Closed sound receiver with sound-permeable boundary surface

Abstract

The invention relates to a sound receiving arrangement (5) for fastening in an outer layer of an object (1), wherein the outer layer comprises a recess (1V), having the following features: a housing (10) which is arranged in the recess (1V) and forms a cavity (10h); an acoustically permeable boundary surface (14) which closes the cavity (10H); a sound receiver (12) which is arranged in the interior of the housing (10) such that a medium is provided between the sound receiver (12) and the acoustically permeable boundary surface (14).

Description

[0001] Closed sound sensor with sound-permeable interface

[0002] Description

[0003] Embodiments of the present invention relate to a closed sound sensor with a sound-permeable interface (sound recording arrangement) for mounting in an outer shell of an object. Further embodiments relate to a closed acoustic sensor with a sound-permeable interface for sound recording for installation in the outer shell of an object or building outdoors. Areas of application of embodiments include objects such as movable or moveable objects, in particular vehicles, aircraft, and boats, but also buildings. In this respect, further embodiments relate to an outer wall or a wall of a building, as well as to a movable or moveable object with a corresponding sound recording device.

[0004] Recording sound outdoors places special demands on corresponding sensor systems. They must be robust and weatherproof. Furthermore, it is extremely important that such a sensor picks up as little wind noise or airflow noise as possible. A good aerodynamic profile or measures to reduce wind noise therefore play a key role. Sound recording must be ensured.

[0005] If such a sensor is to be installed in objects that are located outdoors or are moved (e.g. a freestanding unit or a vehicle), or in a house facade, the question of how the integration can be carried out effectively becomes even more difficult.

[0006] A common approach is to install a microphone in a housing. The microphone is then connected to the outside air via a sound duct (or more generally an air path). An acoustic membrane can be placed in front of or in this acoustic duct to protect the microphone from moisture and prevent dust or similar substances from entering the duct. We refer to this concept as an "open sensor." The housing is built into or attached to the outer shell of the object. An example of the prior art is DE 102019220204 A1, which discloses a design for a microphone. Problems with such a design arise in strong winds or with induced airflow at high speeds, e.g., when a vehicle is in motion. Wind noise is induced at the sound opening, at edges, and at irregularities.Above a certain wind or object speed, the ratio between the wanted signal and the background noise is so strongly shifted that the sensor cannot be used, even with state-of-the-art noise suppression software. Another problem lies in the robustness of the sensors. (An acoustic membrane is significantly more susceptible to damage than other, stronger / stiffer materials.) We see a third problem in the complexity of the described method, since the clamping of an acoustic membrane is adaptively achieved using appropriate electronics / mechanics.

[0007] Since there is no barrier between the microphone and the outside air (except for an optional acoustic membrane), comparatively good sound recording can be achieved when stationary and in calm conditions.

[0008] An alternative solution is to position the microphones or the entire sensors behind a fixed enclosure, where no currents or strong pressure fluctuations are expected. Furthermore, there are hardly any problems with robustness and weather resistance. In a project in which microphones were installed in a vehicle to detect exterior noise, the following positions were tested, among others:

[0009] Vehicle interior (significant interference from passengers and entertainment system music), exterior mirrors (significant attenuation from mirrors and mirror housings), trunk (significant attenuation from the body), and under the hood (significant interference from the engine and other components). All of these solutions reduce wind noise due to the separating material, but they also significantly impair the useful signals, as the materials do not allow airflow to pass through but also significantly dampen sound waves. Furthermore, the noise from the vehicle itself is absorbed to a greater extent. Therefore, there is a need for an improved approach.

[0010] The object of the present invention is to improve sound measurements using a sound measuring system mounted on the outer skin in terms of recording quality, especially at higher movement speeds, and robustness. This object is achieved by the subject matter of the independent patent claims.

[0011] Embodiments of the present invention provide a sound pickup assembly in (e.g., within) an outer shell of an object, such as a building, an outer wall of a building or wall of a building, or even an outer shell of a movable object such as a vehicle. The outer shell has a recess, e.g., in the sense of a depression or cutout (e.g., a hole into which the sensor with its outer skin and the housing is integrated). The sound pickup assembly has the following features: a housing, an acoustically permeable interface, and a sound pickup.

[0012] The housing is arranged or embedded in the recess, e.g., creating a closed shape. The housing itself can have a hollow shape. The acoustically permeable interface closes off this cavity. The sound sensor is arranged inside the housing or cavity, so that a medium is provided between the sound sensor and the acoustically permeable interface.

[0013] Examples of recesses are a depression in a facade or a hole / recess in the outer skin of a car body / sheet metal.

[0014] It should be noted that the outer shell forms a kind of surface layer of the object and has a recess open to the surface. The acoustically permeable interface separates the housing and the cavity from the environment.

[0015] According to embodiments, the medium comprises, for example, air or a material or other gas. According to embodiments, the acoustically permeable interface forms a continuation of the outer shell of the object. It should be noted that the acoustically permeable interface represents a separate material / object that is flush with the surrounding outer surface. Embodiments of the present invention are based on the finding that, through a corresponding recess, a microphone encapsulated in a housing or, in general, (encapsulated) sound recording means can be arranged in the recess. The closed shape of the housing prevents the penetration of moisture, dust, or other solid objects into the sensor.The recess can also provide an advantage in terms of robustness if the interface develops a hole due to damage, as moisture and dust cannot immediately contact the microphone due to the distance, and moisture can "bead off." This has a beneficial effect on the robustness and longevity of the sensor. In this respect, embodiments of the present invention combine the advantages of a closed system (reduced wind noise, no penetration of moisture or dust) with those of an open system (direct sound path between the outside world and the microphone and thus better transmission of airborne sound).

[0016] By forming a continuation of the outer shell through the acoustically permeable interface, a flat surface can be created for the interface, along with the surrounding boundary of the object, or rather, the outer shell of the object, such as a house facade. Consequently, compared to other solutions, hardly any wind noise is induced at this surface during currents or wind, especially since the currents or wind flow past the surface and are not subject to any unevenness.

[0017] This is especially true when the flow is parallel to the surface. This is especially the case with moving objects at higher speeds, such as vehicles. In our opinion, this property is the greatest and most decisive advantage.

[0018] According to further embodiments, the acoustically permeable interface and / or the outer shell can be coated or painted. Consequently, a further advantage is that the acoustically permeable interface could be painted and thus would no longer be visible in certain objects, e.g., vehicles, if the same paint is used as the boundary.

[0019] According to embodiments, the sound pickup arrangement, in which the medium or at least a portion of the medium is formed by a sound-permeable volume, can have the acoustically permeable interface. This variant makes the acoustically permeable interface significantly more robust.

[0020] According to embodiments, an acoustic insulator, comprising, for example, sand, bitumen, foam, polymer chambers, and / or another material, is provided between the inside of the housing and the sound sensor. This has the advantage that even noises from the object itself, such as from the engine compartment of a vehicle, are picked up by the sound sensor at a reduced level.

[0021] In order to create a coherent connection to the backfill of the outer shell or the outer shell itself, for example in order to select the flat surface or the flat painted surface, according to embodiments the housing can be connected via a rear side of the housing to the outer shell or a backfill of the outer shell or the object.

[0022] At this point, it should be noted that, according to exemplary embodiments, the cavity in the housing, or even the recess in the housing, or even the housing itself, has a funnel-shaped form, for example. The funnel shape, as one of the possible (internal) shapes, is acoustically advantageous in itself, although other shapes are also possible. The sound pickup can, for example, be arranged in the last third of the funnel. In some implementations, the funnel-shaped shape has the technical advantage of already providing a type of acoustic filtering of the sound from background noise.

[0023] Examples of acoustically permeable interfaces are given below. These can include one of the following materials:

[0024] Rigid foam board foiled rigid foam board

[0025] PUR or PIR

[0026] plastic plate

[0027] HDPE high-resistance plastic film

[0028] PMMA, PTFE or PET

[0029] Sheet metal. At this point, it should be noted that sealing elements, such as a rubber lip, can also be provided to optimize the transition between the sound-permeable interface and the outer shell of the object. According to further embodiments, the acoustically permeable interface can be reinforced or stiffened. This can, for example, have stiffened struts. Alternatively, a strut to support the acoustically permeable interface relative to the housing would also be conceivable. In order to combine the advantages of the rubberized or flexible transition to the outer skin and the mounting of the acoustically permeable interface, according to further embodiments, the interface can be mounted by means of a spring-loaded suspension, e.g., mounted relative to the housing.

[0030] As already explained above, according to exemplary embodiments, the outer shell and the acoustically permeable interface form a flat surface with smooth transitions. In the case of a curved outer surface, it would be advantageous if the outer surface were also curved with a corresponding profile. Therefore, according to exemplary embodiments, the acoustically permeable interface can have a curved shape. According to exemplary embodiments, the recess and thus also the housing and the top view of the acoustically permeable interface are, for example, round or oval. This enables stress-free mounting at the bearing points. Theoretically, other shapes (square, etc.) would also be conceivable.

[0031] Further embodiments relate to an external wall as an object or a wall as an object with a sound recording device.

[0032] According to a further embodiment, a movable or movable object, in particular a vehicle, aircraft or boat, is equipped with a sound recording device.

[0033] Embodiments of the present invention are explained below with reference to the accompanying drawings. They show:

[0034] Fig. 1 is a schematic representation of a basic implementation of a sound recording arrangement;

[0035] Fig. 2 is a schematic representation of an expanded embodiment of a sound pickup assembly; and Fig. 3 is a further schematic representation of a sound pickup assembly according to expanded embodiments for discussing optional features.

[0036] Before exemplary embodiments of the present invention are explained below with reference to the accompanying drawings, it should be noted that the same elements and structures are provided with the same reference numerals, so that the description of them is applicable to one another or interchangeable.

[0037] Fig. 1 shows an object 1 which has an object volume and an object surface 1o. The object can be, for example, a house facade or the outer skin of a movable object such as a car. The surface 1o is therefore the uppermost final layer of the object 1. Starting from the surface 10, a recess 1v extends into the object body of the object 1. A device for recording sound with the housing 10 is arranged in the recess 1V. The device for recording sound has a housing 10 with a sound pickup 12, such as a microphone, arranged in the housing 10. The microphone is arranged, for example, on the rear wall of the housing 10, i.e. in the cavity of the housing 10. The housing 10 has an opening 10O opposite the rear side, which opening is arranged on the front of the housing 10, i.e. on the surface that essentially continues the outer surface 10O.Geometrically speaking, this means that the housing opening 10O approximately continues the outer skin 10 of the object 1, while the rear of the housing 10 protrudes into the volume of the object. The sound 20 impinges on the outer skin 10 and the opening 10Ö via the front side. This sound can then be picked up by the microphone 12. According to the exemplary embodiments, the microphone 12 is arranged deep within the housing 10, e.g., in the rear third as seen from the front side 10O.

[0038] The opening 10Ö is closed by an acoustically permeable boundary surface 14, so that the cavity 10H, in which the microphone 12 is located, is encapsulated. Due to the position of the microphone 12 in the cavity 10H or in the rear part of the cavity, a distance is created between the microphone 12 and the acoustically permeable boundary surface 14, which is filled with a medium, such as air or another gas. The acoustically permeable boundary surface 14 is defined, for example, as a flat body that is designed to allow sound to pass through. The acoustic boundary layer can have (as a lower limit), for example, a thickness of at least 0.1 mm, at least 0.5 mm, at least 1 mm, at least 2 mm or even at least 3 mm. Upper limits for the thickness are, for example, 10 mm or 5 mm or 3 mm or 2 mm or 1.5 mm. Of course, filling with a kind of solid or partial solid, such as a foam (with pores, ie open-pore foam) would also be conceivable.In the case of a solid material in the cavity or as the "base" of the acoustic interface, a so-called structure-borne sound sensor would be useful. According to the design examples, "partial" can also mean that the area between the acoustically permeable interface and the sound sensor contains areas not filled with the solid material, in the sense of cavities.

[0039] It should also be noted that the solid material or partially solid material can be connected to the acoustically permeable interface (as a separate element). For example, the acoustically permeable interface can be formed by a sheet metal, painted sheet metal, a paint carrier layer, or a surface element. In other words, the recess can be formed by a surface element (painted sheet metal analogous to the outer skin) or the outer skin itself, which forms the acoustically permeable interface.

[0040] A further embodiment provides a sound pickup arrangement for attachment inside or behind an outer shell of an object, comprising the following features: a housing arranged in a recess behind the outer shell and forming a cavity; an acoustically permeable boundary surface which is part of the outer shell and closes the cavity; a sound pickup arranged inside the housing such that a medium is provided between the sound pickup and the acoustically permeable boundary surface.

[0041] A solid material or partial solid material belonging to the outer shell is provided between the acoustically permeable interface and the housing.

[0042] After the structure has been explained above, the functionality will be discussed below.

[0043] The exterior of the housing 10, i.e., the area where the sound 20 impinges on the sound-permeable membrane 14, is encapsulated by the sound-permeable interface, or generally the interface 14. Due to the sound-permeable properties, the sound pressure is induced onto the interior of the housing 10, i.e., into the cavity 10H, where it can be picked up by the microphone 12. The encapsulation by the permeable interface 14 prevents outside air from coming into contact with the microphone 12, thus ensuring moisture permeability and weather resistance.

[0044] According to embodiments, the sound-permeable interface 14 can continue the surface 100 accordingly or even be a flat one. This prevents collateral noise from occurring at the transitions between the housing 10 and the object 1. Sealing elements (not shown) can also be provided for this purpose, according to embodiments. Regarding the sound-permeable membrane 14, it should be noted that, according to preferred embodiments, it is made of a material that is solid, robust, impermeable to moisture, and weather-resistant, yet still sufficiently acoustically permeable. For this reason, the surface is referred to as an acoustically permeable interface.With regard to the media present on the outside and inside, it should be noted that the acoustically permeable interface can, for example, come into contact with air on both the outside and the inside, whereby, according to further embodiments, other media, such as a gas, an inert gas, or even a fluid, can also be used.

[0045] Regarding the microphone, it should be noted that it converts the sound 20 arriving inside the housing 10 into an electrical signal. Depending on the embodiments, additional electronics can also be provided in addition to the actual sensor. Typically, the electrical signal, or the electrical signal preprocessed by the electronics, is routed out of the housing 10 via a cable. Wireless transmission, e.g., via radio, is also conceivable.

[0046] An extended embodiment is shown below with reference to Fig. 2.

[0047] Fig. 2 shows a sound pickup assembly 5 with a housing 10, an inner housing 10, and a cavity 10H of the microphone 12 arranged in the housing, wherein the cavity 10H is encapsulated by the acoustically permeable membrane 14. The housing 10 is embedded in an intermediate material 2 of the object 1, wherein an inner boundary 2i and an outer boundary 2a are provided in the object 1.

[0048] A recess / hole of suitable shape is provided in the boundary 2 and 2a of a movable or immobile object 1 or a building façade, which is in contact with the outside air and into which the acoustic sensor is to be installed. The housing 10 is inserted into this recess. According to embodiments, the recess is usually, but not necessarily, circular. The housing 10 is usually, but not necessarily, inserted into this recess from the inside. According to embodiments, the housing 10 is usually, but not necessarily, attached from the inside to the boundary 2a and 2i of the object or to the building façade.

[0049] According to a preferred but not mandatory embodiment, the acoustically permeable boundary surface 14 forms a flat surface together with the surrounding boundary 2a of the object 1 or the house facade. The surface 14 is formed from an acoustically permeable material and can be curved or otherwise shaped according to embodiments, for example, corresponding to the boundary 2a of the object 1 or the house facade.

[0050] The housing 10 optionally includes acoustic insulation 22 facing the inside of the object 1 or the building 10 in order to suppress noise from the object 1 or the building itself. This acoustic insulation 22 can be implemented in various ways and is therefore not limited to a specific implementation. One embodiment consists of a filling made of sand, bitumen, foam, or other materials. Another embodiment consists of several successive air chambers, which can also be filled with foam, sand, or similar material. Another type of implementation consists of layers of different materials having different resonant frequencies, with or without additional air cushions between the layers.

[0051] According to embodiments, the inner side of the housing 10, in which the sound sensor 12 is placed, can take on various shapes. An acoustically favorable shape that enables optimized sound pickup, e.g., a funnel, is preferred.

[0052] At this point it should be noted that, according to exemplary embodiments, rigid foam panels made of PUR / PIR with or without additional film coating on the surface, for example of the Kapa brand, are suitable as materials for the acoustically permeable interface 14. Also suitable would be various rigid (i.e. non-flexible) plastics, i.e. a thin plastic panel such as HDPE. Various highly resistant plastic films made of materials such as PMMA, PTFE or PET would also be conceivable. A thin sheet of metal would also be conceivable. The invention is not limited to specific material groups. The materials mentioned represent examples or different embodiments. All materials that meet the above requirements are also part of this invention. In any case, the thickness of the interface is critical. It represents a compromise between robustness or mechanical stability and acoustic permeability.

[0053] Regarding the sound sensor: This converts acoustic sound into an electrical voltage or current. All transducer principles are possible. In some embodiments, part of the acoustic sensor can be additional electronics, which is installed in the housing (H). An electronic interface can be part of the sensor. This interface usually, but not necessarily, leads into the interior of the object. It would also be conceivable for cables to lead directly from the housing into the interior of the object or house. Wireless transmission of the acoustic signals would also be conceivable.

[0054] Regarding the arrangement of the acoustically permeable boundary surface 14 and the surrounding boundaries 2a of the object or the building facade, it should be noted that these preferably form a flat surface, i.e., they are designed to be flush. Thus, compared to other solutions, hardly any wind noise is induced on these surfaces during currents or wind, since the currents or wind flow past the surface and are not subject to any unevenness.

[0055] Regarding the signal quality according to this teaching, it should be noted that the exemplary embodiment creates a compromise between the closed and open systems. Compared to the open system in calm conditions, the transmission of airborne sound (with the materials we have in mind) is poorer (e.g., a porous rigid foam board is still a solid material; pores nevertheless enable better sound transmission than other solid materials, but poorer transmission than a pure air duct or acoustic membrane). However, transmission is improved in conditions such as wind.

[0056] In another embodiment, the acoustically permeable interface 14 is supported from behind (i.e., from the side facing the object or on the side where the sound sensor is located) by struts made of other materials, such as sheet metal or steel. This increases the rigidity and mechanical strength of the interface. The support can be designed in a grid-like manner, for example. The support could enable a thinner interface compared to the one without support, which would allow sound to pass through better without compromising the mechanical strength.

[0057] These supports can therefore extend parallel to the acoustic interface 14 as reinforcing structures in the form of beams or a grid arrangement. Alternatively, it would also be conceivable to support the surface 14 against the rear of the housing 10 by vertical or transverse supports.

[0058] With reference to Fig. 3, a further embodiment is explained, wherein it should already be noted at this point that the basic structure of variant 1' from Fig. 3 corresponds to variant 1 from Fig. 2, but in addition there are also further optional features.

[0059] In a further embodiment, the medium 26 between the sound-permeable interface 14' and the sound sensor 12 consists of a solid material that can conduct structure-borne sound sufficiently well. In this embodiment, the sound sensor 12 corresponds, for example, to a structure-borne sound sensor or acceleration sensor attached to this intermediate material. In a further embodiment, this intermediate material can be identical to the material of the sound-permeable interface; the sound-permeable interface is replaced by a sound-permeable volume.

[0060] In this respect, in this embodiment, the cavity 26 is filled by a structure that also improves the mechanical robustness of the acoustically permeable interface 14'.

[0061] Further variants consist of an adaptation of all previously mentioned variants by additionally painting the acoustically permeable interface 14'.

[0062] This means that the acoustically permeable boundary surface 14' or the outer skin 2a' is coated with a paint 28. Typically, but not necessarily, the same paint is used as for the surrounding boundary, if this surrounding boundary is coated. Further embodiments / examples result from an adaptation of all the previously mentioned embodiments, in which the housing (excluding the sound-permeable boundary surface, if present) is spring-mounted to achieve better acoustic decoupling from the inherent noise of the object or house, if this decoupling should be advantageous for the application.

[0063] Further embodiments / embodiments result from an adaptation of all previously mentioned embodiments, in which an acoustically insulating layer is additionally placed between the acoustically permeable boundary surface and the boundary or the housing 10 or both, e.g. in the form of a rubber lip, in order to achieve better acoustic decoupling from the boundary of the object or the house facade, if this insulation should be advantageous in the application.

[0064] Below, a preferred variant (corresponding to an exemplary embodiment) is explained based on the basic features and optional features explained above. The structure essentially corresponds to that discussed in Fig. 1, with the following additions / variations:

[0065] • Microphone as a sound pickup

[0066] • Foil-coated rigid foam board with additional coating as an acoustically permeable interface

[0067] • Circular acoustically permeable interface

[0068] • Acoustically permeable interface forms a flat, smooth surface together with the boundary

[0069] • Funnel-shaped housing interior

[0070] • Microphone in the center of the funnel

[0071] • Without rubber lip or spring suspension

[0072] • Sand as acoustic insulation

[0073] Applications for embodiments of the present invention are:

[0074] • Topic area “the hearing car” o Acoustic external perception / environment detection o Detection of tire rolling noise (road surface detection) o Detection of the vehicle’s own noise (self-diagnosis, condition monitoring) o and much more

[0075] • Detection of environmental noises • Acoustic monitoring of roads

[0076] • Theft protection of freestanding objects (recording of speech and sounds in case of attempted theft)

[0077] • Recording environmental noise while simultaneously recording noise from the object itself

[0078] List of reference symbols

[0079] 12 microphones 10 housings including holders including waveguides

[0080] 14 acoustically permeable boundary

[0081] 22 acoustic insulation / decoupling

[0082] 2I, 2A boundary

[0083] 10H Cavity, e.g. air 2 Inner material

Claims

Patent claims 1. Sound receiving arrangement (5) for mounting within an outer shell (10) of an object (1), wherein the outer shell (10) has a recess (1V) with the following features: a housing (10) arranged in the recess (1V) forming a cavity (10h); an acoustically permeable interface (14) closing the cavity (10h); a sound transducer (12) arranged inside the housing (10) such that a medium is provided between the sound transducer (12) and the acoustically permeable interface (14); wherein a solid material or partial solid material belonging to the outer shell (10) is provided between the acoustically permeable interface (14) and the housing (10).

2. Sound recording arrangement (5) according to claim 1, wherein the acoustically transparent interface (14) forms a continuation of the outer shell (10).

3. Sound recording arrangement (5) according to one of the preceding claims, wherein the medium or at least a part of the medium is formed by a sound-permeable volume having the acoustically permeable interface (14).

4. Sound recording arrangement (5) according to one of the preceding claims, wherein an acoustic isolator is provided between an inner side of the housing (10) and the sound sensor (12), in particular an acoustic isolator comprising sand, bitumen, foam, polymer chambers; and / or wherein the inner side of the housing (10) is acoustically insulated.

5. Sound recording arrangement (5) according to one of the preceding claims, wherein the housing (10) is connected via a rear side of the housing (10) to the outer shell (10) or a backfill of the outer shell (10) or to the object (1).

6. Sound recording arrangement (5) according to one of the preceding claims, wherein the recess (1V) and / or the cavity (10h) of the housing (10) has a funnel shape.

7. Sound recording device according to one of the preceding claims, wherein the acoustically transparent interface (14) comprises one of the following materials: laminated rigid foam board rigid foam board PUR or PIR plastic sheet HDPE high-resistance plastic film PMMA, PTFE or PET sheet metal.

8. Sound recording arrangement (5) according to one of the preceding claims, wherein the acoustically transparent interface (14) and / or the outer shell (10) has a coating.

9. Sound recording device according to one of the preceding claims, which further comprises at least one rubber lip provided at the transition between the acoustically permeable interface (14) and the outer shell (10).

10. Sound recording device according to one of the preceding claims, wherein the acoustically transparent interface (14) is connected to the housing (10) by a spring-loaded suspension and / or bearing.

11. Sound recording device according to one of the preceding claims, wherein the solid material or partial solid material comprises or forms the acoustically transparent interface (14); wherein the solid material or partial solid material is connected to the acoustically permeable interface (14) or wherein the solid material or partial solid material is connected to the acoustically permeable interface (14) and wherein the acoustically permeable interface (14) is formed by a sheet, painted sheet, a paint substrate layer or a surface element.

12. Sound recording arrangement (5) according to one of the preceding claims, wherein the acoustically transparent interface (14) is curved and / or projects out of the plane or into the plane; and / or wherein the acoustically transparent interface (14) and / or the housing (10) and / or the recess (1V) are circular.

13. Sound recording arrangement (5) according to one of the preceding claims, wherein the outer shell (10) and the acoustically permeable interface (14) form a plane or curved planes or surface or curved surface.

14. Sound recording arrangement (5) for mounting behind an outer shell (10) of an object (1), comprising: a housing (10) arranged in a recess (1V) behind the outer shell (10) and forming a cavity (10h); an acoustically permeable interface (14) that is part of the outer shell (10) and closes the cavity (10h); a sound transducer (12) arranged inside the housing (10) such that a medium is provided between the sound transducer (12) and the acoustically permeable interface (14); wherein a solid material or partial solid material is provided between the acoustically permeable interface (14) and the housing (10). Exterior wall as object (1) or wall as object (1) with a sound recording device according to one of the preceding claims. Movable or movable object (1), in particular vehicle, aircraft or boat with a sound recording device according to one of the preceding claims.

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