EP4675610A1

EP4675610A1 - Acoustic control module

Info

Publication number: EP4675610A1
Application number: EP24275078.4A
Authority: EP
Inventors: designation of the inventor has not yet been filed The
Original assignee: BAE Systems PLC
Current assignee: BAE Systems PLC
Priority date: 2024-07-01
Filing date: 2024-07-01
Publication date: 2026-01-07

Abstract

According to the present disclosure there is provided an acoustic control system comprising: an acoustic control module comprising a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open; a closing member arrangement, wherein the module and the closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators; and a control mechanism arrangement provided in communication with the Helmholtz resonator portion arrangement of the acoustic control module for controlling an operation characteristic of the one or more Helmholtz resonators.

Description

FIELD

The present invention relates to an acoustic control module, in particular an acoustic control module for an acoustic control system. The present invention further relates to an acoustic control system, an apparatus, a kit of parts, and a method of manufacture of an acoustic control system.

BACKGROUND

Acoustic control modules and systems are used to control, or absorb, acoustic noise. Acoustic noise may be known as "airborne noise". A typical acoustic control module or system may incorporate a Helmholtz resonator (otherwise known as a Helmholtz absorber). A Helmholtz resonator is a type of resonant absorber. A volume of air within a Helmholtz resonator may be vibrated to produce a tone at its natural frequency of resonance. Absorption of acoustic noise is maximal at the frequency of resonance, and decreases at nearby frequencies. For maximal effectiveness, Helmholtz resonators should be placed in areas of high modal sound pressure for the tuned frequency.
A conventional Helmholtz resonator comprises a neck (or port) and a cavity. The neck is in communication with the cavity at one end, and has an aperture, hole, or opening at the other end. The aperture of the neck remains open, as it is by this means that air within the cavity may be vibrated.
Challenges are faced where the sound field includes a variety of frequencies. The sound impinging on a Helmholtz resonator that is not absorbed may be reradiated. Unabsorbed energy may be diffused, and the diffusion of uncontrolled sound is undesired in a sound-controlled environment, such as a studio or listening room. Furthermore, it is not always desirable to manufacture acoustic control modules that are specifically configured to the acoustic noise present in a sound-controlled environment, and a level of adjustability or reconfigurability is often desirable but is not achievable using conventional approaches.
It is an object of the present invention to provide an improved acoustic control module, acoustic control system, apparatus, kit of parts and/or a method. Alternatively, or additionally, it is an object of the present invention to address one or more of the problems discussed above, or discussed elsewhere, or to at least provide an alternative module, system, apparatus, kit and/or method.

SUMMARY

According to a first aspect of the present invention, there is provided an acoustic control module for an acoustic control system, the module comprising: a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open, wherein the module and a closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators.
In one example, the Helmholtz resonator portion arrangement comprises a plurality of Helmholtz resonator portions.
In one example, each Helmholtz resonator portion has a different cavity portion size and/or a different neck portion size.
In one example, the module comprises a body, the body comprising one or more outer faces, and wherein the one or more Helmholtz resonator portions extend into the body from the one or more outer faces thereof.
In one example, the one or more Helmholtz resonator portions are provided at: one or more side faces or surfaces of the body; and/or one or more edges of the body.
In one example, the body has the form of a tesselatable polyhedron, preferably a cuboid.
According to a second aspect of the present invention, there is provided an acoustic control system comprising: an acoustic control module according to the first aspect; and a closing member arrangement.
In one example, the closing member arrangement comprises one or more additional acoustic control modules according to the first aspect.
In one example, the acoustic control module is located relative to an additional acoustic control module of the closing member arrangement, so that a Helmholtz resonator portion of the additional acoustic control module of the closing member arrangement closes the Helmholtz resonator portion of the acoustic control module.
In one example, the Helmholtz resonator portion of the additional acoustic control module of the closing member arrangement has the same cavity portion size and/or neck portion size as that of the Helmholtz resonator portion that it closes.
In one example, the Helmholtz resonator portion of the additional acoustic control module of the closing member arrangement has a different cavity portion size and/or neck portion size as to that of the Helmholtz resonator portion that it closes.
In one example, the system comprises a plurality of additional acoustic control modules, wherein each of the plurality of Helmholtz resonator portions of the acoustic control module is closed by a Helmholtz resonator portion of an additional acoustic control module of the plurality of additional acoustic control modules.
According to a third aspect of the present invention, there is provided an apparatus comprising: the acoustic control module according to the first aspect; and a noise generating component, wherein the noise generating component provides the closing member arrangement, or the acoustic control system according to the second aspect; and a noise generating component.
According to a fourth aspect of the present invention, there is provided a kit of parts for an acoustic control system, the kit comprising: at least one acoustic control module according to the first aspect; and a closing member arrangement.
According to a fifth aspect of the present invention, there is provided a method of manufacture of an acoustic control system using an acoustic control module comprising: a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open, the method comprising: locating the module and a closing member arrangement relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators.
According to a sixth aspect of the present invention, there is provided an acoustic control system comprising: an acoustic control module comprising a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open; a closing member arrangement, wherein the module and the closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators; and a control mechanism arrangement provided in communication with the Helmholtz resonator portion arrangement of the acoustic control module for controlling an operation characteristic of the one or more Helmholtz resonators.
In one example, the control mechanism arrangement is provided in communication with the Helmholtz resonator portion arrangement such that an operation characteristic is controllable. In one example, the control mechanism arrangement is configured to, or is able to, function or operate so as to control the operation characteristic.
In one example, the closing member arrangement comprises one or more additional acoustic control modules and/or one or more closing members.
In one example, the acoustic control module is located relative to an additional acoustic control module of the closing member arrangement, so that a Helmholtz resonator portion of the additional acoustic control module of the closing member arrangement closes the Helmholtz resonator portion of the acoustic control module.
In one example, the operation characteristic is: resonance frequency; level of attenuation; and/or level of energy dissipation.
In one example, the control mechanism arrangement comprises a component arranged to occupy a volume within the cavity portion and/or neck portion, the component being adjustable so as to control the size of the volume, thereby to increase or decrease a free space volume within the cavity portion and/or neck portion.
In one example, the control mechanism arrangement is in the form of an adjustable neck portion, optionally a telescopic neck, and/or an adjustable neck aperture.
In one example, the control mechanism arrangement comprises a sensor for sensing an acoustic frequency in a region proximal to the module, wherein the control mechanism arrangement is arranged to control the operation characteristic based on the sensed acoustic frequency.
In one example, the control mechanism arrangement comprises a communication arrangement between two or more Helmholtz resonators. The communication arrangement may be selectively operable to enable communication between the resonators, thereby to control the operation characteristic.
In one example, the communication arrangement is a controllable conduit arrangement which is selectively operable to provide a fluid flow path between two or more Helmholtz resonators, thereby to control the operation characteristic.
In one example, the control mechanism arrangement comprises a blocking member arrangement provided within the cavity portion, the blocking member arrangement being selectively operable to divide the cavity portion into a first region which is coupled with neck portion and a second region which is decoupled from the neck portion. In an example, the first region may be a region which is in communication with the neck portion, and the second region may be a region which is out of communication with the neck portion.
In one example, the blocking member arrangement comprises: a moveable membrane; and/or a container having a variable internal volume.
In one example, the control mechanism arrangement comprises a fluid supply assembly arranged to supply fluid into the cavity, thereby to adjust the volume of air in the cavity.
According to a seventh aspect of the present invention, there is provided an apparatus comprising: the acoustic control system according to the sixth aspect; and a noise generating component.
In one example, the noise generating component provides the closing member arrangement.
According to an eighth aspect of the present invention, there is provided an acoustic control module for an acoustic control system, the module comprising: a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open, wherein the module and a closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators, wherein the Helmholtz resonator portion arrangement is providable in communication with a control mechanism arrangement for controlling an operation characteristic of the one or more Helmholtz resonators.
According to a ninth aspect of the present invention, there is provided a kit of parts for an acoustic control system, the kit comprising: at least one acoustic control module according to the eighth aspect; a closing member arrangement; and a control mechanism arrangement for controlling an operation characteristic of the one or more Helmholtz resonators.
According to a tenth aspect of the present invention, there is provided a method of manufacture of an acoustic control system using an acoustic control module comprising: a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open, the method comprising: locating the module and a closing member arrangement relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators; and providing a control mechanism arrangement in communication with the Helmholtz resonator portion arrangement of the module for controlling an operation characteristic of the one or more Helmholtz resonators.
Features of any one of the aspects of the present invention may be combined with features of any other aspect of the present invention, as desired or as appropriate.

BRIEF DESCRIPTION OF THE FIGURES

Embodiments of the invention will now be described by way of example only with reference to the figures, in which:

Figure 1 shows an acoustic control module;
Figure 2 shows a cross sectional view of the acoustic control module of Figure 1;
Figure 3 shows an acoustic control system;
Figure 4 shows an acoustic control system;
Figure 5 shows a schematic apparatus;
Figure 6 shows a schematic kit of parts;
Figure 7 shows general methodology principles;
Figure 8 shows an acoustic control system;
Figure 9 shows a schematic apparatus;
Figure 10 shows an acoustic control module;
Figure 11 shows a schematic kit of parts; and
Figure 12 shows general methodology principles.

DETAILED DESCRIPTION

In summary, the disclosure provided herein relates to an acoustic control module comprising a Helmholtz resonator portion which is at least partially open. By closing the Helmholtz resonator portion, a Helmholtz resonator can be formed. A key feature is the provision of one or more "open" Helmholtz resonator portions, which enables selective closure of the Helmholtz resonator portions, providing advantages in enabling the module to be configured as-required for the particular use-case or environment in which the module is to be employed, to control target acoustic noise frequencies. A "target acoustic noise frequency" may be a frequency of acoustic noise that it is desired to control, and which may be present or generated in the environment in which the acoustic control module or system is deployed.
Referring to Figures 1 and 2, an acoustic control module 100 according to a first embodiment is shown. The acoustic control module 100 is for controlling acoustic noise, or typically airborne or fluid-borne noise - that is, a vibration of gas (typically air) or other fluid (typically water) particles. In this regard, the acoustic control module 100 may otherwise be referred to as an "airborne noise (ABN) control module" or "fluid borne noise (FBN) control module".
The acoustic control module 100 is in the form of a block or individual unit. This allows the module 100 to be assembled with one or more additional components to form a system, or structure, providing one or more (closed) Helmholtz resonators for controlling one or more target acoustic noise frequencies. The acoustic control module 100 is for an acoustic control system 1000.
The acoustic control module 100 comprises a Helmholtz resonator (HR) portion arrangement 110. The HR portion arrangement 110 comprises one or more HR portions 112. Each HR portion 112 comprises a cavity portion 114 and a neck portion 116. Applicable to all examples described herein, whilst the neck portions 116 are shown as having a semi-circular cross section (which may form circular necks when part of a system 1000), the neck portions 116 (and necks) may alternatively have a different shape, e.g., a rectangular or square cross section. Applicable to all examples described herein, whilst the cavity portions 114 are shown as having a half-spherical form (which may form spherical cavities when part of a system 1000), the cavity portions 114 (and cavities) may have alternative forms, for example cuboid (e.g., cube) form.
Each HR portion 112 is at least partially open. By being "at least partially open", it will be appreciated that this does not mean the opening or aperture of the neck in a formed HR, as is the conventional construction of a HR. Rather, the nature of the "open" HR portion is such that the HR portion can be closed to form a HR. The HR portion 112 may be open at a side surface, or at an edge, as will be appreciated from the description herein relating to the closing of the HR portions 112.
The module 100 and a closing member arrangement 200 are locatable relative to one another thereby to close one or more of the one or more HR portions 112 to form one or more Helmholtz resonators (HRs). In other words, by relatively locating the module 100 and the closing member arrangement 200 the open HR portions 112 can be closed, or "completed", thereby to form one or more HRs that are able to control acoustic noise. Advantageously, the particular HR portion or portions 112 of the module 100 which are closed, or selected to be closed, is the choice of the installer or manufacture of the acoustic control system 1000. In this way, one or more particular HR portion 112 may be chosen to be closed based on a matching between a target frequency of noise to be controlled in the environment and the frequency, or frequencies, that the particular HR or HRs are suited to control (i.e., the resonance frequency of the each HR or HRs).
As will be described in greater detail below, the closing member arrangement 200 may comprise one or more closing members. A closing member may be, or comprise a surface of a component (for example, a noise generating component), a plate, a structure, or highly advantageously may be an additional acoustic control module 100. In this way, a plurality of acoustic control modules 100 may be located relative to one another to form an array comprising one or more HRs configured to control one or more desired frequencies.
The module 100 and closing member arrangement 200 may be locatable relative to one another thereby to close one or more of the one or more HR portions 112, to form a sealed connection between the module 100 and closing member arrangement 200 (including between the module 100 and one or more closing members, including with other acoustic control modules 100). Forming a sealed connection may include forming an air-tight connection therebetween. This may be achieved in many ways, which will be well understood by those skilled in the art. For example, gaskets may be used to seal the module 100 and closing member arrangement 200. Additionally, or alternatively, adhesives may be used. Furthermore, the module 100 and closing member arrangement 200 may engage one another thereby to provide a connection by use of engaging elements, such as tabs, fixtures, or the like.
The structure of the module 100 will now be described in greater detail with reference to Figures 1 and 2.
The module 100 comprises a body 150. The body 150 may be a solid body or a hollow body (as illustrated in the cross-section shown in Figure 2). The body 150 comprises one or more outer faces 152. The one or more HR portions 112 extend into the body 150 from the one or more outer faces 152 thereof. In this way, the HR portions 112 are contained within the body 150, and are appropriately positioned to be closed by the closing member arrangement 200. For avoidance of doubt, the one or more outer faces 15 may be defined by one or more outer surfaces of the body 150. The body 150 may take numerous forms, as desired or as appropriate. For example, the body 150 may be provided by a part, section, or region of a component, or may be a plate or planar element. However, in a highly preferred example, the body 150 has the form of a tesselatable polyhedron. A cuboid or hexagonal prism are examples of suitable tesselatable polyhedra. This enables multiple modules 100 to be located relative to one another to form an system (e.g., in the form of an array of modules 100) providing one or more closed HRs, as introduced above and as will be described in further detail later in the description.
The body 150 may be formed from any suitable material. Suitable materials include metals, plastics, rubbers and/or composites. In an example, the entire body 150 is formed of a single material. In another example, different faces 152 of the body may be formed from different materials.
The HR portion arrangement 110 comprises a plurality of HR portions 112. Advantageously, in this way, multiple HRs can be formed by appropriate location of the closing member arrangement 200, and/or one or more particular HR portions 112 of the plurality can be chosen to be closed depending on target frequency or frequencies.
In an example, each HR portion 112 has a different cavity portion size and/or a different neck portion size. In other words, the module 100 comprises a variety of HR portions 112 of differing sizes of cavity portions 114 and neck portions 116. The cavity portion size and neck portion size may refer to the dimensions of the cavity portion and neck portion. It will be understood that use of different size cavity portions and neck portions enables HRs of different sizes, or dimensions, to be formed when closed using the closing member arrangement. In this way, closure of each different HR portion 112 (for example using the same closing member, or using a correspondingly sized HR portion as a closing member) results in the formation of differently sized HRs. Consequently, the module 100 can be used to form HRs of different resonance frequencies, thereby providing for control of different target frequencies of acoustic noise.
The one or more HR portions 112 are provided at one or more side faces, or surfaces, of the body 150. Additionally, or alternatively, the one or more HR portions 112 are provided at one or more edges of the body 150. In a preferred example, HR portions 112 are provided at side faces and also at edges of the body 150. In the example illustrated in Figures 1 and 2, a HR portion 112 is provided at each of the four side surfaces of the cuboid body 150, and a HR portion 112 is also provided at each of the four edges of the cuboid body 150.
In a highly advantageous embodiment described in greater detail below, a system is provided comprising a plurality of acoustic control modules 100. It will be understood from the illustrated example that if each module 100 incorporates four side HR portions 112 each of differing dimension, then there are a possible 14 combinations for HR dimension formed by closing each respective HR portion 112 (including 10 combinations with other HR portions 112 of the additional module 100, plus an additional 4 when closed using a planar surface). Additionally, it will be understood from the illustrated example that if each module 100 incorporates four corner, or edge, HR portions 112 each of differing dimension, then there a possible 69 combinations for HR dimension formed by closing the HR portion 112. In this way, by the above-described construction of the module 100, the modules 100 are combinable to provide 83 different HR dimensions, and thus a possible 83 different HR resonance frequencies enabling control of a possible 67 target frequencies (otherwise known as "target frequency tones") when assembled to form the system 1000.
In a further highly advantageous example, the HR portions 112 may have the same dimension, or a plurality of HR portions 112 of the HR portion arrangement 110 may have the same dimension. In this way, there will be fewer possible target frequencies when assembled to form the system 1000, but the maximum level of absorption, or noise attenuation, may be increased.
In addition to the HR portions 112, the module 100 further comprises an integral HR 160 which is closed, or completed, without use of a closing member. Unlike the HR portions 112, which are to be closed by the closing member arrangement 200 to form HRs, the integral HR 160 is already closed and is configured to control a target frequency. The integral HR 160 comprises a neck and a cavity. The integral HR 160 is provided within the body 150. The integral HR 160 may be configured (i.e., sized) to control a dominant frequency of acoustic noise in the environment in which the module 100 or system 1000 is to be deployed. It will be appreciated that the integral HR 160 is not illustrated in Figure 2.
With the addition of the target frequency control of the integral HR 160, a total of 68 target frequencies may be controllable by appropriate assembly of the system 1000, based on a single part or unit design.
Referring to Figures 3 and 4, a first embodiment and a second embodiment of an acoustic control system 1000 is shown respectively. The acoustic control system 1000 comprises an acoustic control module 100 and a closing member arrangement 200. The acoustic control module 100 may be as described above with reference to Figures 1 and 2. The acoustic control system 1000 may comprise one or more acoustic control modules 100. The closing member arrangement 200 may comprise one or more closing members. The one or more acoustic control modules 100 may provide the closing member arrangement 200.
Referring to Figure 3, in the first embodiment, the acoustic control system 1000 comprises an acoustic control module 100 and a closing member arrangement 200. As described above, the module 100 and closing member arrangement 200 are locatable relative to one another thereby to close one or more of the one or more HR portions 112 to form one or more HRs. The closing member arrangement 200 comprises closing member 210. In the illustrated example, the closing member 210 is in the form of a plate 210. However, it will be appreciated that the closing member may have an alternative form as described above, for example may be, or comprise, a surface of a component (for example, a noise generating component), a plate, a structure, or may be a part, section, surface, or region thereof.
In the illustrated example, the plate 210 is located relative to the module 100 to close one of the HR portions 112 to form a HR (not visible in Figure 3, due to provision of the closing member 210). The HR (i.e., the closed HR) is indicated generally at 115. Whilst not illustrated in Figure 3, the closing member 210 may also comprise a cavity portion and neck portion, which may be correspondingly sized to match that of the HR portion 112 to which it is relatively located (e.g., aligned) to close. Furthermore, whilst not illustrated in Figure 3, the system 1000 may comprise a plurality of modules 100, which may be arranged to form an array, and one or more closing members 210 may be located relative to the array of modules 100. Furthermore, whilst not illustrated in Figure 3, the closing member arrangement 200 may comprise a plurality of closing members 210, and each closing member may close one or more HR portions 112. Advantageously, in this way, a plurality of HRs may be formed, possibly using a single module 100.
Referring to Figure 4, in the second embodiment, the acoustic control system 1000 comprises an acoustic control module 100 and a closing member arrangement 200. As described above, the module 100 and closing member arrangement 200 are locatable relative to one another thereby to close one or more of the one or more HR portions 112 to form one or more HRs.
The second embodiment relates to a highly advantageous embodiment of the present disclosure. In summary, the closing member arrangement 200 comprises, or is provided by, one or more additional acoustic control modules 100 (otherwise known as "closing acoustic control modules", or "closure modules"). In an example, all modules 100 are identical - that is, the module 100 and closure modules 100 all have the same construction. It will be appreciated that by locating (e.g., orientating) the modules 100 relative to one another, one or more HRs can be formed. As the modules 100 incorporate cavity and neck portions of different sizes, the arrangement of the modules 100 forms or creates HRs configured to control target frequencies. The assembler can therefore relatively locate the modules 100 thereby to form a system 1000 capable of controlling desired target frequencies of acoustic noise. In Figure 4, the HRs (i.e., the closed HRs) are indicated generally at 115, where each of the HRs have different dimensions, and therefore are able to each control a different target frequency. However, as discussed above, there may be multiple HRs of the same dimension, thereby enabling a higher level of absorption, or attenuation, of acoustic noise.
The acoustic control module 100 is located relative to the closure module 100 so that a HR portion 112 of the closure module closes the HR portion 112 of the acoustic control module 100. That is, a HR portion 112 of the closure module 100 is used to close the HR portion 112 of the module 100, thereby to form a (closed, or complete) HR. In other words, a HR portion 112 of one module 100 and a HR portion 112 of another module 100 are brought together and connected to form a HR. In this way, HRs are formable by relative location of two or more modules 100.
In one instance, the HR portion 112 of the closure module 100 has the same cavity portion size and/or neck portion size as that of the HR portion 112 that it closes. In other words, the HR portion 112 of one module 100 and the HR portion 112 of another module 100 that are brought together and connected to form a HR have corresponding, or identical, dimensions. In this way, a robust connection between the two HR portions 112 is provided, and/or a reliable frequency control by the completed HR is enabled.
In another instance, the HR portion 112 of the closure module 100 has a different cavity portion size and/or neck portion size as that of the HR portion 112 that it closes. In other words, the HR portion 112 of one module 100 and the HR portion 112 of another module 100 that are brought together and connected to form a HR have different dimensions. In this way, more flexibility, or a wider variety, of controllable frequencies is provided for.
Of course, it will be appreciated that the system 1000 may comprise a combination of the two instances described above.
Features of the first and second embodiment of the acoustic control system 1000 shown in Figures 3 and 4 may be combined. In an example, the acoustic control system 1000 may comprise a plurality of modules 100 as described with reference to Figure 4, and one or more closing members as described with reference to Figure 3 may be used to close one or more open HR portions 112.
Referring to Figure 5, a schematic apparatus 500 is shown.
In one example, the apparatus 500 comprises an acoustic control module 100 according to any of the embodiments described herein. The apparatus 500 further comprises a noise generating component 510. The noise generating component 510 provides the closing member arrangement 200. The noise generating component 510 may be, for example, a vehicle component, an engine, a propulsion system, or may be a vibrating structure, such as a wall, piece of equipment or furniture, etc. The noise generating component 510 may form part of a vehicle, such as a vehicle cabin or hull.
In another example, the apparatus 500 comprises an acoustic control system 1000 according to an embodiment described herein. The apparatus 500 further comprises a noise generating component 510.
The apparatus 500 may further comprise a closing member arrangement 200 (i.e., not as part of the noise generating component 510).
Referring to Figure 6, a schematic kit of parts 600 is shown. The kit of parts is for, or is for forming, an acoustic control system 1000 according to an embodiment described herein. The kit 600 comprises at least one acoustic control module 100 according to an embodiment described herein. The kit 600 further comprises a closing member arrangement 200.
Referring to Figure 7, a method of manufacture of an acoustic control system is shown. The method uses an acoustic control module comprising a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open. Step S710 comprises locating the module and a closing member arrangement relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators. The method may incorporate any of the features described above, as desired or as appropriate.
Referring now to Figure 8, an acoustic control system 8000 according to a third embodiment is shown. The third embodiment may incorporate any features of the first embodiment and/or second embodiment, as desired or as appropriate.
The acoustic control system 8000 comprises an acoustic control module 100 and a closing member arrangement 200, according to embodiments described above. Features thereof will not be repeated here for conciseness, although it will be appreciated that any features of the above-described embodiments, including of the module 100 and system 1000, may be incorporated in the system 8000 as desired or as appropriate.
For completeness, and as described above, the acoustic control module 100 comprises a HR portion arrangement 110 comprising one or more HR portions 112. Each HR portion 112 comprises a cavity portion 114 and a neck portion 116. Each HR portion 112 is at least partially open. The module and the closing member arrangement 200 are locatable relative to one another thereby to close one or more of the one or more HR portions 112 to form one or more HRs. A HR (i.e., a closed HR) is indicated generally at 115.
Notably, in the acoustic control system 8000 according to the third embodiment, the system 8000 further comprises a control mechanism arrangement 810. The control mechanism arrangement 810 is provided in communication with the HR portion arrangement 110 of the module 100. The control mechanism arrangement 810 is for controlling an operation characteristic of the one or more HRs 115.
In other words, the acoustic control system 8000 is an "active acoustic control system" or a "controllable acoustic control system", by virtue of provision of the control mechanism arrangement 810. Advantageously, the control mechanism arrangement 810 may facilitate a level of tuning or adjustability of operation characteristics of HRs.
The control mechanism arrangement 810 being provided in communication with the HR portion arrangement 110 may mean that the operation characteristic of the HRs is thereby controllable. Furthermore, being provided in communication may mean that the control mechanism arrangement 810 is configured to, or is able to, function or operate so as to control the operation characteristic. Being provided in communication may mean that the control mechanism arrangement 810 is located relative to the HR portion arrangement 110 (e.g., within or partially within a HR portion, or housed or encapsulated within one or more HRs) such that the operation characteristic is controllable. In a preferred embodiment, components of the control mechanism arrangement 810 are distributed between the HRs, and are housed or encapsulated therein, and operable to control an (e.g., at least one, but possibly multiple) operation characteristic of the HRs.
The system 8000 is configured to control an operation characteristic of the one or more HRs 115. In an example, the operation characteristic includes the resonance frequency of one or more of the HRs, a level of attenuation provided by one or more of the HRs, and/or a level of energy dissipation provided by one or more of the HRs. In an example, said operation characteristics may be controlled by adjustment of the sizes or dimensions of HRs, or volumes of air contained therein, or by manipulation of materials.
A number of examples will be described below, with reference to Figure 8, and it will be appreciated that features of the examples may be combined.
In a first example, the control mechanism arrangement 810 comprises a component 820 arranged to occupy a volume within the cavity portion 114 and/or neck portion 116. When the closing member arrangement 200 is located to close the cavity portion 114 and neck portion 116, the component 820 occupies a volume within the (closed) cavity and/or neck. The component 820 "occupying a volume" within the cavity portion 114 and/or neck portion 116 means that the component 820 displaces a volume of air within the closed HR, when formed. In this way, the resonance frequency of the HR may be modified by the presence of the component 820. The component 820 may be adjustable so as to control the size of the volume (that is, the volume that the component 820 occupies), thereby to increase or decrease a free space volume within the cavity portion 114 and/or neck portion 116. That is, the amount of air present within the cavity portion 114 and/or neck portion 116, or that displaced by the component 820, can be controlled by adjustment of the component 820 size. The component 820 may be or comprise a container having a variable internal volume, such as a balloon or inflatable element. The internal volume of the container may be increased to displace air from the cavity portion 114 and/or neck portion 116, thereby to decrease the volume of free space therein, or may be decreased thereby to allow air into the cavity portion 114 and/or neck portion 116, thereby to increase the volume of free space therein. Advantageously, in this way, the resonance frequency of the HR is controllable, and can be adaptively controlled based on the environment. Of course, it will be appreciated that the size of the respective HR, when formed, will define a resonance frequency limit, but the control mechanism arrangement 820 will thereby provide the ability to modify the resonance frequency.
In a second example, the control mechanism arrangement 810 is in the form of an adjustable neck portion 830. The adjustable neck portion 830 may be a telescopic neck, and/or may be an adjustable neck aperture. The adjustable neck aperture may have the form of an adjustable iris, similar in structure to a camera aperture. The adjustable neck portion 830 may be provided in halves, where one half is provided in the acoustic control module 100 and the other half is provided in the closing member arrangement 200. Advantageously, the adjustable neck portion 830 also provides for a level of adjustability, or tuning, of the target frequency of the HR.
In a third example, the control mechanism arrangement 810 comprises a communication arrangement 840 between two or more HRs. The communication arrangement 840 may be referred to as a controllable conduit arrangement 840. The controllable conduit arrangement 840 is selectively operable to provide a fluid flow path between two or more Helmholtz resonators, thereby to control the operation characteristic. The controllable conduit arrangement 840 may comprise one or more conduits between HRs. The controllable conduit arrangement 840 is selectively operable to enable communication between the HRs, thereby to control the operation characteristic. The controllable conduit arrangement 840 may comprise a valve, or other member which is selectively openable and closable to allow or prevent communication (and thereby provide a fluid flow path, and in an example allow or prevent airflow) between HRs. Advantageously, in this way, a greater number of possible target resonance frequencies are controllable using the system 8000. That is, by operating the controllable conduit arrangement 840 so as to allow a fluid flow path between multiple HRs, an effective dimension of one or more HRs can be increased, thereby modifying the resonance frequency.
In a fourth example, the control mechanism arrangement 810 comprises a blocking member arrangement 850. The blocking member arrangement 850 is provided within a cavity portion 114. The blocking member arrangement 850 is selectively operable to divide the cavity portion 114 into a first region which is coupled (e.g., is in communication with, such that a fluid flow path is provided) with the neck portion 116 and a second region which is decoupled (e.g., is out of communication with, such that a fluid flow path is not provided) with, or from, the neck portion 116. In this way, the effective volume of the cavity portion 114 can be selectively reduced, thereby enabling modification of the HR resonance frequency. The blocking member arrangement 850 may take the form of an arrangement of flaps, or valves, or an adjustable aperture iris. The blocking member arrangement 850 may comprise a moveable membrane and/or a container having a variable internal volume.
In a fifth example, the control mechanism arrangement 810 comprises a fluid supply assembly (not shown). The fluid supply assembly is arranged to supply fluid into the cavity, thereby to adjust or modify the volume of air (i.e., the free space volume) in the cavity. The fluid supply assembly may comprise a pump configured to pump fluid into the cavity, thereby to reduce the free space volume, and also configured to pump fluid out of the cavity, thereby to increase the free space volume. The fluid may be liquid. The liquid may be water. Fluid may be supplied into a membrane, or container of adjustable size. In this way, the fluid may be contained, whilst displacing air within the cavity. Advantageously, in this way, resonance frequency of the HR can be modified.
As mentioned above, it will be appreciated from the present disclosure that examples of the control mechanism arrangement 810 may be combined.
Applicable to all above examples, the control mechanism arrangement 810 may further comprise a controller 860 configured to control operation (e.g., movement, adjustment) of any of the components of the control mechanism arrangement 810.
The control mechanism arrangement 810 may further comprise a sensor arrangement comprising one or more sensors 870. The one or more sensors 870 are for sensing an acoustic frequency in a region proximal to the module 100. The control mechanism arrangement 810 is arranged to control the operation characteristic based on the sensed acoustic frequency. In this way, the system 8000 is adaptive, and allows adjustment or reconfigurability of the resonance frequency, level of attenuation and/or level of energy dissipation. In an example, based on the sensing output of the one or more sensors 870, the controller 860 is configured to control operation (e.g., movement, adjustment, size, configuration) of any of the components of the control mechanism arrangement, in particular the component 820, adjustable neck portion 830, communication arrangement 840, blocking member arrangement 850, and/or fluid supply assembly.
Additionally, or alternatively, in a further example, the control mechanism arrangement 810 may be provided in communication with the integral HR 160. In an example, the control mechanism arrangement 810 may be provided only in communication with the integral HR 160. Advantageously, in this way, specific resonance frequencies can be targeted by closure of open HR portions 112 in a suitable manner with appropriate closing HR portions 112 or closing members 210, but a level of adjustability is maintained by use of the control mechanism arrangement 800 provided in communication with the integral HR 160.
Referring to Figure 9, a schematic apparatus 900 is shown. The apparatus 900 comprises the acoustic control system 8000. The apparatus 900 further comprises a noise generation component 910. In an example, the noise generating component 910 provides the closing member arrangement of the system 8000. The noise generating component 910 may be, for example, a vehicle component, an engine, a propulsion system, or may be a structure or object, such as a wall, piece of equipment or furniture, etc. The noise generating component 910 may form part of a vehicle, such as a vehicle cabin or hull.
Referring to Figure 10, an acoustic control module 100 is shown. The acoustic control module 100 may incorporate any or all of the features of the acoustic control module 100 and closing member arrangement 200 described above. The acoustic control module 100 is for an acoustic control system 8000. The module 100 comprises a Helmholtz resonator portion arrangement 110 comprising one or more Helmholtz resonator portions 112, each Helmholtz resonator portion comprising a cavity portion 114 and a neck portion 116, each Helmholtz resonator portion 112 being at least partially open, wherein the module 100 and a closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions 112 to form one or more Helmholtz resonators, wherein the Helmholtz resonator portion arrangement 110 is providable in communication with a control mechanism arrangement for controlling an operation characteristic of the one or more Helmholtz resonators.
Referring to Figure 11, a schematic kit of parts 1100 is shown. The kit of parts 1100 is for, or is for forming, an acoustic control system 8000 according to an embodiment described herein. The kit 1100 comprises at least one acoustic control module 100 according to an embodiment described herein. The kit 1100 further comprises a closing member arrangement 200. The kit 1100 further comprises a control mechanism arrangement 800. The control mechanism arrangement 800 is for controlling an operation characteristic of the one or more Helmholtz resonators.
Referring to Figure 12, a method of manufacture of an acoustic control system is shown. The method uses an acoustic control module comprising a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open. Step S1210 comprises locating the module and a closing member arrangement relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators. Step S1220 comprises providing a control mechanism arrangement in communication with the Helmholtz resonator portion arrangement of the module for controlling an operation characteristic of the one or more Helmholtz resonators.

Claims

An acoustic control system comprising:
an acoustic control module comprising a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open;

a closing member arrangement, wherein the module and the closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators; and

a control mechanism arrangement provided in communication with the Helmholtz resonator portion arrangement of the acoustic control module for controlling an operation characteristic of the one or more Helmholtz resonators.
The acoustic control system according to claim 1, wherein the closing member arrangement comprises one or more additional acoustic control modules and/or one or more closing members.
The acoustic control system according to claim 2, wherein the acoustic control module is located relative to an additional acoustic control module of the closing member arrangement, so that a Helmholtz resonator portion of the additional acoustic control module of the closing member arrangement closes the Helmholtz resonator portion of the acoustic control module.
The acoustic control system according to any one of the preceding claims, wherein the operation characteristic is:
resonance frequency;

level of attenuation; and/or

level of energy dissipation.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement comprises a component arranged to occupy a volume within the cavity portion and/or neck portion, the component being adjustable so as to control the size of the volume, thereby to increase or decrease a free space volume within the cavity portion and/or neck portion.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement is in the form of an adjustable neck portion, optionally a telescopic neck, and/or an adjustable neck aperture.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement comprises a sensor for sensing an acoustic frequency in a region proximal to the module, wherein the control mechanism arrangement is arranged to control the operation characteristic based on the sensed acoustic frequency.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement comprises a controllable conduit arrangement which is selectively operable to provide a fluid flow path between two or more Helmholtz resonators, thereby to control the operation characteristic.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement comprises a blocking member arrangement provided within the cavity portion, the blocking member arrangement being selectively operable to divide the cavity portion into a first region which is coupled with neck portion and a second region which is decoupled from the neck portion.
The acoustic control system according to claim 9, wherein the blocking member arrangement comprises:
a moveable membrane; and/or

a container having a variable internal volume.
The acoustic control system according to any one of the preceding claims, wherein the control mechanism arrangement comprises a fluid supply assembly arranged to supply fluid into the cavity, thereby to adjust the volume of air in the cavity.
An apparatus comprising:
the acoustic control system according to any one of the preceding claims; and

a noise generating component, optionally wherein the noise generating component provides the closing member arrangement.
An acoustic control module for an acoustic control system, the module comprising:
a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open,

wherein the module and a closing member arrangement are locatable relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators,

wherein the Helmholtz resonator portion arrangement is providable in communication with a control mechanism arrangement for controlling an operation characteristic of the one or more Helmholtz resonators.
A kit of parts for an acoustic control system, the kit comprising:
at least one acoustic control module according to claim 13;

a closing member arrangement; and

a control mechanism arrangement for controlling an operation characteristic of the one or more Helmholtz resonators.
A method of manufacture of an acoustic control system using an acoustic control module comprising:
a Helmholtz resonator portion arrangement comprising one or more Helmholtz resonator portions, each Helmholtz resonator portion comprising a cavity portion and a neck portion, each Helmholtz resonator portion being at least partially open,
the method comprising:
locating the module and a closing member arrangement relative to one another thereby to close one or more of the one or more Helmholtz resonator portions to form one or more Helmholtz resonators; and

providing a control mechanism arrangement in communication with the Helmholtz resonator portion arrangement of the module for controlling an operation characteristic of the one or more Helmholtz resonators.