The present disclosure relates to a speaker and a musical instrument case.
Examples of speakers include an actuator-driven speaker including an actuator that vibrates a flat diaphragm; and a dynamic speaker including a conical diaphragm. In the case of the actuator-driven speaker, the diaphragm is often used a highly-rigid and heavy body. Thus, there is a problem of difficulty in ensuring sound pressure across a usable band from a low frequency range to a high frequency range, including difficulty in ensuring the sound pressure particularly in a low tone range. On the other hand, in the dynamic speaker, a large-diameter speaker unit is necessary for a high-volume output, making the thickness of the speaker large. Thus, there is a problem that the dynamic speaker is not suitable for a product that requires transportability and portability. An example of a speaker that reinforces a low tone range includes a bass reflex speaker with a phase inversion enclosure (for example, see Japanese Patent Laid-Open No. 2008-48176).
A bass reflex port and an enclosure are necessary in the bass reflex speaker, and thus, the bass reflex speaker is not suitable for a product that needs to make a high output and that requires transportability and portability.
The present disclosure has been made in view of the problem, and it is desirable to provide a speaker that can ensure sound pressure across a usable band from a low frequency range to a high frequency range without affecting transportability and portability even when a high-volume output is necessary.
To solve the problem, the present disclosure provides a speaker including a first flat diaphragm; an actuator that applies vibration corresponding to a sound signal to the first flat diaphragm; and a second flat diaphragm separated from the first flat diaphragm and vibrated by the actuator.
In the speaker in a more preferable mode, an area of the first flat diaphragm is smaller than an area of the second flat diaphragm.
The speaker in a more preferable mode further includes an elastic body that connects the actuator and the second flat diaphragm.
In the speaker in a more preferable mode, the elastic body and the second flat diaphragm are integrally molded.
In the speaker in a more preferable mode, the first flat diaphragm and the second flat diaphragm are arranged to face each other.
In the speaker in a more preferable mode, the first flat diaphragm and the second flat diaphragm are arranged parallel to each other.
In the speaker in a more preferable mode, the first flat diaphragm and the second flat diaphragm are arranged on the same plane.
The speaker in a more preferable mode further includes an elastic member arranged between the first flat diaphragm and the actuator, in which the actuator applies the vibration to the first flat diaphragm through the elastic member.
In the speaker in a more preferable mode, the actuator applies, to the second flat diaphragm, vibration in a phase opposite of that of the vibration applied from the actuator to the first flat diaphragm.
In the speaker in a more preferable mode, the actuator has a shape including a first surface and a second surface, the first flat diaphragm is connected to the first surface of the actuator, and the second flat diaphragm is connected to the second surface of the actuator.
In the speaker in a more preferable mode, the elastic member is directly connected to the first surface of the actuator.
In the speaker in a more preferable mode, the elastic body is directly connected to the second surface of the actuator.
In the speaker in a more preferable mode, the second surface of the actuator is directly connected to the second flat diaphragm.
Furthermore, to solve the problem, the present disclosure provides a musical instrument case including a case main body that houses a musical instrument; a lid body; and the speaker according to any one of the modes, in which the lid body provides the second flat diaphragm.
Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
The second flat diaphragm 130A includes the entire plane portion that faces the case main body 2 when the lid body 3 is closed. The second flat diaphragm 130A is made of resin, such as polystyrene, or metal, such as aluminum. The lid body 3 is bent at substantially right angles on four sides around the second flat diaphragm 130A, and the lid body 3 is formed such that tips of the parts bent at right angles when the lid body 3 is closed come into contact with the case main body 2. That is, the musical instrument case 1 of the present embodiment is characterized in that the lid body 3 provides the second flat diaphragm 130A of the speaker 10A. The first flat diaphragm 100A is also a member formed in a flat plate shape by resin, such as polystyrene, or metal, such as aluminum. The first flat diaphragm 100A is formed in a rectangular shape with an area smaller than the area of the second flat diaphragm 130A. In the speaker 10A of the present embodiment, the first flat diaphragm 100A is provided to face the second flat diaphragm 130A. As illustrated in
As illustrated in
As illustrated in
As illustrated in
Although not illustrated in detail in
One of the first surface and the second surface of the actuator 110-1 is connected to the first flat diaphragm 100A through the elastic member 120-1 made of, for example, rubber or other elastic substances. One of the surfaces of the actuator 110-2 is also connected to the first flat diaphragm 100A through the elastic member 120-2 made of, for example, rubber or other elastic substances. Hereinafter, the elastic members 120-1 and 120-2 will be referred to as an “elastic member(s) 120” when the elastic members 120-1 and 120-2 do not have to be distinguished from each other. Once the actuator 110 expands and contracts in the axial direction according to the provided sound signal, the first flat diaphragm 100A vibrates in the axial direction of the actuator 110, and a sound wave corresponding to the sound signal is emitted from both surfaces of the first flat diaphragm 100A. In the sound wave emitted from both surfaces of the first flat diaphragm 100A, the sound wave emitted from the surface on the second flat diaphragm 130A side is emitted to the outer space of the lid body 3 through the opening 132. That is, the elastic member 120 is arranged between the first flat diaphragm 100A and the actuator 110, and the actuator 110 vibrates the first flat diaphragm 100A through the elastic member 120. In addition, the elastic member 120 is directly connected to one of the surfaces of the actuator 110.
The other of the first surface and the second surface of the actuator 110 is fixed to the second member 144 by using, for example, an adhesive or other adherent substances. That is, the connection member 140A is directly connected to the other surface of the actuator 110 to connect the actuator 110 and the second flat diaphragm 130A. Thus, vibration in a phase opposite of that of the vibration applied to the first flat diaphragm 100A is applied from the actuator 110 to the connection member 140A, and the second flat diaphragm 130A vibrates in the axial direction of the actuator 110 according to the vibration. As a result, a sound wave corresponding to the sound signal provided to the actuator 110 is also emitted from the second flat diaphragm 130A toward the outer space of the lid body 3. Note that, as described above, the first flat diaphragm 100A and the second flat diaphragm 130A are arranged parallel to each other, and thus, the first flat diaphragm 100A and the second flat diaphragm 130A both vibrate in the axial direction of the actuator 110, that is, in the same direction.
In the speaker 10A, the sound wave emitted from the first flat diaphragm 100A to the outer space and the sound wave emitted from the second flat diaphragm 130A to the outer space are in opposite phases, and it seems that the sound waves cancel each other out. However, one of or both the mass of the second flat diaphragm 130A and the elasticity of the connection member 140A can be adjusted in the speaker 10A, and the sound pressure in a specific frequency band of the sound wave from the first flat diaphragm 100A can be reinforced by the sound wave from the second flat diaphragm 130A. This can ensure the sound pressure across the usable band from a low frequency range to a high frequency range. The reason is as follows.
In the speaker 10A, a first vibration system includes the first flat diaphragm 100A, the elastic members 120, and the actuators 110, and a second vibration system includes the second flat diaphragm 130A, the connection member 140A, and the actuators 110. The second vibration system is a spring-mass system in which the mass of the second flat diaphragm 130A and the elasticity of the connection member 140A are used as parameters of the vibration system, and the parameters can be adjusted to adjust the frequency response of the second vibration system. Thus, in the speaker 10A, one of or both the mass of the second flat diaphragm 130A and the elasticity of the connection member 140A can be adjusted, and the sound pressure in the specific frequency band of the sound wave from the first flat diaphragm 100A can be reinforced by the sound wave from the second flat diaphragm 130A. This can optionally realize uniform sound pressure frequency characteristics or sound pressure frequency characteristics that reinforce the specific band.
It should be noted here that the speaker 10A according to the present embodiment does not include a bass reflex port or an enclosure. Since the speaker 10A does not include a bass reflex port or an enclosure, the speaker 10A can be thin, and the transportability and the portability of the musical instrument case 1 are not lost even when the speaker 10A is provided on the lid body 3. That is, according to the speaker 10A of the present embodiment, the sound pressure across the usable band from a low frequency range to a high frequency range can be ensured without affecting the transportability and the portability even when a high-volume low tone is necessary.
Note that the advantageous effect of the speaker 10A of the present embodiment is not limited to ensuring the sound pressure across the usable band from a low frequency range to a high frequency range. For example, in a case where the played sound of the musical instrument 4 is detected by a pickup or other apparatuses and the played sound is amplified by an audio amplifier and emitted by the speaker 10A, the second vibration system can reinforce the frequency components corresponding to the body resonance of the musical instrument 4. In this way, the body resonance can be reproduced, and accurate played sound can be emitted to the speaker 10A.
Next, a speaker 10B according to a second embodiment of the present disclosure will be described. The speaker 10B is also a speaker provided on the lid body 3 of the musical instrument case 1, similarly to the speaker 10A.
First, a connection member 140B including only the first member 142 is provided in place of the connection member 140A. Secondly, the actuators 110 and the elastic members 120 are provided in the space between the first flat diaphragm 100A and the second flat diaphragm 130A. Further, thirdly, one of the first surface and the second surface of the actuator 110 is connected to the second flat diaphragm 130A, and the other is directly connected to the first flat diaphragm 100A through the elastic member 120. In the speaker 10B of the present embodiment, part of the second flat diaphragm 130A plays a role of the second member 144 of the speaker 10A. In the speaker 10B of the present embodiment, the second flat diaphragm 130A and the connection member 140B may be integrally molded.
Also in the speaker 10B of the present embodiment, the first vibration system includes the first flat diaphragm 100A, the elastic members 120, and the actuators 110, and the second vibration system includes the second flat diaphragm 130A and the actuators 110. Thus, the same advantageous effect as in the speaker 10A of the first embodiment can also be obtained in the speaker 10B of the present embodiment. Note that, also in the present embodiment, the first flat diaphragm 100A and the second flat diaphragm 130A are arranged parallel to each other, and thus, the first flat diaphragm 100A and the second flat diaphragm 130A both vibrate in the axial direction of the actuator 110, that is, in the same direction.
Next, a speaker 10C according to a third embodiment of the present disclosure will be described. The speaker 10C is also a speaker provided on the lid body 3 of the musical instrument case 1, similarly to the speaker 10A.
First, a second flat diaphragm 130B is provided in place of the second flat diaphragm 130A. The second flat diaphragm 130B is different from the second flat diaphragm 130A in that the second flat diaphragm 130B includes, in place of the plurality of openings 132, only one rectangular opening 134 corresponding to the part surrounded by the inner circumference of the first member 142. Secondly, the connection member 140A is provided on the second flat diaphragm 130B such that the second member 144 of the connection member 140A is positioned on the same plane as the second flat diaphragm 130B. Further, thirdly, the edge 150A and the first flat diaphragm 100A are provided on the opposite side of the side in contact with the second flat diaphragm 130B in the first member 142 as illustrated in
Also in the speaker 10C of the present embodiment, the first vibration system includes the first flat diaphragm 100A, the elastic members 120, and the actuators 110, and the second vibration system includes the second flat diaphragm 130B, the connection member 140A, and the actuators 110. Thus, the same advantageous effect as in the speaker 10A of the first embodiment can also be obtained in the speaker 10C of the present embodiment. Note that, also in the present embodiment, the first flat diaphragm 100A and the second flat diaphragm 130B are arranged parallel to each other, and thus, the first flat diaphragm 100A and the second flat diaphragm 130B both vibrate in the axial direction of the actuator 110, that is, in the same direction.
While the embodiments of the present disclosure have been described above, the embodiments may obviously be modified as follows. (1) Although the area of the first flat diaphragm 100A is smaller than the area of the second flat diaphragm 130A in the speaker 10A of the first embodiment, the area of the first flat diaphragm 100A may be equal to the area of the second flat diaphragm 130A. In addition, although the number of actuators 110 is two in the speakers 10A, 10B, and 10C of the embodiments, the number of actuators 110 may be one or may be three or more. Further, although the actuators 110 of the first embodiment are connected to the first flat diaphragm 100A through the elastic members 120, the actuators 110 may be directly connected to the first flat diaphragm 100A.
(2) The actuators 110 in the embodiments may be an electrodynamic type. The electrodynamic actuator includes a base portion including a magnetic circuit and the like; and a vibration portion connected to the base portion through a damper. The vibration portion is arranged on the base portion such that the vibration portion can vibrate in the axial direction. In the case of using the electrodynamic actuator to provide the speaker of the present disclosure, the base portion can be fixed to the second flat diaphragm, and the vibration portion can be fixed to the first flat diaphragm. In this case, the damper functions as an elastic member.
(3) The examples of applying the present disclosure to the speaker provided on the musical instrument case 1 have been described in the embodiments. However, the present disclosure may be applied to a speaker mounted on a portable information terminal, such as a smartphone, a tablet terminal, a portable game console, and a notebook computer. This is because it is similarly preferable that the speaker mounted on the portable information terminal be able to ensure sound pressure across the usable band from a low frequency range to a high frequency range without affecting the transportability and the portability even when a high-volume output is necessary.
In addition, the present disclosure may also be applied to a PA speaker used in such an event as a concert. This is because it is also preferable that the transportability of the PA speaker be high even when a high-volume output is necessary, and it is preferable that the PA speaker be able to ensure sound pressure across the usable band from a low frequency range to a high frequency range. In a word, it is sufficient if a speaker including a first flat diaphragm; an actuator connected to the first flat diaphragm and configured to apply vibration corresponding to a sound signal to the first flat diaphragm; a second flat diaphragm; and an elastic body that connects the actuator and the second flat diaphragm is provided.
As illustrated in
The connection member 140C includes a first member 146 provided in a cross shape and four second members 148 formed in a cuboid shape. Each of the four second members 148 is provided on each of four edges of the first member 146, and the second members 148 are fixed to the second flat diaphragm 130C so that the center of the first member 146 and the center of the first flat diaphragm 100B overlap with each other. One of the first surface and the second surface of the actuator 110 is connected to the surface of the first member 146 facing the first flat diaphragm 100B, and the other surface of the actuator 110 is connected to the first flat diaphragm 100B through the elastic member 120. Note that the shape of the first member 146 is not limited to the cross shape, and the shape may be a three-pronged shape or a six-pronged shape. When a member with a three-pronged shape is used as the first member 146, the second member 148 can be provided on each of three edges of the first member 146 to form the connection member 140C. In addition, when a member with a six-pronged shape is used as the first member 146, the second member 148 can be provided on each of six edges of the first member 146 to form the connection member 140C.
In the speaker 10D illustrated in
It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalent thereof.
Number | Date | Country | Kind |
---|---|---|---|
2019-052388 | Mar 2019 | JP | national |
This application is a continuation of U.S. Patent Application No. PCT/JP2020/003113 filed on Jan. 29, 2020, which claims priority benefit of Japanese Patent Application No. JP 2019-052388 filed in the Japan Patent Office on Mar. 20, 2019. Each of the above-referenced applications is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
---|---|---|---|
Parent | PCT/JP2020/003113 | Jan 2020 | US |
Child | 17447930 | US |