 shows a cover 26 for a single anti-sound module, seen from the inside. One can see here a grid-like rib structure 5 to reinforce the rear wall. This cover 26 is intended to cover the back of the loudspeaker. In FIG. 10 the cover 26 is shown in a perspective view of the inside of the rear wall, and in FIG. 11 it is shown with a view of the outside of the rear wall. It is an injection-moulded plastic part.

(45) Another mounting part is a felt insert 28 with recess 34 as shown in FIG. 12, which serves to damp the loudspeaker vibrations. Another component of the anti-noise module 12 is a soft elastomer insert 27 as shown in FIG. 13, where it can be seen on its back. The inner area 33 forms a recess, thus a free passage, and at the four corners arms 32 protrude over the edge and these are interspersed with pins 30 made of plastic or metal. FIG. 14 shows the smooth front of this elastomer insert 27.

(46) FIG. 15 shows the loudspeaker 2 in perspective as it is suitable for installation in this anti-sound module. It is a particularly light and flat loudspeaker 2, measuring for example 150 mm100 mm, with a depth of 30 mm to 75 mm or less, and with a rated power handling of 4 W and a rated impedance of 8 Ohms. FIG. 16 shows this loudspeaker 2 seen on its rear side. Here one can see the electrical part 38 of loudspeaker 2, and FIG. 17 shows its front side. The speaker diaphragm 37 is held and mounted by a soft, circumferential rubber lip 35. Furthermore, FIG. 18 shows a grid-like plate 29 in perspective view, with a central recess 36 and FIG. 19 in plan view, and FIG. 20 shows it seen from the other side.

(47) All these parts mentioned and shown above are assembled into a single anti-sound module 12, as shown in FIG. 21 and FIG. 22. First the felt insert 13 is put over the speaker 2 from behind, so that the electrical part 38 of the speaker 2 comes to rest in the recess 34 at the felt insert 28. This felt insert 28 serves to dampen the vibrations of loudspeaker 2 on its rear side. Then the plate 29 with recess 36 is laid over the front side of the loudspeaker and then the elastomer insert 27 is attached to its arms 32 of the plate 29 by means of its pins 30. The loudspeaker 2 with plate 29 is placed with its front side facing upwards, from which the sound is radiated, i.e. with the loudspeaker diaphragm 37 visible in FIGS. 21 and 22, on the recess provided for it on circuit board 1, so that its loudspeaker diaphragm 37 lies above the congruent recess on circuit board 1. The loudspeaker 2 is then covered from behind with the cover 26, whereby this cover 26 (as well as the plate 29 on the opposite side of the circuit board 1) is glued to the circuit board 1. The various switching elements are then located outside the cover on the circuit board 1. An entire chain can be formed from such anti-sound modules 12 by connecting them to the fastening elements 31. A number of such chains arranged side by side finally form a planar element after the disclosure and this can, for example, be integrated into a curtain made of fabric or other materials or the planar element forms a curtain.

(48) Since the operation of such a single anti-noise module or an entire anti-noise arrangement consisting of several anti-noise modules 12 in the form of a planar element can be limited to the time during which persons are present in the room to be protected from the noise, switched operation definitely makes sense and is useful. The anti-noise arrangement can be switched on and off by one or more motion detectors in an anti-noise module or externally. A time switch is also possible, although this is not explicitly shown in the figures. Such motion detectors or time switches are usually used for automatic light activation and light deactivation. The expert does not have much trouble to implement the concept of a planar element with anti-sonic modules other than explicitly described here.

(49) The present disclosure therefore shows a relatively simple solution which can be installed indoors with comparatively little effort, especially retrospectively, and which can be adapted to the specific noise situation.

INDEX OF NUMBERS

(50) 1 Circuit board 2 Loudspeakers 3 Mounting element/supply line 4 Microphone 5 Grid-like rib structure 6 Preamplifier 7 Filter/adjustment circuit 8 Volume control 9 Output stage 10 Power supply circuit 11 Wire, supply line 12 Anti-noise module 13 Boundary wall window 14, 14 Noise in FIG. 5 or 6 15, 15 Diffracted noise in FIG. 5 or 6 16, 16 Anti-noise in FIGS. 5 and 6, respectively 17, 17 Direction of incidence of background noise in FIGS. 5 and 6 respectively 18 Open window 19 Blade 20 Anti-sonic module in cable 21 21 Cable with anti-noise modules 20 22 Suspension, supply line 23 Curtain rail 24 Planar element in FIGS. 5, 6 and 7 25 Planar element in FIG. 8 26 Cover 27 Elastomer insert 28 Felt insert 29 Plate 30 Pins 31 Mounting element for connecting and supplying individual anti-noise modules 32 Arms on elastomer insert 27 33 Recess on elastomer insert 34 Recess on felt insert 35 Rubber lip as loudspeaker membrane holder 36 Recess on the plate 37 Loudspeaker membrane 38 Electrical part of loudspeaker 2