Sound system having a sound-emitting body

Abstract

A sound system having a sound-emitting body (1) comprising a fillable, viscoelastic hollow membrane (2). To achieve an improvement in the sound quality while at the same time keeping production costs low, it is proposed that the membrane tension of the viscoelastic hollow membrane (2) can be adjusted in dependence on the sound emission behaviour due to the filling pressure such that the overpressure in the hollow membrane (2) is preferably between 0.01 and 0.5 bar; and the sound system having a structure-borne sound transducer (4) which is vibrationally connected to the sound-emitting body (1).

Description

[0001] Sound system with a sound absorber

[0002] Technical field

[0003] The invention relates to a sound system with a sound emitter.

[0004] State of the art

[0005] From GB2478807A, a sound reinforcement device with a gas-filled, hollow sound emitter is known, wherein a loudspeaker assembly is integrated into the holder of the sound emitter, which is designed as a balloon. A disadvantage of this design is that the hollow diaphragm is only indirectly exposed to sound from the loudspeaker assembly, which results in distortion and a loss of sound quality.

[0006] Description of the invention

[0007] The invention is therefore based on the objective of proposing a sound reinforcement device that enables an improvement in sound quality while simultaneously reducing manufacturing costs.

[0008] The invention solves the stated problem by the features of claim 1. According to these features, the vibration induced by the structure-borne sound transducer can be directly transmitted to the viscoelastic hollow membrane, which in turn emits the sound to the surroundings. The viscoelasticity of the membrane material allows for fine-tuning of the membrane tension depending on the sound emission characteristics, since, unlike rubber-elastic materials, the filling volume is already predetermined in the unfilled state, and an increase in pressure does not result in a significant increase in volume beyond the predetermined filling volume. Furthermore, it has been shown that particularly good sound quality can be achieved with viscoelastic membrane material and appropriate membrane tension, since the lack of rubber-like elasticity largely prevents undesirable vibration damping at the membrane.For the purposes of this invention, structure-borne sound transducers are understood to be, in particular, transducers that are membrane-free and preferably electromagnetic in design. Examples include so-called exciters. Accordingly, structure-borne sound transducers according to the invention are to be distinguished from ferroelectric loudspeakers such as piezoelectric loudspeakers. To adjust the membrane tension, a filling pressure greater than the ambient atmospheric pressure is preferably selected. In particular, an overpressure, i.e., the relative pressure measured with respect to atmospheric pressure, in the sound emitter in the range of 0.01 bar to 10 bar is suitable.

[0009] The hollow membrane can, for example, be at least part of the outer shell of a balloon or an airship. The hollow membrane can be made of a polymeric material having a modulus of elasticity of at least 1000 MPa, preferably in the range of 1000 MPa to 4000 MPa, and even more preferably in the range of 2000 to 3500 MPa. A viscoelastic material according to the invention can, for example, be a plastic such as nylon or polyester. Biaxially oriented polyethylene terephthalate (BO-PET), known, for example, under the trade name Mylar, is particularly suitable as a polyester. In a further embodiment, the viscoelastic material can be an aluminum-plastic laminate with polypropylene as the polymer. Bottle-like bodies, for example, plastic bottles such as PET bottles, can also be considered hollow membranes within the meaning of the invention.The hollow diaphragm is filled with a filling medium that does not impair sound generation or only to a negligible extent. For example, the filling medium can be a filling fluid, preferably a filling gas such as air, helium, hydrogen, or sulfur hexafluoride. In a preferred embodiment, the hollow diaphragm is filled with a CCh / air mixture with a CO2 concentration of 4 vol%. The overpressure can be selected depending on the strength of the hollow diaphragm material and the filling volume of the hollow diaphragm. Particularly with the aforementioned materials, an overpressure in the range of 0.01 bar to 0.5 bar is preferably suitable, more preferably in the range of 0.01 bar to 0.25 bar, more preferably in the range of 0.01 bar to 0.1 bar, more preferably in the range of 0.01 bar to 0.08 bar, and most preferably between 0.01 bar and 0.08 bar. For higher-strength materials for the hollow diaphragm, for example, high-strength fiber or...

[0010] Fiber composite fabrics based on polymeric, organic and / or inorganic fibers, with an E-modulus based on the fiber or fiber composite fabric of more than 4000 MPa or significantly more than 4000 MPa, the overpressure can be correspondingly higher, for example in the range of 0.5 bar and 10 bar, preferably in the range of 2.5 to 10 bar, even more preferably in the range of 5 bar to 10 bar.

[0011] For ease of use, the hollow diaphragm can also be provided with a flow-connected check valve and / or quick-release coupling for filling with fluid. Such a check valve or quick-release coupling can function as a refill valve, similar to those used in gas lighters.

[0012] To achieve the most uniform sound distribution possible across a large volume of space, it is proposed that at least two sound emitters be provided, defining a common coupling space for the structure-borne sound transducer and for vibration transmission between the transducer and the sound emitters. Due to these features, the sound system can be positioned centrally within the space to be covered, with the at least two sound emitters ensuring uniform sound propagation. The coupling space can be defined by the sound emitters in such a way that the structure-borne sound transducer located within it rests directly against the hollow diaphragms.The coupling space can be formed, for example, by a material-bonded connection, such as by gluing, between hollow membrane sections of the different sound emitters, wherein preferably at most one-third, and even more preferably at most one-twelfth, of the respective hollow membrane surface forms a wall of the coupling space. To achieve increased resistance of the glued sound emitters, a circumferential connecting ring can be provided between the sound emitters, which is glued to both adjacent sound emitters. The connecting ring can, for example, be a circularly bent bamboo ring. To facilitate easy repair in the event of damage to a sound emitter, the connecting ring can have a radial opening for inserting the structure-borne sound transducer into the coupling space. The surface normal of the vibration emission surface of the structure-borne sound transducer can be normal to the contact surface of the hollow membrane.

[0013] To enable repairs without significant cost or effort in the event of damage to the sound emitter, which is usually made of inexpensive materials, the structure-borne sound transducer can be housed in a protective enclosure within the coupling chamber. This allows the costly components, particularly the electronic ones, such as the structure-borne sound transducer, to be largely protected from damaging forces and weather conditions within the enclosure.

[0014] The sound quality can be further improved if the hollow diaphragm includes a contact section that runs essentially parallel to a main transmission direction defined by the structure-borne sound transducer. This prevents any change in the direction of vibration propagation within the contact section, thereby reducing unwanted noise and volume loss. The main transmission direction preferably runs essentially perpendicular to the vibration emission surface of the structure-borne sound transducer. The contact section can, for example, run tangentially to the hollow diaphragm. In one embodiment, the contact section can rest against the side surface of a protective housing.To improve the protection of the electrical components while simultaneously enhancing sound quality, it is proposed that the structure-borne sound transducer be vibrationally connected to the sound emitter via a support element that extends at least partially in the main transmission direction and is attached to the contact section of the hollow diaphragm on its outer surface. This allows the structure-borne sound transducer and other electrical components to be positioned at a distance from the sound emitter, thus protecting them from forces and weather influences. Furthermore, the support element enables reliable vibration transmission from the structure-borne sound transducer to the hollow diaphragm, with the contact section of the support element to the hollow diaphragm running parallel to the main transmission direction.The support element can, in principle, be made of a tensile-strength material, and it is initially irrelevant whether the tensile-strength material is flexible or rigid, or even self-supporting. The only essential factor is that the support element enables reliable vibration transmission between the structure-borne sound transducer and the sound emitter, regardless of whether this is achieved, for example, by applying a tensile stress to the support element, particularly due to buoyancy, or through the inherent vibration transmission capability of a rigid and tensile-strength support element, such as a fiber-reinforced plastic rod, a wooden rod, a bamboo rod, or a rod made of a lignin-rich material like elephant grass. A tensile stress induced by buoyancy in a support element made, for example, of a nylon string, can occur when helium is used as the filling medium.The sound emitter can be attached to the support element, particularly at its contact section, using a magnet as a contact piece, thus facilitating easy assembly and repair. Alternatively, a suction cup can serve as a contact piece to connect the support element and the sound emitter, especially at its contact section.

[0015] To improve sound reproduction and allow for greater flexibility in the arrangement of sound emitters relative to the support element, it is proposed that the structure-borne sound transducer have a through-hole extending in the main transmission direction, which the support element can penetrate. This divides the support element into two sections, allowing sound emitters to be positioned both upstream and downstream of the structure-borne sound transducer in the main transmission direction. Furthermore, it has been shown that sound transmission from the inner surface of the transducer's through-hole via the corresponding section of the support element is particularly advantageous and ultimately results in even more detailed sound reproduction.

[0016] Particularly stable structural conditions combined with high-quality sound generation can be achieved if the support element is tensile-resistant and essentially rigid in bending, preferably designed as a self-supporting transmission rod. This allows the support element to exhibit improved vibration behavior and increased structural integrity. The cross-section of the support element can be of any shape, for example, circular, triangular, square, or elliptical. The support element can be made, for example, of fiber-reinforced plastic and / or a suitable wood or metal material and / or be telescopically extendable.

[0017] A connection between the structure-borne sound transducer and the support element can be implemented essentially analogously to the connection options between the sound transmission element and the support element described above. Accordingly, the structure-borne sound transducer and the support element can be detachably connected via a magnetic connection, for example, using one or more magnetic contact pieces. A connection using a clamp, such as a standard alligator clip, is also possible. In the latter case, the clamping jaw can be designed to grip the free end section of a support element, such as a transmission rod, on its outer surface. In the case of hollow transmission rods, the clamping jaw can be positioned on the free end section of the rod in such a way that it is clamped in the jaw, making contact with both the inner and outer walls of the hollow rod.

[0018] Particularly favorable conditions for flexible adaptation of the device to different acoustic and visual requirements arise when the structure-borne sound transducer is vibrationally connected to a quick-change device, especially a chuck or drill chuck, for mounting the support element. This allows, for example, pre-configured combinations of sound emitters and support elements to be quickly and easily connected to a structure-borne sound transducer via the quick-change device.

[0019] It goes without saying that all connection options between the support element and the structure-borne sound transducer or between the support element and the sound emitting body can exist not only separately, but also in combination with each other.

[0020] To offer diverse application possibilities, a control unit for the structure-borne sound transducer can be provided, which includes a signal interface. This allows audio files to be transferred to the control unit, for example, via Bluetooth, Wi-Fi, or a cable connection, and then transmitted by the structure-borne sound transducer as vibrations to the sound emitter. Improved component protection can be achieved by having a protective housing with a moisture-proof opening through which the supporting element passes.

[0021] This can be achieved, for example, by a suitable sealing element that seals the opening against the support element, thus preventing splashing or rainwater from entering the protective housing from the outside. In the simplest case, the sealing element can be an elastic sealing ring inserted into the opening.

[0022] In this context, a reduction in unwanted noise can be achieved if the sealing element is designed as a vibration damper between the edge of the through-opening on the protective housing side and the support element. This allows the support element to be directly exposed to sound by the structure-borne sound transducer in the protective housing, so that, on the one hand, the protective housing itself can remain essentially vibration-free and, on the other hand, the vibration behavior of the support element is not affected.

[0023] To achieve ease of use while maintaining a robust device design, it is proposed that the control unit include a control panel for inputting control commands. This ensures the protective housing remains moisture-proof, while the control panel provides full access to the control unit's functions. Such a sealed protective housing or control panel can, for example, meet the requirements of protection class IP44, preferably a higher protection class.

[0024] Improved sound quality can be achieved by filling the sound-emitting element with sulfur hexafluoride. Due to the significantly lower speed of sound in sulfur hexafluoride compared to air, particularly low frequencies, which contribute greatly to a well-rounded sound, can be reliably reproduced via the diaphragm surface.

[0025] To stabilize the increased weight of a sound emitter filled with sulfur hexafluoride, it is proposed that the self-supporting support element be vibrationally connected to a support mount for the sound emitter. The support mount can then serve as a contact point between the support element and the sound emitter, thus enabling reliable, high-quality sound transmission.

[0026] Surprisingly, it has been shown that a wide frequency spectrum is covered and particularly good sound characteristics are achieved when the sound-emitting element is vibrationally connected to the support element via a cell-like structure surrounded by a skin that acts as an additional sound-emitting surface. The skin covers the cell-like structure on the sound-emitting side, so that even areas of the cell-like structure that are not necessarily within the area of ​​an imaginary enveloping surface due to fissures, depressions, or the like can be covered. The structure can be, in principle, a particularly polymeric cell-like structure formed by gas bubbles. The cell-like structure can be open-pored or closed-pored. Preferably, the gas bubbles are separated from each other by solid cell walls. The skin itself is preferably not rubber-elastic, but can, in principle, be essentially gas-tight.

[0027] For example, the sound emitter can be connected to the support element via a polyurethane mounting foam. Such a skin-enclosed structure, particularly this type of foam, not only ensures reliable sound transmission during simultaneous adhesive mounting between the support element and the sound emitter, but also serves as an additional sound emitter itself. In principle, it is also possible to have multiple sound emitters, some of which have a fillable hollow membrane, while others consist of a structure surrounded by a skin that acts as a sound-emitting surface. Particularly in conjunction with polymeric foams, such as the aforementioned polyurethane mounting foams, the favorable shaping possibilities allow for the creation of not only round or...Balloon-like shapes, but also elongated shapes can be foamed.

[0028] The use of a sound reinforcement device according to the invention at large events can be made possible if the sound emitter is at least part of the outer hull of an airship. Such an airship can have at least one coupling chamber for accommodating the structure-borne sound transducer and for transmitting vibrations between the structure-borne sound transducer and the outer hull of the airship. In a preferred embodiment, several coupling chambers are provided on different parts of the outer hull of the airship, with each coupling chamber being assigned one structure-borne sound transducer.

[0029] Brief description of the invention

[0030] The invention is illustrated in the drawing as an example. It shows

[0031] Fig. 1 shows a sound system according to the invention with a foil balloon as a sound emitter and a transmission rod as a support element,

[0032] Fig. 2 shows a representation corresponding to Fig. 1 of a second embodiment of a sound reinforcement device according to the invention,

[0033] Fig. 3 shows a representation corresponding to Fig. 1 of a third embodiment of a sound system according to the invention with a structure-borne sound transducer arranged between two sound emitters,

[0034] Fig. 4 shows a fourth embodiment of a sound system according to the invention with an airship as a sound emitter and a transmission rod as a support element on a smaller scale,

[0035] Fig. 5 shows a fifth embodiment of a sound system according to the invention with sound emitters arranged in pairs around a support element,

[0036] Fig. 6 shows a representation corresponding to Fig. 6 of a sixth embodiment of a sound system according to the invention, in which the sound emitters are vibrationally connected to the support element via cell-like structures,

[0037] Fig. 7 shows a seventh embodiment of a sound system according to the invention, with sound emitters arranged in pairs around a support element, which are vibrationally connected to the support element via cell-like structures and have quick couplings for filling with a fluid, and wherein the structure-borne sound transducer comprises a through-hole for the support element, and

[0038] Fig. 8 shows a representation corresponding to Fig. 7 of an eighth embodiment of a sound system according to the invention, wherein the structure-borne sound transducer is vibrationally connected on two opposite sides to a quick-change device for receiving the support element.

[0039] Ways to implement the invention

[0040] An exemplary embodiment of a sound system according to the invention is shown in Fig. 1. The sound emitter 1 is a foil balloon forming a hollow membrane 2. This membrane is made of biaxially oriented polyethylene terephthalate (BO-PET), which is known, for example, under the trade name Mylar. The hollow membrane 2, whose membrane tension is adjustable depending on the inflation pressure, is subjected to vibrations by a structure-borne sound transducer 4, which can be controlled via a control unit 3, to generate sound, and is emitted to the environment in the form of sound waves. The vibrations are transmitted from the structure-borne sound transducer 4 to the sound emitter 1 via a carrier element 5. The carrier element 5 is connected to a corresponding contact section of the sound emitter 1 via a contact piece 6. According to the illustration in Fig.In the embodiment shown in Figure 1, the main transmission direction H of the structure-borne sound transducer 4 is essentially normal to the vibration emission surface of the structure-borne sound transducer 4, wherein the contact section of the sound emitter 1 connected to the contact piece 6 is essentially tangential to the hollow diaphragm 2. In the region of the contact section of the sound emitter 1, the hollow diaphragm 2 is essentially parallel to the main transmission direction H. The contact piece can, for example, be designed as a suction cup, which can be detachably attached to the contact section of the sound emitter via a suction connection, and which can also be detachably connected to an end section of the support element 5. It is also conceivable that the contact piece is designed as a magnet.In this case, a suitable magnetizable connector can be arranged at the contact section of the sound emitter 1, while the magnet is attached to the support element 5. For improved component protection, the structure-borne sound transducer 4 and the control unit 3 can be arranged at a spatial distance from the sound emitter in a protective housing 7.

[0041] Figure 2 shows a further embodiment of a sound system according to Figure 1, with the difference that the support element 5 is connected to the sound emitter 1 or to the hollow diaphragm 2 via a contact piece 6 on the side of the sound emitter 1 facing the structure-borne sound transducer 4. The hollow diaphragm 2 runs essentially orthogonally to the main transmission direction H in the contact section.

[0042] In the embodiments shown in Figures 1 and 2, the support element 5 is a substantially rigid transmission rod. This is made, for example, of uniaxially fiber-reinforced plastic or a suitable wood or metal material. To achieve better protection of the electronic components against external interference and weather influences, the protective housing 7 can have a moisture-tight opening through which the support element 5 passes, and which is sealed, for example, with a sealing element 8. The sealing element 8 can serve as a vibration damper between the protective housing 7 and the support element 5, so that the protective housing 7 remains essentially vibration-free, or any vibration losses transmitted into the protective housing 7 are negligible.

[0043] The control unit 3 can have an operating panel 9 accessible on the outside of the protective housing 7 for inputting control commands. The operating panel 9 can, in principle, be structurally integrated with the control unit 3. In the embodiments shown in Figures 1 and 2, the operating panel 9 is connected to the control unit 3 via a signal line 10. A second signal line 11 can be provided between the control unit 3 and the structure-borne sound transducer 4.

[0044] Figure 3 shows a third embodiment in which two sound emitters 1 are provided. The sound emitters 1 define a common coupling space 12 in which the structure-borne sound transducer 4 is arranged. The structure-borne sound transducer 4 is surrounded by a protective housing 7, which protects it from impacts and weathering. In a preferred embodiment, the protective housing 7 can also contain a power supply unit 13, for example, a battery, and a control unit 3 with a signal interface, which are connected to a power line 14. In the embodiment shown, the hollow diaphragms 2 of the sound emitters 1 are filled with a gas that is heavier than air, for example, sulfur hexafluoride. Accordingly, the sound emitters 1 are held by a schematically indicated retaining element 15, in this case a retaining cord, and e.g.The device is attached to a frame or ceiling (not shown in detail). The coupling chamber 12 is formed by bonding the two hollow diaphragms 2 of the sound emitters 1 to a connecting ring 16, wherein at most one-third, preferably at most one-twelfth, of the respective hollow diaphragm surface forms a wall of the coupling chamber 12. The connecting ring 16, for example a curved bamboo ring, serves on the one hand to increase the stability of the sound system and on the other hand, a radial opening in the, in particular slotted, connecting ring 16 allows for easy insertion and removal of the protective housing 7. Thus, the sound emitters 1 can be replaced cost-effectively.

[0045] Figure 4 shows a fourth embodiment, in which the sound emitter 1 is designed as the outer shell of a radio-controlled airship. Such a sound system can be used, for example, for the acoustic accompaniment of sporting events.

[0046] Figure 5 shows a fifth embodiment in which several sound emitters 1 and a support element 5 for subjecting the sound emitters 1 to vibration are provided. For clarity, the electronic components in the protective housing 7 are not shown in detail, but correspond to those shown in Figures 1 to 4. The different dimensions of the sound emitters 1 allow both high and low tones to be generated with high sound quality. It can also be provided that hollow diaphragms 2 are arranged in pairs on the support element 5 such that the hollow diaphragms assigned to each pair are opposite each other along a connecting axis extending transversely to the longitudinal axis defined by the support element 5. Successive pairs of hollow diaphragms can be arranged offset from each other with respect to their respective connecting axes in the direction of the longitudinal axis of the support element 5.with an angular or rotational offset about the longitudinal axis of the support element 5, related to the corresponding orientation of the connecting axes. Such an angular or rotational offset can be, for example, 90° for successive pairs of hollow membranes.

[0047] According to the embodiment shown in Fig. 6, the hollow diaphragm pairs are each embedded in a cell-shaped structure 17 surrounded by a skin that acts as an additional sound-emitting surface, and are vibrationally connected via this structure to the support element 5, which is also partially embedded by the structure 17. The structure 17 surrounded by a skin is, for example, a polyurethane mounting foam. Furthermore, it is provided that the hollow diaphragms are each fluidically connected to a check valve or a quick-release coupling 18, as schematically indicated, for filling with a fluid.

[0048] It goes without saying that the protective housing 7 and its components, which are shown relatively large in Figs. 1 to 6 for the sake of clarity, are typically smaller in practice.

[0049] In the embodiments shown in Figures 7 and 8, for the sake of clarity, only the structure-borne sound transducer 4 itself is shown, not any additional electronic components connected to it and arranged in a common housing. The two pairs of hollow diaphragms shown are in turn vibrationally connected to the support element 5 via a cell-shaped structure 17, each surrounded by a skin. A key feature of the embodiment shown in Figure 7 is that the structure-borne sound transducer includes a schematically indicated through-hole 19, which is penetrated by the support element 5.

[0050] In contrast, the embodiment shown in Fig. 8 has a structure-borne sound transducer 4 which is vibrationally connected on sides opposite each other in the main transmission direction H to a quick-change device 20, for example a chuck, for receiving the support elements 5 which are separate in this case.

Claims

Patent claims 1. Sound system with a sound emitter (1) comprising a fillable, viscoelastic hollow membrane (2) whose membrane tension is adjustable depending on the sound emission behavior by means of the filling pressure so that the overpressure in the hollow membrane (2) is preferably between 0.01 and 10 bar, and with a structure-borne sound transducer (4) which is vibrationally connected to the sound emitter (1).

2. Sound system according to claim 1, characterized in that at least two sound emitter bodies (1 ) are provided, which define a common coupling space (12) for receiving the structure-borne sound transducer (4) and for vibration transmission between the structure-borne sound transducer (4) and the sound emitter bodies (1 ).

3. Sound system according to claim 1, characterized in that the hollow membrane (2) comprises a contact section which runs substantially parallel to a main transmission direction (H) defined by the structure-borne sound transducer (4).

4. Sound system according to claim 3, characterized in that the structure-borne sound transducer (4) is vibrationally connected to the sound emitter body (1) via a support element (5) extending at least section by section in the main transmission direction (H), which is attached to the contact section of the hollow membrane (2) on the outer side.

5. Sound system according to claim 4 or 5, characterized in that the structure-borne sound transducer (4) has a through-hole extending in the main transmission direction (H) which can be penetrated by the support element (5).

6. Sound system according to one of claims 1 to 5, characterized by a tensile-resistant and substantially flexurally rigid support element (5) for the sound emitter (1).

7. Sound system according to claim 6, characterized in that the structure-borne sound transducer (4) is vibrationally connected to a quick-change device (20), in particular a chuck, for receiving the support element (5).

8. Sound system according to claim 6 or 7, characterized in that the sound emitter (1) is vibrationally connected to the support element (5) via a cell-shaped structure (17) surrounded by a skin acting as an additional sound emitter surface, in particular a polymeric foam.

9. Sound system according to one of claims 1 to 8, characterized in that the hollow diaphragm (2) is fluid-connected to a check valve and / or a quick coupling (19) for filling with a fluid.

10. Sound system according to one of claims 1 to 9, characterized in that the sound emitter (1 ) is at least a part of the outer shell of an airship.

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