Speaker equipment

Abstract

To provide a speaker device that reproduces high-quality sound with a new configuration that suppresses the air spring effect. The speaker device of the present invention includes a housing 1 having a speaker unit 3 attached to a baffle plate 2, the speaker unit 3 vibrating in response to an input electric signal to output a sound wave, and an opening 4 provided on the bottom surface. A predetermined amount of granules 6 placed in the opening 4 of the housing 1 parallel to the opening end 5 closes the opening 4 . Granules 6 are present in the path from the internal space of the housing 1 to the external space, and a structure is formed in which the air in the internal space of the housing 1 is acoustically connected to the external atmosphere via the granules 6. With this configuration, it is possible to provide a speaker device that suppresses the occurrence of the air spring effect and realizes high-quality sound reproduction with a low distortion rate.

Description

[Technical field]

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

[0002] 2. Description of the Related Art In conventional sound reproduction technology, speaker devices in which a dynamic speaker such as a cone speaker is mounted in a housing are widely used.

[0003] When a cone speaker vibrates in response to an input electrical signal, if the vibration of the front of the diaphragm is in positive phase, the vibration of the rear of the diaphragm is in opposite phase. In other words, the sound waves generated from the front and rear of the diaphragm are in opposite phase to each other. These opposite phase sound waves interfere with each other based on the principle of superposition, resulting in the phenomenon of cancelling each other out.

[0004] When sound is reproduced from a cone speaker unit that is not attached to a housing, the anti-phase sound generated on the back of the diaphragm, especially the low-frequency sound with a long wavelength, wraps around to the front of the diaphragm due to the diffraction phenomenon. This anti-phase sound interferes with the positive-phase sound on the front of the diaphragm, and they cancel each other out. As a result, the cone speaker unit reproduces sound with acoustic characteristics that are biased toward the high-frequency range and attenuate the low-frequency range.

[0005] As mentioned above, the anti-phase sound generated from the back of the diaphragm can impair the reproduced sound quality. To solve this problem, a sealed structure was devised that blocks the anti-phase sound from the back of the diaphragm and contains it within the housing, leading to the current sealed speaker.

[0006] Currently available sealed speakers on the market generally employ a method in which the anti-phase sound from the rear of the diaphragm is sealed within a sealed housing, and the trapped anti-phase acoustic energy is absorbed and attenuated by porous sound-absorbing material. However, as shown in Non-Patent Document 1, glass wool, a typical porous sound-absorbing material, cannot fully absorb the acoustic energy in the low frequency range of 100 Hz or less, which has a large amount of energy. Fluctuations in air pressure caused by the residual acoustic energy create an air spring effect inside the housing, which inhibits the movement of the diaphragm, which tries to vibrate faithfully in response to the input electrical signal. For this reason, closed speakers are widely recognized as having muffled sound quality and low sound pressure in the low frequency range.

[0007] For the above reasons, bass reflex speakers that reproduce high sound pressure in the low range are the mainstream of speaker devices for reproducing sound that are currently on the market. On the other hand, although sealed speakers have a structural disadvantage called the air spring effect, they have the advantage that the anti-phase sound from the back of the diaphragm is sealed inside the housing and does not propagate into the atmosphere. Therefore, unlike bass reflex speakers, they have the advantage that the positive phase sound is not interfered with by the anti-phase sound.

[0008] It is a well-known fact that high quality sound reproduction can be achieved by suppressing the air spring effect, which is a structural defect of closed-type speakers. Based on this recognition, various methods have been devised to improve the sound quality of closed-type speakers.

[0009] Patent Document 1 discloses a method of filling 70% or more of the volume of a closed speaker housing with a viscoelastic solid-gas composite. This technology is a method in which acoustic energy from the back of the diaphragm is consumed by both airflow friction resistance and viscous flow resistance, and dissipated as heat energy. Patent Document 2 discloses a method of attaching an inverted horn-shaped sound silencing device that gradually shrinks in diameter to the back of a speaker unit inside a sealed housing. This technology uses an inverted horn-shaped sound silencing device to suppress the effect of sound waves from the back of the speaker unit on the diaphragm, preventing deterioration of sound quality while also realizing a more compact housing. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2006-352647 A [Patent Document 2] Utility Model Registration No. 3228534 [Non-patent literature]

[0011] [Non-Patent Document 1] Paramount Glass Industry Co., Ltd., "Technical Data", page 136 https: / / www.pgm.co.jp / data / pdf / S001_2020_2021_5syo_web.pdf #:▲~▼:text=127%20www.pg[Accessed September 19, 2024] Summary of the Invention [Problem to be solved by the invention]

[0012] In a closed-type speaker, if the sound-absorbing material can completely absorb the out-of-phase acoustic energy that occurs behind the diaphragm, air pressure fluctuations and the air spring effect inside the housing do not occur. Without the air spring effect, the diaphragm can faithfully respond to the input electrical signal. However, currently there is no known sound absorbing material that effectively attenuates low frequency sound energy.

[0013] Because the air spring effect in closed speakers is caused by the closed structure itself, it is difficult to solve the problem in the current situation where there is no sound-absorbing material that effectively absorbs acoustic energy in the low-frequency range. The issue of the air spring effect in closed speakers requires new ideas and solutions that differ from conventional technological approaches.

[0014] The present invention has been made in consideration of the problems with the conventional technology regarding the air spring effect described above, and has an object to provide a small speaker device with a novel configuration that suppresses the occurrence of the air spring effect and reproduces high-quality sound while maintaining the advantages of a sealed speaker. [Means for solving the problem]

[0015] In order to solve the above problems, the speaker device of the present invention includes a speaker unit that vibrates in response to an input electric signal, and a small-volume housing having an opening on a bottom surface, The opening is blocked by granules, Between the open end and the installation surface, a gap is formed by an insulator, which is in acoustic communication with the outside atmosphere; the particles are present in a path extending from the internal space of the housing through the opening to the outside, The air in the internal space of the housing is acoustically connected to the outside atmosphere via the granules.

[0016] In the present invention, the opening and the particles that close the opening while acoustically communicating with it constitute a housing having a semi-sealed structure.

[0017] Due to this characteristic semi-sealed structure, the acoustic energy generated by the diaphragm acts intensively on the particles blocking the opening. The granules are an aggregate of fine solid particles with a high specific gravity, and have innumerable minute gaps and a large surface area, with the particles having the property of moving freely according to the amount of energy load.

[0018] The acoustic energy acting on the granules vibrates the fine particles, causing friction between them and generating frictional heat between the surfaces of the fine particles. The energy passes through the granules while being dissipated and attenuated, but is not completely attenuated. The low level acoustic energy that penetrates the particles is dissipated into the atmosphere from the open end and propagates into the atmosphere as sound waves with low sound pressure.

[0019] Since the acoustic energy is dissipated into the atmosphere after passing through the particles and being attenuated, the air spring effect inside the housing is suppressed, allowing the diaphragm to vibrate faithfully in response to the input electrical signal. On the other hand, the acoustic energy dissipated into the air is significantly attenuated while passing through the particles, and the sound pressure propagating into the air as a sound wave is low. Therefore, the effect of interference between the antiphase sound on the back of the diaphragm and the positive phase sound on the front is negligibly small.

[0020] The interaction between the particles, the housing with a semi-sealed structure in which the particles block the opening, and these components suppresses the air spring effect and interference of antiphase sound, resulting in high-quality reproduced sound that is faithful to the original sound and has little distortion. Effect of the Invention

[0021] According to the present invention, the occurrence of the air spring effect inside the housing is suppressed, so that a small speaker device can be provided that has high reproducibility of the original sound over the entire frequency range and acoustic performance with little distortion. [Brief description of the drawings]

[0022] [Figure 1] FIG. 1 is a perspective view of a speaker device according to a first embodiment, a second embodiment and a third embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view of the speaker device according to the first embodiment of the present invention taken along the line XX in FIG. [Diagram 3] 2 is a cross-sectional view of a speaker device according to a second embodiment of the present invention taken along the line XX in FIG. [Figure 4] 2 is a cross-sectional view of a speaker device according to a third embodiment of the present invention taken along the line XX in FIG. 1. [Diagram 5] FIG. 11 is a perspective view of a speaker device according to a fourth embodiment of the present invention. [Figure 6] 6 is a cross-sectional view of the speaker device according to the fourth embodiment of the present invention taken along the line YY of FIG. 5. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described. Note that the embodiments described below are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0024] In one embodiment of the present invention, the opening is closed by granules. The granules are in contact with the outside atmosphere through a gap between the opening end formed by the insulator and the installation surface.

[0025] This configuration maintains acoustic communication between the air inside the housing and the atmosphere.

[0026] In one embodiment of the present invention, the volume of the housing is approximately 50% or less compared to a conventional standard small sealed speaker device.

[0027] This configuration reduces the elastic effect of the air inside the housing, and acoustic energy is efficiently transmitted to the particles in phase with the vibration of the diaphragm. In conventional sealed speakers, the improvement of sound quality was proportional to the size of the housing. However, in the semi-sealed structure of the present invention, it is important to transmit the acoustic energy to the granules in the same phase as the diaphragm, and a large housing is not suitable for the semi-sealed structure because it causes a phase delay.

[0028] In one embodiment of the present invention, the inner diameter cross-sectional area of ​​the opening is within a range of 90% to 110% of the effective vibration area of ​​the diaphragm.

[0029] With this configuration, acoustic energy is propagated to the granules in phase with the diaphragm and with approximately equal strength to the vibration of the diaphragm.

[0030] In one embodiment of the present invention, the granules are aggregates having a grain structure formed by non-magnetic solid particles.

[0031] This structure creates particles that are not attracted to the magnet of the speaker unit, preventing problems with particles getting into the magnetic circuit of the speaker unit.

[0032] In one embodiment of the present invention, the material forming the granules is an aggregate of solid particles or solid pieces having a specific gravity in the range of 2.5 to 10.0 and a short diameter in the range of 100 μm to 300 μm.

[0033] With this configuration, a granular structure is formed, and the granular structure cooperates with the semi-sealed structure that blocks the opening, thereby effectively suppressing the occurrence of the air spring effect.

[0034] In one embodiment of the present invention, a supporting wire mesh and a breathable membrane that captures particles while selectively allowing air to pass through are fixed to the inner surface of the opening, and the particles are placed on the upper surface of this breathable membrane.

[0035] This configuration makes it possible to hold the granules that block the opening in a hollow state.

[0036] In one embodiment of the present invention, the granules are enclosed within a bag made of a breathable membrane and rests on top of a supporting wire mesh that is secured to the opening.

[0037] With this configuration, it is possible to easily prevent the granules from scattering, while keeping the granules blocking the opening in a hollow state.

[0038] In one embodiment of the present invention, the granules are enclosed in a porous, particle-trapping solid container that is air permeable and is tightly secured to the inner periphery of the opening.

[0039] This makes it possible to easily prevent the granules from scattering, while keeping the granules blocking the opening in a hollow state.

[0040] <Embodiment 1> A speaker device according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. In these figures, reference symbol S1 indicates the speaker device according to this embodiment.

[0041] As shown in Figures 1 and 2, the speaker device S1 comprises a housing 1, a baffle plate 2 provided on the front surface of the housing 1, a speaker unit 3 attached to the baffle plate 2, and an opening 4 provided on the bottom surface of the housing 1.

[0042] The opening 4 is provided with a lower support wire mesh 10a at a predetermined height from the opening end 5, and the outer edge of the lower support wire mesh 10a is fixed to the inner surface of the opening 4 parallel to the opening end 5.

[0043] The opening 4 further includes a lower breathable membrane 9a in contact with the upper surface of the lower support wire mesh 10a, and the outer edge of the lower breathable membrane 9a is tightly fixed to the inner peripheral surface of the opening 4.

[0044] The opening 4 further includes granules 6 placed on the upper surface of the lower breathable membrane 9a. The granules 6 are placed parallel to the opening edge with a predetermined thickness to close the opening 4.

[0045] The opening 4 further includes an upper-stage breathable membrane 9 arranged at a predetermined height from the upper surface of the granules 6, and the outer edge of the upper-stage breathable membrane 9 is tightly fixed to the inner peripheral surface of the opening 4.

[0046] The opening 4 further includes an upper support wire mesh 10 positioned at a predetermined height from the upper surface of the upper breathable membrane 9, and the outer edge of the upper support wire mesh 10 is fixed to the inner surface of the opening 4 parallel to the opening end 5.

[0047] The housing 1 is provided with an insulator 11 that maintains a predetermined spatial distance between the open end 5 and the installation surface, and the insulator 11 is either attached to the housing 1 in advance or configured as a separate body.

[0048] In the speaker device S1, a path from the internal space of the housing 1 through the open end 5 to the external space is blocked by the granules 6, but the internal space of the housing 1 is acoustically connected to the atmosphere via the granules 6.

[0049] The granules 6 blocking the openings 4 are composed of zircon sand (zirconium silicate) particles. This zircon sand has a specific gravity of 4.7, a grain size of about 150 μm, and a diameter of 1 cm. 3 The total surface area is 39.7 cm 2 The granules 6 have numerous minute gaps and a large surface area. It is also possible to use particles or solid pieces having similar properties to zircon sand instead of the zircon sand for the granules 6, to mix particles having different specific gravities and particle sizes, to place different types of particles in layers, or to place sound-absorbing material made of another material on top of the granules 6.

[0050] The operation of the speaker device S1 will be described. Due to the characteristic semi-sealed structure of the present invention, the acoustic energy inside the housing is concentrated at the opening and passes through the granules 6. The acoustic energy passes through the granules 6 while attenuating its energy, but is not attenuated completely. The low-level acoustic energy that passes through the granules 6 is dissipated into the atmosphere from the open end 5 and propagates into the atmosphere as a sound wave with low sound pressure.

[0051] Since the acoustic energy is dissipated into the atmosphere after passing through the particles 6, the occurrence of the air spring effect inside the housing is suppressed. As a result, the diaphragm vibrates faithfully in response to the input electrical signal. On the other hand, since the acoustic energy dissipated into the air after passing through the particles 6 is significantly attenuated, the sound pressure of the sound from the rear of the diaphragm propagating into the air as a sound wave is low. As a result, the effect of interference of the antiphase sound with the positive phase sound is so small that it can be practically ignored.

[0052] The speaker device S1 is capable of reproducing high-quality sound that is faithful to the original sound and has little distortion, by the cooperation of the components: the granules 6 formed by particles with characteristic properties, and the small-volume housing 1 with a semi-sealed structure.

[0053] <Embodiment 2> A speaker device S2 according to a second embodiment of the present invention will be described with reference to Fig. 1 and Fig. 3. This embodiment has the same configuration as that of the first embodiment except for the method of placing the particles 6, and the same components as those of the previous embodiment are denoted by the same reference numerals. Explanations that overlap with the first embodiment will be omitted, and differences will be mainly described.

[0054] In the second embodiment, the granules 6 are placed directly on the upper surface of the lower supporting wire mesh 10a of the opening 4 without using the breathable films 9 and 9a used in the first embodiment.

[0055] The opening 4 is provided with granules 6 enclosed in a breathable bag 7, and the bag 7 containing the granules 6 is placed parallel to the opening end 5 between a lower support wire mesh 10a and an upper support wire mesh 10 fixed to the inner surface of the opening 4, so that the granules 6 block the opening 4.

[0056] The speaker device S2 operates based on the same principle as in the embodiment 1. Specifically, the occurrence of the air spring effect is suppressed and interference with the positive phase sound is reduced by attenuating the anti-phase acoustic energy in the housing as it passes through the gaps between the particles of the granules 6. As a result, the original sound is reproduced more faithfully with a low distortion rate, and high-quality sound reproduction is realized over a wide frequency range.

[0057] <Embodiment 3> A speaker device S3 according to a third embodiment of the present invention will be described with reference to Fig. 1 and Fig. 4. This embodiment has the same configuration as that of the first embodiment except for the method of placing the particles 6, and the same components as those of the previous embodiment are denoted by the same reference numerals. Explanations that overlap with the first embodiment will be omitted, and differences will be mainly described.

[0058] In the third embodiment, the granules 6 are contained in a container 8 and placed directly on the opening 4 without using a breathable membrane or a supporting wire mesh.

[0059] The opening 4 is provided with granules 6 enclosed in a container 8 formed of an air-permeable porous solid, and the container 8 enclosing the granules 6 is tightly fixed to the inner peripheral surface of the opening 4, with the granules 6 blocking the opening 4.

[0060] The speaker device S3 operates based on the same principle as in the embodiment 1. Specifically, the occurrence of the air spring effect is suppressed and interference with the positive phase sound is reduced by attenuating the anti-phase acoustic energy in the housing as it passes through the gaps between the particles of the granules 6. As a result, the original sound is reproduced more faithfully with low distortion, and high-quality sound reproduction is realized over a wide frequency range.

[0061] <Embodiment 4> A speaker device S4 according to a fourth embodiment of the present invention will be described with reference to Fig. 5 and Fig. 6. The speaker device S4 of the fourth embodiment differs from the third embodiment in that it has a cylindrical housing 1 and a baffle plate 2 arranged on the upper surface of the housing 1, but the other structures are similar to those of the third embodiment. Components common to the previous embodiments are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0062] As shown in Figures 5 and 6, the speaker device S4 comprises a cylindrical housing 1, a baffle plate 2 provided on the upper surface of the housing 1, a speaker unit 3 attached to the baffle plate 2, and an opening 4 provided on the bottom surface of the housing 1.

[0063] As in embodiment 3, the opening 4 is blocked by granules 6 enclosed in a container 8 made of an air-permeable porous solid, and the outer edge of the container 8 is tightly fixed to the inner surface of the opening 4 in parallel with the opening end 5. The method of placing the granules 6 that close the opening 4 may be either the method using the supporting wire meshes 10, 10a and the breathable films 9, 9a in the first embodiment, or the method using the bag body 7 in the second embodiment.

[0064] As shown in FIG. 6, the outer diameter of the cylindrical housing 1 is close to the outer diameter of the speaker unit 3, which makes it possible to effectively reduce the volume of the housing 1.

[0065] The particles 6 that close the opening 4 and the diaphragm are arranged facing each other with an approximate area of ​​90% to 110% of each other. This configuration, in cooperation with the housing with a smaller volume, allows the acoustic energy from the back side of the diaphragm to be transmitted more effectively to the particles 6 in phase with the diaphragm.

[0066] The speaker device S4 operates based on the same principle as in the first embodiment. Specifically, the anti-phase acoustic energy in the housing is attenuated in the process of passing through gaps between the particles of the granules 6, thereby suppressing the occurrence of the air spring effect and reducing interference with the positive phase sound. As a result, the original sound is reproduced more faithfully with a low distortion rate, and high-quality sound reproduction is realized over a wide frequency range. [Explanation of symbols]

[0067] 1 Case 2 Baffle plate 3 Speaker unit 4 Openings 5 Open End 6 grains 7 Bag body 8 containers 9 Upper breathable membrane 9a Lower breathable membrane 10 Upper support wire mesh 10a Lower support wire mesh 11 Insulator

Claims

1. An independent, stationary speaker device, A housing with a speaker unit attached to a baffle board on the front or top, which vibrates in response to an input electrical signal and outputs sound waves; an opening provided on a bottom surface of the housing and having an area substantially equal to a vibration area of ​​a diaphragm of the speaker unit; and a granule made of fine solid particles placed so as to close the opening, The speaker device is characterized in that a path from an internal space of the housing to an external space is acoustically connected, and the particles are present in the path.

2. A speaker device as described in claim 1, characterized in that an insulator provided between the opening and the installation surface forms a predetermined gap for acoustically connecting the internal space of the housing with the external atmosphere.

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