Glass panel for emitting acoustic waves

Abstract

The present invention relates to a glazed assembly for a vehicle, which is suitable for emitting acoustic waves, the glazed assembly comprising a glass panel, the glass panel comprising a first face suitable for being arranged on the inside of the vehicle and a second face suitable for being arranged on the outside of the vehicle, the glazed assembly comprising at least one first exciter and at least one second exciter.

Description

Description Title of the invention: Glazing for the emission of acoustic waves Field of invention [1] The present invention relates to glazing for the emission of acoustic waves, particularly in the low and medium frequencies. It relates more generally to the interior sound system of a vehicle. State of the art [2] A surface exciter makes it possible to generate an acoustic wave from a membrane formed by a wall, for example a glass wall. The generation of the acoustic wave is driven by the vibrations of the wall on which the exciter is fixedly mounted, via a rigid connection. An assembly comprising the exciter and the wall thus makes it possible to emit and / or receive an acoustic wave. In a vehicle, use of this system allows in particular a saving of space and mass with regard to the use of a set of loudspeakers installed in the passenger compartment of the vehicle. In addition, the use of loudspeakers installed in the passenger compartment makes it difficult to generate a sound environment specifically in the volumes of the passenger compartment surrounded by the vehicle's windows. [3] It is known to mount an exciter fixedly on a vehicle window. Document WO2023 / 083883 describes, for example, an exciter comprising a fixed part and a mobile part, the fixed part being mounted fixedly on the vehicle window. [4] However, such a system has a lower limit frequency for emitting an acoustic wave that is too high. In particular, such a system does not have as high an acoustic performance as a known system comprising loudspeakers adapted to low frequencies, also known as woofers (adapted to low and medium frequencies) or subwoofers (adapted to low frequencies). Statement of the invention [5] An aim of the invention is to propose a system making it possible to at least partially resolve the aforementioned drawbacks of the state of the art. [6] This aim is achieved, at least partially, within the framework of the present invention thanks to a glazed assembly for a vehicle adapted to emit acoustic waves, the glazed assembly comprising a glazing, the glazing comprising a first face adapted to be arranged inside the vehicle and a second face adapted to be arranged outside the vehicle, the glazed assembly comprising: - at least one first exciter comprising a first connecting part and a first mobile part, the first exciter being configured to cause a periodic movement between the first connecting part and the first mobile part by electrical control, the first connecting part being fixedly mounted on the first face, the first exciter being adapted so that the movement between the first connecting part and the first mobile part has a frequency equal to 100 Hz, and - at least one second exciter comprising a second connecting part and a second moving part, the second exciter being configured to cause a periodic movement between the second connecting part and the second moving part by electrical control, the second connecting part being fixedly mounted on the first face, the second exciter being adapted so that the movement between the second connecting part and the second moving part has a frequency equal to 1 kHz, characterized in that: - the first connecting part has a first mass M m , the sum of the first mass(es) M m being between 200 g and 10 kg, and - the glazing having a length L x , a width L y and a thickness h predetermined so that a first natural frequency fn of the glazing is less than 100 Hz, the first natural frequency fi 1 being defined by: where D is the bending stiffness of the glazing expressed in Nm, p is the average mass density of the glazing expressed in kg / m 3 and where: 0.017 and ^(nor) = 7772 - 1 0.017. ® « [7] The present invention is advantageously supplemented by the following characteristics, taken individually or in any of their technically possible combinations: [8] - the glazed assembly comprises a plurality of first exciters, the sum of the first masses M m being between 200 g and 10 kg, [9] - the first connecting part comprises a first magnet and the first movable part comprises a first electrically conductive coil,

[0010] - the assembly of the first magnet(s) has a mass M mi between 100 g and 10 kg,

[0011] - the second connecting part has a mass M c less than 20 g,

[0012] - the glazed assembly comprises a plurality of second exciters,

[0013] - the second connecting part comprises a second electrically conductive coil and the second moving part comprises a second magnet,

[0014] - each second coil has a mass M C 2 less than 20 g,

[0015] - the glazing comprises an opaque coating, the first exciter(s) and preferably the second exciter(s) being mounted fixedly on the first face opposite the opaque coating or on the opaque coating,

[0016] - the glazing is a laminated glazing comprising a layer based on poly(vinyl butyral), the layer based on poly(vinyl butyral) comprising a plasticizer, a mass content of the plasticizer in the layer being strictly greater than 28.5%,

[0017] Another aspect of the invention is a vehicle comprising a glazed assembly according to one embodiment of the invention, the glazed assembly forming a roof of the vehicle.

[0018] Advantageously, the vehicle comprises at least a first loudspeaker adapted to emit an acoustic wave having a frequency equal to 10 kHz.

[0019] Advantageously, the vehicle comprises at least one second loudspeaker adapted to emit an acoustic wave having a frequency equal to 100 Hz and at least one third loudspeaker adapted to emit an acoustic wave having a frequency equal to 1 kHz.

[0020] Advantageously, the glazing has natural frequencies, the vehicle comprising a control unit configured to transmit an electrical signal representative of an acoustic signal to the first exciter(s) and / or to the second exciter(s), the control unit comprising a module for transforming an acoustic signal configured to modify a first incoming electrical signal associated with a first acoustic signal into a second outgoing electrical signal associated with a second acoustic signal, so that the second acoustic signal has an amplitude at a natural frequency of the glazing smaller than the amplitude at the same natural frequency of the first acoustic signal.

[0021] Advantageously, the vehicle comprises a control unit configured to transmit a third electrical signal representative of a third acoustic signal to a second exciter, a fourth electrical signal representative of a fourth acoustic signal to another second exciter, concomitantly, the third acoustic signal being different from the fourth acoustic signal.

[0022] Advantageously, the vehicle comprises a control unit configured to emit an electrical signal representative of an acoustic wave to the first exciter(s) and / or to the second exciter(s), the control unit comprising a synchronization module configured to introduce a delay into the acoustic wave, the delay being predetermined from the location on the first face of the first exciter(s) or of the second exciter(s). second exciters to which the electrical signal is emitted. Description of the figures

[0023] Other characteristics, aims and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting, and which must be read in conjunction with the appended drawings in which:

[0024] [ Fig.1 ] - Figure 1 schematically illustrates a glazed assembly according to one embodiment of the invention,

[0025] [Fig.2] - Figure 2 schematically illustrates a section of a glazed assembly according to one embodiment of the invention,

[0026] [Fig.3] - Figure 3 schematically illustrates a section of a detail of a glazed assembly according to an embodiment of the invention and more particularly a section of a first exciter,

[0027] [Fig. ] - Figure 4 schematically illustrates a section of a detail of a glazed assembly according to an embodiment of the invention and more particularly a section of a second exciter,

[0028] [Fig.5] - Figure 5 schematically illustrates a top view of a vehicle according to one embodiment of the invention,

[0029] [Fig.6] - Figure 6 schematically illustrates a top view of a vehicle according to one embodiment of the invention,

[0030] [Fig.7] - Figure 7 illustrates a variation of an acoustic pressure level emitted by a set of loudspeakers on the one hand and by a glass assembly according to an embodiment of the invention on the other hand, with the frequency.

[0031] Throughout the figures, similar elements have identical references. Detailed description of the invention

[0032] General description of the glass unit 1

[0033] Referring to Figure 1 and Figure 2, one aspect of the invention is a glazed assembly 1 for a vehicle 2. The glazed assembly 1 is adapted to emit acoustic waves. The glazed assembly 1 comprises a glazing unit 3. The glazing unit 3 comprises a first face 4 adapted to be arranged inside the vehicle. The glazing unit 3 comprises a second face 5 adapted to be arranged outside the vehicle.

[0034] The glazed assembly 1 also comprises at least one first exciter 6 and at least one second exciter 7.

[0035] Referring to Figure 3, the first exciter 6 comprises a first connecting part 8 and a first movable part 9. The first exciter 6 is configured to cause a periodic movement between the first connecting part 8 and the first movable part 9 by electrical control. The first connecting part 8 of the first exciter 6 is fixedly mounted on the first face 4.

[0036] The first exciter 6 is adapted so that the movement between the first connecting part 8 and the first moving part 9 has a frequency equal to 100 Hz. Thus, the first exciter is adapted to vibrate in low frequencies.

[0037] Referring to Figure 4, the second exciter 7 comprises a second connecting part 15 and a second moving part 16. The second exciter 7 is configured to cause a periodic movement between the second connecting part 15 and the second moving part 16 by electrical control. The second connecting part 15 of the second exciter 7 is fixedly mounted on the first face 4.

[0038] The second exciter 7 is adapted so that the movement between the second connecting part 15 and the second moving part 16 has a frequency equal to 1 kHz. Thus, the second exciter 7 is adapted to vibrate in the medium frequencies.

[0039] The first connecting part 8 has a first mass M m The sum of the first mass(es) Mm is between 100 g and 10 kg, in particular between 250 g and 8 kg and preferably between 100 g and 7.5 kg.

[0040] A first natural frequency fn of glazing 3 is defined by: where D is the bending stiffness of glazing 3 expressed in Nm, p is the average mass density of glazing 3 expressed in kg / m 3 , L x is a length of the glazing 3, L y is a width of the glazing 3, and where:

[0043] Length L x , the width L y and the thickness h are predetermined so that a first natural frequency fn of the glazing is less than 100 Hz, in particular less than 50 Hz, and preferably less than 30 Hz.

[0044] Thus, the glazed assembly 1 can emit acoustic waves in the low frequencies, that is to say having a frequency between 20 Hz and 100 Hz, in particular between 20 Hz and 50 Hz and preferably between 20 Hz and 30 Hz.

[0045] Indeed, the inventors discovered that the frequency of the acoustic waves emitted by the glazed assembly 1 must be greater than two interdependent frequencies: a first minimum cut-off frequency f mmi dependent on the first exciter(s) 6 and a second minimum cut-off frequency f mm 2 dependent on the dimensions and composition of the glazing 3.

[0046] The first minimum cutoff frequency f mmi can be calculated by the following formula in the case of vehicle glazing: where Z m is the mechanical impedance of the glazing 3, defined by the following formula:

[0048] Z m = SD (5)

[0049] where Z = ph is the mass per unit area of ​​the glazing, expressed in kg / m 2 , p is the mass density of glazing 3, h is the thickness of glazing 3 and D is the bending stiffness of glazing 3, defined by:

[0051] where E is the Young's modulus of glazing 3 and v is the Poisson's ratio of glazing 3. Thus, with regard to formula (4) and for glazing 3, a sum M m of the first mass(es) between 100 g and 10 kg, in particular between 250 g and 8 kg and preferably between 100 g and 7.5 kg, results in f mmi is less than 100 Hz, in particular less than 50 Hz and preferably less than 30 Hz.

[0052] The second minimum frequency f mm 2 is the first natural frequency of the glazing 3. Generally speaking, a natural frequency f mn, m being the mode according to a length of the glazing and n being the mode according to a width of the glazing, can be defined by:

[0053]

[0054] Or

[0055]

[0056] And

[0057]

[0058] Thus, the first natural frequency fn can be calculated by formulas (7), (8) and (9), as defined in formulas (1), (2) and (3). The height h, the length L x and the width L y are thus chosen for 3 glazing predetermined composition so that the second minimum cutoff frequency f mm 2 is less than 100 Hz, in particular less than 50 Hz and preferably less than 30 Hz.

[0059] Plurality of first exciters 6 and / or second exciters 7

[0060] The glazed assembly 1 may comprise a plurality of first exciters 6. In this case, the sum Mm of the first masses is between 100 g and 10 kg, in particular between 250 g and 8 kg and preferably between 100 g and 7.5 kg. Thus, it is possible to distribute the mass of the first exciters on the first face 4, which makes it possible to reduce the risks of breakage of the glazing 3.

[0061] The glazed assembly 1 may comprise a plurality of second exciters 7. Thus, it is possible to generate directional sound bubbles around a user of the vehicle. Indeed, for medium frequencies, and unlike low frequencies, the acoustic waves emitted by the glazed element 1 may be directional. It is therefore possible to generate a plurality of sound bubbles when the glazed assembly 1 comprises a plurality of second exciters 7.

[0062] First exciter(s) 6

[0063] With reference to Figure 3, the first exciter 6 is adapted so that the movement between the first connecting part 8 and the first mobile part 9 has a frequency equal to 100 Hz. Preferably, the movement can have a frequency between 20 Hz and 100 Hz.

[0064] The first connecting part 8 of the first exciter 6 comprises a first magnet 17. The first moving part 9 of the first exciter 6 comprises a first electrically conductive coil 18.

[0065] The assembly of the first magnet(s) 17 has a mass M mi between 100 g and 10 kg, in particular between 250 g and 8 kg and preferably between 100 g and 7.5 kg.

[0066] A preferred configuration of the arrangement of the first exciter 6 is a so-called "shaker" configuration. The first connecting part 8 is fixedly mounted to the first face 4 and surrounds the first movable part 9. The first connecting part 8 comprises a housing, the housing surrounding the first movable part 9. The first magnet 17 is fixedly mounted on the housing. The first movable part 9 is mechanically connected to the first face 4 by a spring-type mechanical connection. The first movable part 9 comprises the first coil 18 which is mounted inside the housing and which can be suspended relative to the first face 4 by electrical control of the electric current generated in the first coil 18.

[0067] Second exciter(s) 7

[0068] With reference to Figure 4, the second exciter 7 is adapted so that the movement between the second connecting part 8 and the second mobile part 9 has a frequency equal to 1 kHz.

[0069] The glazed assembly 1 may have a maximum cut-off frequency fmaxi, partially controlled by the second exciter(s) 7. The maximum cut-off frequency f maxi can be defined by the following formula:

[0070] f max =^ (10)

[0071] where Z m is the mechanical impedance of the glazing 3 defined previously and where M c is the mass of the second connecting part 15 of the second exciter 7. The glazed assembly 1 is adapted to emit an acoustic wave in a frequency range between, on the one hand, the minimum frequency of the group formed by the first minimum cut-off frequency f mmi and the second minimum cutoff frequency f mm2, and on the other hand by the maximum cut-off frequency f maxi •

[0072] The second connecting part 15 may have a mass M c less than 20 g, in particular less than 15 g and preferably less than 10 g. Thus, it is possible to increase the maximum cut-off frequency f maxi and thus extend the frequency range of the glazed element 1.

[0073] With reference to Figure 4, in a preferred configuration, the second connecting part 15 comprises a second electrically conductive coil 20. The second movable part 16 comprises a second magnet 19. Preferably, the second coil 20 has a mass M C2 less than 20 g. The second connecting part 15 can be fixedly mounted to the first face 4. The second movable part 16 can be mounted on the second connecting part 15 and connected by a spring-type mechanical connection to the second connecting part 15. The second coil 20 can be fixedly mounted to the second connecting part 15. The second movable part 16 can form a housing covering the second coil 20. A second magnet 19 can be fixedly mounted in the housing.

[0074] Arrangement of the first exciter(s) 6 and the second exciter(s) 7

[0075] With reference to Figure 5 and Figure 6, the glazing 3 may comprise an opaque coating 10. The opaque coating 10 may be formed by a layer of opaque enamel. The opaque coating may be inserted between two sheets of glass forming the glazing 3 or cover an outer face of a sheet of glass forming the glazing 3.

[0076] With reference to figure 6, the first exciter(s) 6 and preferably the second exciter(s) 7 can be mounted fixedly on the first face 4 opposite the opaque covering 10 or on the opaque covering 10. Thus, the exciters do not obstruct the visibility of a user of the vehicle through the glazing 3.

[0077] Glazing 3

[0078] The glazing 3 may be a laminated glazing comprising a layer of PVB (polyvinyl butyral). In particular, the PVB layer may be formed by three superimposed layers. Two so-called "skin" layers of the three layers may be formed from standard PVB, i.e. comprising a plasticizer mass content of between 17% and 28.5%. A so-called "core" layer may be surrounded by the two skin layers and comprise a plasticizer mass content strictly greater than 28.5%. Thus, it is possible to equalize the acoustic response of the glazing 3. The inventors have in fact discovered that an amplitude peak of the acoustic waves observed for natural frequencies of the glazing 3 is smoothed when using an acoustic PVB layer compared to a glazing not comprising acoustic PVB.

[0079] Vehicle 2

[0080] With reference to Figure 5 and Figure 6, the glazing 3 can be adapted to form a roof 11 of the vehicle 2. Another aspect of the invention is a vehicle 2 comprising the glazed assembly 1 forming the roof 11 of the vehicle 2. Thus, it is possible to arrange the second exciters 7 above the transport positions of the passenger(s) so as to create a predetermined sound bubble for a predetermined passenger.

[0081] The vehicle 2 may comprise at least one first loudspeaker 12 adapted to emit an acoustic wave having a frequency equal to 10 kHz. Thus, it is possible to cover the entire auditory spectrum when emitting acoustic waves by a system comprising the glazed assembly 1. The vehicle 2 may comprise at least one second loudspeaker 13 adapted to emit an acoustic wave having a frequency equal to 100 Hz. The vehicle 2 may comprise at least one third loudspeaker 21 adapted to emit an acoustic wave having a frequency equal to 1 kHz. Thus, it is possible to increase the spatialization of the sources emitting acoustic waves.

[0082] The glazing 3 can be fixedly mounted to a vehicle structure by means of glue. Thus, it is possible to control the acoustic amplitude emitted by the glazed element 1 of a glazing 3 with regard to the acoustic amplitude emitted by a glazing 3 mounted without glue.

[0083] With reference to Figure 5 and Figure 6, the vehicle 2 may comprise a control unit 14.

[0084] The control unit 14 may be configured to transmit an electrical signal representative of an acoustic signal to the first exciter(s) (6) and / or to the second exciter(s) 7. The control unit 14 may comprise a module for transforming an acoustic signal configured to modify a first incoming electrical signal associated with a first acoustic signal into a second outgoing electrical signal associated with a second acoustic signal, such that the second acoustic signal has an amplitude at a natural frequency of the glazing 3 that is smaller than the amplitude at the same natural frequency of the first acoustic signal. Thus, it is possible to smooth the amplitude variations in frequency of the acoustic waves emitted by the glazed assembly 1. Indeed, without the smoothing that can be implemented by the transformation module, the amplitude of the emitted acoustic wave is higher for frequencies corresponding to the natural frequencies of the glazing 3.

[0085] The control unit 14 can be configured to transmit a third electrical signal representative of a third acoustic signal to a second exciter 7, and a fourth electrical signal representative of a fourth acoustic signal to another second exciter 7, concomitantly, the third acoustic signal being different from the fourth acoustic signal. Thus, it is possible to implement a spatialization of the sound in the passenger compartment of the vehicle. Such a spatialization cannot be implemented only with the first exciters because it is not possible to spatialize the sound with low frequencies.

[0086] The control unit 14 may be configured to transmit an electrical signal representative of an acoustic wave to the first exciter(s) 6 and / or to the second exciter(s) 7. The control unit 14 may comprise a synchronization module configured to introduce a delay into the acoustic wave. The delay may be predetermined from the location on the first face 4 of the first exciter(s) 6 or of the second exciter(s) 7 to which the electrical signal is emitted. Thus, it is possible to synchronize the acoustic sound waves arriving at a point in the passenger compartment of the vehicle 2 by compensating for the delays caused by the transmission of the sound waves from different points of the vehicle 2, for example a first exciter 6 and a second exciter 7.

[0087] The glazing 3 of the glazed assembly 1, when the glazed assembly 1 forms the roof of the vehicle 2, may comprise liquid crystals contained in an electrically activated film. In addition, the glazing 3 may be configured to allow localized activation of lighting in the glazing 3.

[0088] Examples

[0089] Glazing 3 can have a density p equal to 2500 kg / m 3 . The thickness h of the glazing 3 can be equal to 4.96 mm. The Young's modulus E of the glazing can be equal to 72 GPa. The Poisson's ratio of the glazing can be equal to 0.3. The mechanical impedance Z m of the glazing is then 572 Ns / m. The sum M m of the first mass(es) is equal to 4.5 kg. Thus, the frequency f mmi is equal to 20 Hz. The mass M c is equal to 100 g. Thus, the frequency f maxi is equal to 20 kHz. The length L x of glazing 3 is equal to 1.2 m and the width L yof glazing 3 is equal to 1.4 m. The first natural frequency fi 1 of glazing 3 is thus equal to 24 Hz. Glazing 3 comprises a layer of acoustic PVB and two sheets of glass each with a thickness of 2.1 mm.

[0090] Figure 7 illustrates a variation of the sound pressure level with frequency for loudspeakers and for a glass assembly 1. In particular, curve (a) illustrates a variation of the sound pressure level with frequency for acoustic waves emitted by an assembly formed by four loudspeakers. This assembly has a mass of 2.7 kg, emits an average sound pressure level equal to 70.6 dB and has a power of 80.2 mW. Curve (b) illustrates a variation of the sound pressure level with frequency for a glass assembly 1 comprising a first exciter 6 and two second exciters 7. The first exciter 6 and the second exciters 7 have a total mass of 1.06 kg. The glazed assembly 1 emits an average sound pressure level equal to 71.0 dB and has a power of 111 mW.

Claims

Claims

1. Glazed assembly (1) for a vehicle (2) adapted to emit acoustic waves, the glazed assembly (1) comprising a glazing (3), the glazing (3) comprising a first face (4) adapted to be arranged inside the vehicle (2) and a second face (5) adapted to be arranged outside the vehicle (2), the glazed assembly (1) comprising: - at least one first exciter (6) comprising a first connecting part (8) and a first mobile part (9), the first exciter (6) being configured to cause a periodic movement between the first connecting part (8) and the first mobile part (9) by electrical control, the first connecting part (8) being fixedly mounted on the first face (4), the first exciter (6) being adapted so that the movement between the first connecting part (8) and the first mobile part (9) has a frequency equal to 100 Hz, and - at least one second exciter (7) comprising a second connecting part (15) and a second movable part (16), the second exciter (7) being configured to cause a periodic movement between the second connecting part (15) and the second movable part (16) by electrical control, the second connecting part (15) being fixedly mounted on the first face (4), the second exciter (7) being adapted so that the movement between the second connecting part (15) and the second movable part (16) has a frequency equal to 1 kHz, characterized in that: - the first connecting part (8) has a first mass M m , the sum of the first mass(es) M m being between 200 g and 10 kg, and - the glazing (3) having a length L x , a width L yand a thickness h predetermined so that a first natural frequency fn of the glazing is less than 100 Hz, the first natural frequency fi 1 being defined by: where D is the bending stiffness of the glazing (3) expressed in Nm, p is the average mass density of the glazing (3) expressed in kg / m 3 and where: 0.017 and 0.

017.

2. Glazed assembly (1) according to the preceding claim, comprising a plurality of first exciters (6), the sum of the first masses M m being between 200 g and 10 kg. [Claim s] Glazed assembly (1) according to one of the preceding claims, in which the first connecting part (8) comprises a first magnet (17) and the first movable part (9) comprises a first electrically conductive coil (18).

4. Glazed assembly (1) according to claim 3, in which the assembly of the first magnet(s) (17) has a mass M mi between 100 g and 10 kg. [Claim s] Glazed assembly (1) according to one of the preceding claims, in which the second connecting part (15) has a mass M c less than 20 g.

6. Glazed assembly (1) according to one of the preceding claims, comprising a plurality of second exciters (7).

7. Glazed assembly (1) according to one of the preceding claims, in which the second connecting part (15) comprises a second electrically conductive coil (20) and the second movable part (16) comprises a second magnet (19). [Claim s] Glazed assembly (1) according to the preceding claim, in which each second coil (20) has a mass M C 2 less than 20 g.

9. Glazed assembly (1) according to one of the preceding claims, in which the glazing (3) comprises an opaque coating (10), the first exciter(s) (6) and preferably the second exciter(s) exciter(s) (7) being mounted fixedly on the first face (4) opposite the opaque coating (10) or on the opaque coating (10).

10. Glazed assembly (1) according to one of the preceding claims, in which the glazing (3) is a laminated glazing comprising a layer based on poly(vinyl butyral), the layer based on poly(vinyl butyral) comprising a plasticizer, a mass content of the plasticizer in the layer being strictly greater than 28.5%.

11. Vehicle (2) comprising a glazed assembly (1) according to one of the preceding claims, the glazed assembly (1) forming a roof (11) of the vehicle (2).

12. Vehicle (2) according to claim 11, comprising at least one first loudspeaker (12) adapted to emit an acoustic wave having a frequency equal to 10 kHz.

13. Vehicle (2) according to claim 11 or 12, wherein the glazing (3) has natural frequencies, the vehicle (2) comprising a control unit (14) configured to transmit an electrical signal representative of an acoustic signal to the first exciter(s) (6) and / or to the second exciter(s) (7), the control unit (14) comprising a module for transforming an acoustic signal configured to modify a first incoming electrical signal associated with a first acoustic signal into a second outgoing electrical signal associated with a second acoustic signal, so that the second acoustic signal has an amplitude at a natural frequency of the glazing (3) smaller than the amplitude at the same natural frequency of the first acoustic signal.

14. Vehicle (2) according to one of claims 11 to 13, the vehicle (2) comprising a control unit (14) configured to transmit a third electrical signal representative of a third acoustic signal to a second exciter (7), a fourth electrical signal representative of a fourth acoustic signal to another second exciter (7), concomitantly, the third acoustic signal being different from the fourth acoustic signal.

15. Vehicle (2) according to one of claims 11 to 14, comprising a control unit (14) configured to emit an electrical signal representative of an acoustic wave to the first exciter(s) (6) and / or to the second exciter(s) (7), the control unit (14) comprising a synchronization module configured to introduce a delay into the acoustic wave, the delay being predetermined from the location on the first face (4) of the first exciter(s) (6) or of the second exciter(s) (7) to which the electrical signal is emitted.

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