Speaker and vehicle

Abstract

To enable sound from a speaker to be easily caught even under an environment with an obstacle in front of the speaker in a vehicle.SOLUTION: A speaker 10 includes: a diaphragm 21 having a sound emission surface 21a for emitting sound to a listening space; a drive section 22 for driving the diaphragm 21 based on a sound signal indicating the sound limited to a predetermined frequency band; and an acoustic member 40 for forming at least one opening part 41. The acoustic member 40 is a plate-like lid member and is arranged to allow a space S1 constituting a Helmholtz resonator to be formed on a side of the sound emission surface 21a for emitting the sound to the listening space. The Helmholtz resonator intensifies a component in a predetermined frequency band among the frequency components of the sound from the sound emission surface 21a, so as to attenuate the component exceeding the predetermined frequency band.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a speaker and a vehicle. [Background technology]

[0002] Speakers that utilize Helmholtz resonance are known. For example, Patent Document 1 discloses a sound generating unit that generates sound by vibration of a diaphragm housed in a housing. The housing has a case body provided on the front side of the diaphragm. A space is formed between the case body and the diaphragm, and a plurality of openings are provided in the case body. The space and the openings form a Helmholtz resonator. In the unit described in Patent Document 1, the sound pressure of the fundamental frequency in the sound generated from the diaphragm is increased by the Helmholtz resonator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-70187 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, a speaker for an in-vehicle use is disposed inside a panel such as an instrument panel or a head console. Here, the speaker may be covered by a panel from the viewpoint of design or the like. In this case, the panel becomes an obstacle that prevents sound from propagating from the speaker, and high-frequency sounds from the speaker are attenuated. The unit described in Patent Document 1 cannot adequately enhance the high-frequency sounds. For this reason, the unit described in Patent Document 1 has a problem that, when used for an in-vehicle use or the like, it becomes difficult to hear the sound from the speaker.

[0005] In consideration of the above circumstances, an object of the present invention is to make it easier to hear sound from a speaker even in an environment where there is an obstacle in front of the speaker. [Means for solving the problem]

[0006] In order to solve the above problems, a speaker according to a preferred embodiment of the present invention comprises a diaphragm having a sound emitting surface that emits sound toward a listening space, a drive unit that drives the diaphragm based on an audio signal indicating sound limited to a predetermined frequency band, and an acoustic member that forms at least one opening, wherein the acoustic member is a plate-shaped cover member that is arranged so as to form a space that constitutes a Helmholtz resonator on the sound emitting surface side that emits sound toward the listening space, and the Helmholtz resonator enhances components within the predetermined frequency band among the frequency components of the sound from the sound emitting surface and attenuates components exceeding the predetermined frequency band.

[0007] A vehicle according to a preferred embodiment of the present invention includes a speaker according to any one of the above-described embodiments. [Brief description of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a schematic external appearance of a speaker according to a first embodiment. [Diagram 2] 1 is a cross-sectional view of a speaker according to a first embodiment. [Diagram 3] FIG. 1 is a conceptual diagram of a typical Helmholtz resonator. [Figure 4] 1 is a graph showing frequency characteristics of sound from a speaker. [Diagram 5] FIG. 2 is a plan view of the acoustic member according to the first embodiment. [Figure 6] 6 is a cross-sectional view taken along the line A1-A1 in FIG. 5. [Figure 7] FIG. 11 is a plan view of an acoustic member according to a second embodiment. [Figure 8] 8 is a cross-sectional view taken along the line A2-A2 in FIG. 7. [Figure 9]1 is a conceptual diagram for explaining a case where a speaker is installed in a space separated from a listening space by a barrier. [Figure 10] FIG. 2 is a diagram for explaining a case where a speaker is installed in a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 1. First embodiment A first embodiment of the present invention will be described below with reference to the drawings. Note that the dimensions and scale of each part in the drawings are appropriately different from the actual ones. The embodiment described below is a preferred specific example of the present invention. Therefore, various technically preferable limitations are applied to this embodiment. However, the scope of the present invention is not limited to these forms unless otherwise specified in the following description to the effect that the present invention is limited.

[0010] 1-1. Speaker Overview Fig. 1 is a perspective view that shows a schematic external appearance of a speaker 10 according to the first embodiment. Fig. 2 is a cross-sectional view of the speaker 10 according to the first embodiment.

[0011] In the following, for convenience of explanation, the mutually orthogonal "X-axis", "Y-axis" and "Z-axis" are appropriately used. Moreover, one direction along the X-axis is called the "X1 direction", and the direction opposite to the X1 direction is called the "X2 direction". Similarly, one direction along the Y-axis is called the "Y1 direction", and the direction opposite to the Y1 direction is called the "Y2 direction". One direction along the Z-axis is called the "Z1 direction", and the direction opposite to the Z1 direction is called the "Z2 direction". Here, the Z-axis is an axis along the vibration direction of the diaphragm 21 described later. Moreover, a view from the Z1 direction or the Z2 direction is called a "planar view".

[0012] The speaker 10 is an in-vehicle speaker disposed inside a panel such as an instrument panel or a head console of a vehicle such as an automobile. The speaker 10 is driven by an audio signal input from an external device such as an amplifier (not shown) to emit a sound based on the audio signal. The audio signal is a signal indicating a sound limited to a predetermined frequency band. The predetermined frequency band is, for example, a band generally used for audio communication, specifically, a range of 0.3 KHz to 3.4 KHz.

[0013] The use of the speaker 10 is not limited to in-vehicle use, and may be for other purposes. The speaker 10 is also suitable for installation in a space separated from a listening space by a shield.

[0014] As shown in FIGS. 1 and 2, a speaker 10 has a sound emitting unit 20, a cabinet 30, and an acoustic member 40.

[0015] As shown in FIG. 2, the sound emitting unit 20 has a diaphragm 21, a drive section 22, and a frame 23, and is a structure in which these are unitized.

[0016] The diaphragm 21 is a vibrating body made of a sheet material. The sheet material is obtained, for example, by impregnating a fiber base material with a resin material and then curing or solidifying the resin material. Examples of the resin material include acrylic resin, polyurethane, melamine resin, modified rubber resin, and phenolic resin. Examples of the fiber base material include carbon fiber, aramid fiber, glass fiber, ceramic fiber, silica fiber, metal fiber, potassium titanate fiber, zirconia fiber, polyacrylate fiber, polyphenylene sulfide fiber, vinylon fiber, rayon fiber, nylon fiber, polyester fiber, acrylic fiber, polypropylene fiber, polyethylene fiber, cotton fiber, hemp fiber, and cellulose fiber.

[0017] The diaphragm 21 has a sound emitting surface 21a that emits sound. The diaphragm 21 is disposed so as to vibrate in a direction along the Z axis, and the sound emitting surface 21a is the surface on the Z1 direction side of both sides of the diaphragm 21. The diaphragm 21 in this embodiment is cone-shaped. Therefore, the sound emitting surface 21a is the inner wall surface of the diaphragm 21. Note that the shape of the diaphragm 21 is not limited to a cone shape, and may be, for example, a dome shape, etc.

[0018] The driving unit 22 is a mechanism that drives the diaphragm 21 based on an input audio signal. The driving unit 22 has, for example, a coil fixed to the diaphragm 21 and a permanent magnet that generates a magnetic field acting on the coil. When an electric audio signal is input, the coil vibrates the diaphragm 21 due to the interaction of magnetic forces between the coil and the permanent magnet. This vibration causes sound based on the audio signal to be emitted from the sound emission surface 21a. Note that the driving unit 22 is not limited to a configuration having a coil and a permanent magnet, and may be any configuration as long as it can drive the diaphragm 21 based on an audio signal.

[0019] Frame 23 is a structure that supports diaphragm 21 and driving unit 22. Frame 23 is made of, for example, iron or a metal material or a resin material. Diaphragm 21 and driving unit 22 are appropriately fixed to frame 23 by screws, adhesive, or the like. The shape of frame 23 is not limited to the shape shown in FIG. 2 and may be any shape as long as it can support diaphragm 21 and driving unit 22.

[0020] The cabinet 30 is a box body to which the sound emitting unit 20 and the acoustic member 40 are attached. The cabinet 30 is made of, for example, a resin material or a metal material.

[0021] The cabinet 30 is generally a hollow rectangular parallelepiped having a space S0. Specifically, the cabinet 30 has side plates 31X1 and 31X2 aligned along the X-axis, side plates 31Y1 and 31Y2 aligned along the Y-axis, and a top plate 31Z1 and a bottom plate 31Z2 aligned along the Z-axis. Each of the side plates 31X1 and 31X2 is a flat plate-like member perpendicular to the X-axis. Each of the side plates 31Y1 and 31Y2 is a flat plate-like member perpendicular to the Y-axis. Each of the top plate 31Z1 and the bottom plate 31Z2 is a flat plate-like member perpendicular to the Z-axis.

[0022] Of these plates, the sound emitting unit 20 and the acoustic member 40 are attached to the top plate 31Z1. Here, the sound emitting unit 20 and the acoustic member 40 are each fixed to the top plate 31Z1 by fitting, screwing, adhesive, or the like. The sound emitting unit 20 is disposed between the top plate 31Z1 and the bottom plate 31Z2. Therefore, the sound emitting unit 20 is disposed within the space S0 of the cabinet 30. In addition, the top plate 31Z1 is provided with an opening 32 for exposing the sound emitting surface 21a of the diaphragm 21 to the external space.

[0023] The acoustic member 40 is disposed so as to form a space S1 between itself and the sound emitting surface 21a of the diaphragm 21, and is a member having an opening 41. As will be described in detail later, the acoustic member 40 of this embodiment is plate-shaped and disposed along a plane perpendicular to the Z axis.

[0024] The space S1 and the opening 41 constitute a Helmholtz resonator. The Helmholtz resonator enhances components within a predetermined frequency band of the audio signal among the frequency components of the sound from the sound emitting surface 21a, and attenuates components beyond the predetermined frequency band.

[0025] This enhancement of the sound components has the effect of reducing the volume drop within the specified frequency band, even in an environment where there is an obstacle in front of the speaker 10. In addition, this attenuation of the sound components has the effect of reducing the sound generated by harmonic distortion of the speaker 10. These effects improve the S / N ratio, making it easier to hear the sound from the speaker 10, even in an environment where there is an obstacle in front of the speaker 10.

[0026] 1-2. Function of the Helmholtz resonator 3 is a diagram conceptually showing a typical Helmholtz resonator 50. The Helmholtz resonator 50 has a container 51 and a tube 52 connected to the container 51. In the Helmholtz resonator 50, the air in the container 51 and the tube 52 constitute a vibration system in which the air in the tube 52 serves as a mass and the air in the container 51 serves as a spring. Therefore, the Helmholtz resonator 50 increases the sound pressure at the resonant frequency of this vibration system. In addition, the Helmholtz resonator 50 reduces the sound pressure in a band that is higher than the resonant frequency of this vibration system by a predetermined amount or more.

[0027] Here, when the volume inside the container 51 is V, the length of the tube 52 is l, and the cross-sectional area inside the tube 52 is s, the resonant frequency f0 of the Helmholtz resonator 50 is expressed by the following equation (1).

number

[0028] In this formula (1), c is the speed of sound in air. Also, δ is an open end correction value, and when the cross-sectional shape inside the tube 52 is circular, δ is expressed as δ≒0.8×d, where d is the diameter inside the tube 52. As can be understood from the above formula (1), the resonant frequency f0 of the Helmholtz resonator 50 can be adjusted according to the volume V, the cross-sectional area s, and the length l. Specifically, the smaller the volume V or the length l, or the larger the cross-sectional area s, the higher the resonant frequency f0.

[0029] In the speaker 10 having the above-mentioned configuration, the space S1 corresponds to the space inside the container 51 described above. The opening 41 of the acoustic member 40 corresponds to the tube 52 described above. Therefore, the length of the opening 41 along the Z axis corresponds to the length l described above. For this reason, the desired resonance frequency f0 can be adjusted according to the cross-sectional area or length of the opening 41. Also, by preparing a plurality of acoustic members 40 with different cross-sectional areas or lengths of the opening 41 and replacing the acoustic member 40 attached to the cabinet 30, the resonance frequency f0 can be selected.

[0030] Fig. 4 is a graph showing the frequency characteristics of the sound from the speaker 10. In Fig. 4, the characteristics of the speaker 10 having the acoustic member 40 are shown by a solid line, and the characteristics in the case where the acoustic member 40 is omitted from the speaker 10 are shown by a dashed line. Fig. 4 also shows the case where the frequency band of the audio signal is in the range of 0.3 KHz to 3.4 KHz.

[0031] 4, the resonant frequency f0 of the Helmholtz resonator is near the upper limit of the frequency band of the audio signal. As a result, when the acoustic member 40 is used, the components within the frequency band of the audio signal are enhanced and the components beyond the frequency band of the audio signal are attenuated, compared to when the acoustic member 40 is not used.

[0032] 4, the resonant frequency f0 is a frequency exceeding the frequency band of the audio signal, but is not limited thereto, and may be a frequency within the frequency band of the audio signal. However, from the viewpoint of easily and effectively increasing the S / N ratio, it is preferable that the resonant frequency f0 is a frequency higher than the center frequency of the frequency band of the audio signal.

[0033] Specifically, as described above, the resonant frequency f0 of the Helmholtz resonator formed by the opening 41 and the space S1 should be able to enhance components within the specified frequency band and attenuate components beyond the specified frequency band, but from the viewpoint of further improving the S / N ratio, it is preferably in the range of 1 KHz to 5 KHz, and more preferably in the range of 2 KHz to 5 KHz.

[0034] 1-3.Details of Acoustic Component 40 FIG. 5 is a plan view of the acoustic member 40 in the first embodiment. FIG. 6 is a cross-sectional view taken along the line A1-A1 in FIG. 5. As shown in FIG. 5, the acoustic member 40 has a substantially circular outer shape in a plan view. In the example shown in FIG. 5, four protrusions 42 are provided on the outer periphery of the acoustic member 40. Therefore, by making the shape of the opening 32 of the cabinet 30 described above a shape that fits into the outer periphery of the acoustic member 40, it is possible to prevent the acoustic member 40 from being displaced in the circumferential direction relative to the cabinet 30. Note that the shape, position, number, etc. of the protrusions 42 are not limited to the example shown in FIG. 5 and are arbitrary. Also, the protrusions 42 may be provided as necessary, and may be omitted.

[0035] As described above, the acoustic member 40 is plate-shaped and has an opening 41 penetrating in the thickness direction. In this embodiment, the acoustic member 40 has one opening 41. In the example shown in Fig. 5, the opening 41 of the acoustic member 40 has a circular shape including the center PC of the sound emitting surface 21a described above in a plan view. The shape of the opening 41 in a plan view is not limited to a circle, and may be, for example, a polygon such as a triangle, a rectangle, a pentagon, or a hexagon, or may be a slit shape, a star shape, an ellipse, or the like.

[0036] As shown in FIG. 6, the thickness of the acoustic member 40 includes a first portion 43 having a constant thickness and a second portion 44 that is thicker than the first portion 43.

[0037] The first portion 43 is an annular portion that runs along the outer periphery of the acoustic member 40. The first portion 43 has a constant thickness t1. In the example shown in FIG. 6, a convex portion 45 that extends along the circumferential direction of the acoustic member 40 is provided on the surface of the first portion 43 on the Z2 direction side. The convex portion 45 contacts the wall surface of the opening 32 of the cabinet 30. This prevents the acoustic member 40 from shifting in position relative to the cabinet 30. The convex portion 45 may be provided as necessary, and may be omitted.

[0038] The second portion 44 is a portion of the acoustic member 40 that is more inward than the first portion 43. The thickness of the second portion 44 changes from thickness t1 to thickness t2 as it moves from the outside to the inside in the radial direction of the acoustic member 40. In the example shown in Fig. 6, the thickness of the second portion 44 changes continuously as it moves from the outside to the inside in the radial direction of the acoustic member 40. Note that the thickness of the second portion 44 may change stepwise as it moves from the outside to the inside in the radial direction of the acoustic member 40.

[0039] An opening 41 is provided in the second portion 44. Therefore, the length l of the opening 41 is equal to the thickness t2 of the second portion 44. In the example shown in FIG. 6, the width of the opening 41 increases from the center of the opening 41 in the Z1 direction and the Z2 direction. Therefore, sound loss at the opening 41 is reduced compared to when the width of the opening 41 is constant. Note that the width of the opening 41 may be constant.

[0040] As described above, the speaker 10 includes the diaphragm 21, the driving unit 22, and the acoustic member 40. The diaphragm 21 has the sound emitting surface 21a that emits sound. The driving unit 22 drives the diaphragm 21 based on an audio signal indicating a sound limited to a predetermined frequency band. The acoustic member 40 has one opening 41, and is disposed so as to form a space S1 that constitutes a Helmholtz resonator between the sound emitting surface 21a and the one opening 41. The Helmholtz resonator enhances components within the predetermined frequency band among the frequency components of the sound from the sound emitting surface 21a, and attenuates components exceeding the predetermined frequency band.

[0041] In the above speaker 10, among the frequency components of the sound from the sound emitting surface 21a, the components within a predetermined frequency band of the audio signal are enhanced. Therefore, even in an environment where there is an obstacle in front of the speaker 10, it is possible to reduce the reduction in volume within the predetermined frequency band. In addition, among the frequency components of the sound from the sound emitting surface 21a, the components exceeding the predetermined frequency band of the audio signal are attenuated. Therefore, it is also possible to reduce the sound generated by the harmonic distortion of the speaker 10. As a result, the S / N ratio is improved, so that it is possible to make the sound from the speaker 10 easier to hear even in an environment where there is an obstacle in front of the speaker 10.

[0042] Here, the speaker 10 has a sound emitting unit 20, a cabinet 30, and a plate-shaped acoustic member 40. The sound emitting unit 20 includes a cone-shaped diaphragm 21 having a sound emitting surface 21a for emitting sound. The sound emitting unit 20 is attached to the cabinet 30 with the sound emitting surface 21a exposed to the outside space. The acoustic member 40 is attached to the cabinet 30 with one opening 41 and disposed so as to form a space S1 between the sound emitting surface 21a and the acoustic member 40, which constitutes a Helmholtz resonator.

[0043] In this manner, the diaphragm 21 of this embodiment is cone-shaped. Therefore, the acoustic member 40 can be configured using a plate-like member or the like. This eliminates the need for the acoustic member 40 to have a complex shape, and for separately preparing a member such as a spacer to ensure the required size of the space S1. In addition, the speaker 10 can be made smaller.

[0044] The acoustic member 40 of this embodiment is a plate-shaped cover member, which makes it easier to manufacture and attach the acoustic member 40 than when the acoustic member 40 has a complex shape such as a box shape.

[0045] Moreover, the thickness of the acoustic member 40 increases toward the opening 41. Therefore, the neck length l of the Helmholtz resonator can be increased by utilizing the plate thickness of the acoustic member 40. As a result, the acoustic member 40 can be easily manufactured. In addition, the thickness of the outer periphery of the acoustic member 40 used for mounting is reduced, so the configuration for mounting the acoustic member 40 is simplified.

[0046] Here, the opening 41 is a single opening that encompasses the center CP of the diaphragm 21 when viewed from the direction in which the acoustic member 40 and the diaphragm 21 overlap (Z1 direction or Z2 direction). Therefore, it is easier to make the cross-sectional area of ​​the opening 41 larger than when a plurality of openings are provided in the acoustic member 40. This has the advantage that it is easier to increase the resonance frequency f0 of the Helmholtz resonator.

[0047] 2. Second embodiment A second embodiment of the present invention will be described below. In the following example, for elements having the same actions and functions as those in the first embodiment, the reference numerals used in the description of the first embodiment will be used and detailed descriptions of each will be omitted as appropriate.

[0048] Fig. 7 is a plan view of an acoustic member 40A in the second embodiment. Fig. 8 is a cross-sectional view taken along line A2-A2 in Fig. 7. Acoustic member 40A is similar to acoustic member 40A in the first embodiment described above, except that it has multiple openings 41A instead of one opening 41 and has a different thickness.

[0049] Specifically, as shown in Fig. 7, the acoustic member 40A has a plurality of openings 41A. The plurality of openings 41A, together with the space S1 between the acoustic member 40A and the sound radiating surface 21a, constitute a Helmholtz resonator. Here, the total cross-sectional area of ​​the plurality of openings 41A corresponds to the cross-sectional area s.

[0050] In the example shown in FIG. 7, the plurality of openings 41A are regularly arranged in a staggered manner. Each opening 41A has a circular shape in plan view. The arrangement of the plurality of openings 41A may be other regular arrangements such as a matrix, or may be random. However, when the arrangement of the plurality of openings 41A is regular, the design of the acoustic member 40A is easier than when the arrangement of the plurality of openings 41A is random. The shape of each opening 41A in plan view is not limited to a circle, and may be, for example, a polygon such as a triangle, a square, a pentagon, or a hexagon, or may be a slit shape, a star shape, an ellipse, or the like. Furthermore, the number of openings 41A is not limited to the number shown in FIG. 7, and is arbitrary. The sizes of the plurality of openings 41A may be different from each other.

[0051] As shown in Fig. 8, recesses 46 and 47 are provided on the surface of acoustic member 40A on the Z2 side. This allows the volume of space S1 to be larger than when recesses 46 and 47 are omitted. Also, the length of each opening 41A along the Z axis can be reduced. Here, width W1 of recess 46 is larger than width W2 of recess 47. Also, wall 45A surrounding recess 46 prevents displacement of acoustic member 40 relative to cabinet 30, similar to protrusion 45 described above.

[0052] The second embodiment described above can also provide the same effects as the first embodiment described above. Moreover, since the acoustic member 40A of this embodiment has a plurality of openings 41A, each opening 41A can be made large enough to prevent fingers or the like from entering. This can reduce damage to the diaphragm 21 when the acoustic member 40A is installed.

[0053] 3. Application Examples FIG. 9 is a conceptual diagram for explaining a case where a speaker 10 is installed in a space S3 separated from a listening space S2 by a shield 200. The listening space S2 is a space in which a user U exists. The space S3 is a space in which the speaker 10 is installed. The shield 200 is a structure that separates the listening space S2 from the space S3. In the example shown in FIG. 9, the shield 200 is shaped to surround the space S3. Furthermore, the shield 200 is provided with a plurality of holes 201.

[0054] Here, sound from the speaker 10 is transmitted from the space S3 to the listening space S2 through each hole 201. However, there are cases where the holes 201 cannot be arranged in front of the speaker 10 due to design considerations of the shielding object 200. Even in this case, the sound pressure is adjusted by the Helmholtz resonator in the speaker 10 as described above, so that the user U can easily hear the sound from the speaker 10.

[0055] Fig. 10 is a diagram for explaining a case where the speaker 10 is installed in the vehicle 100. Fig. 10 shows a case where the speaker 10 is installed inside the instrument panel 101 of the vehicle 100. In the vehicle 100 having the speaker 10 in this manner, even if the speaker 10 is arranged inside the instrument panel 101, it is possible to make the sound from the speaker 10 easy to hear. This increases the degree of freedom in the design of the instrument panel 101, and makes it possible to provide a vehicle 100 with excellent design.

[0056] 4. Variations The present invention is not limited to the above-described embodiments, and various modifications are possible. Furthermore, the embodiments and modifications may be combined as appropriate.

[0057] 4-1. Variation 1 In the above embodiment, the acoustic member 40 or 40A is directly attached to the cabinet 30, but the present invention is not limited to this example. For example, a frame-shaped spacer may be disposed between the cabinet 30 and the acoustic member 40. In this case, the volume of the space S1 can be adjusted by the thickness or diameter of the spacer to obtain a desired resonance frequency f0.

[0058] 4-2. Variation 2 In the above embodiment, the acoustic member 40 or 40A is shaped like a plate, but is not limited to this example. For example, the acoustic member may be shaped like a tray.

[0059] 4-3. Variation 3 In the above-described embodiment, the acoustic member 40 or 40A is separate from the cabinet 30, but this is not limiting, and the acoustic member 40 or 40A may be integrated with the cabinet 30.

[0060] 5. Notes From the above-described exemplary embodiments and modifications, the following aspects, for example, can be understood.

[0061] A speaker according to a preferred embodiment (first embodiment) of the present invention comprises a diaphragm having a sound emitting surface that emits sound toward a listening space, a drive unit that drives the diaphragm based on an audio signal indicating sound limited to a predetermined frequency band, and an acoustic member that forms at least one opening, wherein the acoustic member is a plate-shaped cover member that is arranged so as to form a space that constitutes a Helmholtz resonator on the sound emitting surface side that emits sound toward the listening space, and the Helmholtz resonator enhances, among the frequency components of the sound from the sound emitting surface, components within the predetermined frequency band and attenuates components exceeding the predetermined frequency band.

[0062] According to the above aspect, among the frequency components of the sound from the sound emitting surface, the components within a predetermined frequency band of the audio signal are enhanced. Therefore, even in an environment where there is an obstacle in front of the speaker, it is possible to reduce the volume reduction within the predetermined frequency band. Furthermore, among the frequency components of the sound from the sound emitting surface, the components exceeding the predetermined frequency band of the audio signal are attenuated. Therefore, it is also possible to reduce the sound generated by the harmonic distortion of the speaker. As a result, the S / N ratio is improved, so that it is possible to make the sound from the speaker easier to hear even in an environment where there is an obstacle in front of the speaker.

[0063] Here, since the acoustic member is a plate-like cover member, the manufacture and installation of the acoustic member are easier than when the acoustic member has a complex shape such as a box shape.

[0064] In a preferred example (second embodiment) of the first embodiment, the thickness of the acoustic member increases toward the at least one opening. According to the above embodiment, the plate thickness of the acoustic member can be used to increase the neck length of the Helmholtz resonator. As a result, the acoustic member can be manufactured easily. In addition, the thickness of the outer periphery of the acoustic member used for mounting can be reduced, which simplifies the configuration for mounting the acoustic member.

[0065] In a preferred embodiment (third aspect) of the first or second aspect, the resonant frequency of the Helmholtz resonator is a frequency higher than a center frequency of the audio signal in the predetermined frequency band.

[0066] In a preferred example (fourth aspect) of the first or second aspect, a resonant frequency of the Helmholtz resonator is near an upper limit of the predetermined frequency band of the audio signal.

[0067] In a preferred embodiment (fifth aspect) of the third or fourth aspect, a resonant frequency of the Helmholtz resonator is a frequency within the predetermined frequency band of the audio signal.

[0068] In a preferred example (sixth aspect) of any of the first to fifth aspects, the at least one opening is a single opening that encompasses the center of the diaphragm when viewed from the direction in which the acoustic member and the diaphragm overlap. According to the above aspects, the cross-sectional area of ​​the opening can be made larger than when there are multiple openings. This has the advantage that it is easier to increase the resonance frequency of the Helmholtz resonator.

[0069] In a preferred example (seventh aspect) of any of the first to fifth aspects, the at least one opening is a plurality of openings. According to the above aspect, the openings can be made large enough that fingers or the like cannot be inserted. This makes it possible to reduce damage to the diaphragm when installing the acoustic member, etc.

[0070] In a preferred example (eighth aspect) of any one of the first to seventh aspects, the resonant frequency of the Helmholtz resonator is in the range of 2 KHz to 5 KHz. According to the above aspect, the S / N ratio is improved, so that the sound from the speaker becomes easier to hear.

[0071] In a preferred example (ninth aspect) of any one of the first to eighth aspects, one surface of the acoustic member is provided with a recess that defines a part of a space that constitutes the Helmholtz resonator.

[0072] A vehicle according to a preferred embodiment (tenth embodiment) of the present invention has a speaker according to any one of the above-mentioned embodiments. According to the above embodiment, even if the speaker is arranged inside a panel such as an instrument panel or a head console, the sound from the speaker can be easily heard. Therefore, a vehicle with excellent design can be provided.

[0073] In a preferred example of the tenth aspect (eleventh aspect), the speaker is installed in a space separated from the listening space by a shield. According to the above aspect, the sound from the speaker is attenuated by the shield and then heard in the listening space, so that the effect obtained by applying the present invention is remarkable. [Explanation of symbols]

[0074] 10...speaker, 20...sound emitting unit, 21...diaphragm, 21a...sound emitting surface, 22...drive section, 30...cabinet, 40...acoustic member, 40A...acoustic member, 41...opening, 41A...opening, 50...Helmholtz resonator, 100...vehicle, 101...instrument panel, 200...shield, CP...center, PC...center, S0...space, S1...space, S2...listening space, S3...space, f0...resonant frequency, t1...thickness, t2...thickness.

Claims

1. A diaphragm having a sound emitting surface that emits sound toward a listening space; A driving unit that drives the diaphragm based on an audio signal indicating an audio sound limited to a predetermined frequency band; an acoustic member defining at least one opening; The acoustic member is a plate-shaped cover member, and is arranged so as to form a space constituting a Helmholtz resonator on the sound emitting surface side that emits sound toward the listening space, The Helmholtz resonator enhances components within the predetermined frequency band of the frequency components of the sound from the sound emitting surface and attenuates components exceeding the predetermined frequency band. speaker.

2. the thickness of the acoustic member increases towards the at least one opening; 2. The loudspeaker of claim 1.

3. a resonant frequency of the Helmholtz resonator is a frequency higher than a center frequency of the audio signal in the predetermined frequency band; 3. A speaker according to claim 1 or 2.

4. a resonant frequency of the Helmholtz resonator is near an upper limit of the predetermined frequency band of the audio signal; 3. A speaker according to claim 1 or 2.

5. a resonant frequency of the Helmholtz resonator is a frequency within the predetermined frequency band of the audio signal; 5. A speaker according to claim 3 or 4.

6. The at least one opening is an opening that includes a center of the diaphragm when viewed from a direction in which the acoustic member and the diaphragm overlap. A loudspeaker according to any one of claims 1 to 5.

7. The at least one opening is a plurality of openings. A loudspeaker according to any one of claims 1 to 5.

8. The resonant frequency of the Helmholtz resonator is in the range of 2 KHz to 5 KHz. A loudspeaker according to any one of claims 1 to 7.

9. A recess is provided on one surface of the acoustic member to define a part of a space that constitutes the Helmholtz resonator.

2. The loudspeaker of claim 1.

10. A loudspeaker comprising a loudspeaker according to any one of claims 1 to 9. vehicle.

11. The speaker is installed in a space separated from the listening space by a shield.

11. The vehicle of claim 10.

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