JP3062378B2 - Sound absorbing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sound absorbing device which provides an ideal sound space by combining a plurality of sound members.

[0002]

2. Description of the Related Art In recent years, it has been often practiced to optimally arrange acoustic members such as a sound absorbing material and a reflective sound insulating material in a room to realize an ideal sound reproducing space. 2. Description of the Related Art A sound absorbing device is used in a listening room or the like for reproducing music in order to adjust the sound.
Examples of the sound absorbing material used in the sound absorbing device include glass wool and rock wool, and a porous sound absorbing material made of a foamed polymer. A conventional sound absorbing device using such a sound absorbing material will be described with reference to FIG.

FIG. 5 is an external view of a sound absorbing device 1 used in a sound reproducing space. The sound absorbing device 1 is configured by arranging a large number of sound absorbing bodies 2 and reflection cabinets 3 in a mosaic shape.
The sound absorber 2 is a basic block made of the above-described porous sound absorbing material formed into a rectangular shape. The reflection cabinet 3 has a baffle plate having a quadrangular pyramid projection on a baffle surface as a basic block. The outer shape of each basic block is set so as to have the same shape or similar shape. Then, the wall surface is configured by combining the sound absorbing body 2 and the reflecting cabinet 3 so as to obtain a target reverberation characteristic. Thus, a sound reproduction space such as a listening room is realized.

[0004]

In such a conventional sound absorbing device, the frequency of the sound that is absorbed or reflected and diffused depends on the material such as glass wool and rock wool, and the thickness of a porous acoustic sound absorbing material made of a foamed polymer. Limited by unique characteristics.
On the other hand, when the sound absorbing device 1 is used as a partition, the thickness of its wall is about 8 to 15 cm. In this case, the thickness of the sound absorber 2 is about 5 to 10 cm. With such a thickness of the sound absorbing body 2, the frequency characteristic of the sound that the porous sound absorbing material absorbs increases as shown in FIG. 6 at higher frequencies, but decreases at lower frequencies. For this reason, the frequency characteristics of the reverberation time are not flat, and the reverberation time is long in a low band and short in a high band. As described above, since low-frequency sound is not absorbed and diffused, sufficient reverberation characteristics cannot be obtained, and there has been a problem that standing waves and echo disturbances cannot be removed.

SUMMARY OF THE INVENTION The present invention has been made in view of such conventional problems, and has excellent reverberation characteristics by absorbing and diffusing sound from lower frequencies without increasing the thickness of a sound absorber serving as a wall. It is an object of the present invention to realize a sound absorbing device capable of realizing a sound absorbing device capable of eliminating standing waves and echo disturbances.

[0006]

According to the first aspect of the present invention, a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of a minimum reference size, and the sound absorbing material penetrates from a sound incident surface. A sound absorber provided with a through hole, a hollow pipe having one end connected to the through hole of the sound absorber, and connected to the other end of the pipe,
And a cabinet having a space formed therein.

According to the invention of claim 2 of the present application, the porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of the minimum reference dimension, and a plurality of through holes penetrating from the sound incident surface. , A hollow pipe having one end connected to the through-hole of each sound absorber, and a hollow pipe connected to the other end of the pipe so that the internal volume of the space is an integral multiple of the reference volume. And a plurality of types of cabinets.

According to a third aspect of the present invention, a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of a minimum reference dimension, and a plurality of through holes penetrating from a sound incident surface. A hollow pipe formed with a plurality of lengths such that one end is connected to each of the through holes of the respective sound absorbers, and the acoustic mass thereof is an integral multiple of a reference value. A cabinet connected to the end and having a space formed inside,
It is characterized by having.

According to the invention of claim 4 of the present application, the porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the vertical and horizontal lengths are integral multiples of the minimum reference dimension, and a plurality of through holes penetrating from the sound incident surface. A sound absorbing body, a hollow pipe having one end connected to a through hole of each sound absorbing body, and a diffuser plate attached to at least one of the upper, lower, left, and right sides of the sound absorbing body to reflect and diffuse incident sound, and A reflection cabinet connected to the other end of the pipe to form a space.

[0010]

According to the first aspect of the present invention having such a feature, when unnecessary reverberation occurs in the acoustic space, sound enters the surface of the sound absorbing body and is absorbed by the porous sound absorbing material. The sound absorption coefficient here is effective for a sound of a slightly higher frequency body due to the limitation of the thickness of the sound absorbing material, but is not sufficiently absorbed in a low frequency range. However, when sound enters the interior of the cabite through the through hole, the sound of the frequency determined by the internal volume of the cabinet is well absorbed. Since this frequency can be set lower than the absorption frequency of the sound absorbing body surface, the sound absorbing characteristics are improved in the entire frequency band as the sound absorbing device.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the cabinet is set to have several types of internal volumes, so that the area of the absorption frequency band can be expanded. Become.

According to the third aspect of the present invention, in addition to the function of the first aspect of the present invention, several types of pipes are provided so that their acoustic masses are different from each other. The region of the absorption frequency band is expanded as it is.

According to the fourth aspect of the present invention, in addition to the function of the first aspect of the present invention, since the space for the resonator is provided inside the reflection cabinet, it is not necessary to newly provide a mounting place for the cabinet. Good.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A sound absorbing device according to a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an external view showing the configuration of the sound absorbing device 10 of the first embodiment. Sound absorber 1 to be a sound absorbing wall
Reference numeral 1 denotes a porous acoustic sound absorbing material made of glass wool, rock wool, or a foamed polymer. Assuming that the reference dimension in the vertical direction of the sound absorbing body 11 is Y and the horizontal dimension is X, the horizontal dimension ratio X / Y to the vertical is set to be 1, 2,. Then, the outer shape of the sound absorbing body 11 is made substantially a rectangular parallelepiped.

Next, a plurality of through holes 12 are provided on the sound incident surface of the sound absorber 11. Each of the through holes 12 is connected to a bendable cylindrical pipe 13 having substantially the same outer diameter as the through hole 12. Further, a cabinet 14 which is hollow and sealed is connected to the other end faces of these pipes 13. In this way, a so-called Helmholtz resonator is constituted by the acoustic mass at the pipe 13 and the acoustic capacity at the cabinet 14.

A plurality of the sound absorbing bodies 11 configured as described above and the same reflecting cabinet 3 as the conventional example are combined and assembled into a sound absorbing device similar to that shown in FIG. Pipe 1
The cabinet 14 connected to the cabinet 3 does not need to be provided on a wall surface, but may be provided on the ceiling of a room serving as a sound reproduction space or on the back side of the reflective cabinet 3.

When the sound absorbing device 10 is configured as described above,
The resonance frequency of the Helmholtz resonator is determined by the acoustic mass of the pipe 13 and the acoustic capacity of the cabinet 14 in addition to the sound absorbing characteristics inherent to the porous sound absorbing material. Therefore, in order to improve sound absorption characteristics in a lower frequency band, the center frequency of the Helmholtz resonator may be set to a low frequency at which the porous sound absorbing material cannot absorb sound. If the cabinets 14 are connected by the bendable pipes 13, the cabinets 14 can be provided on portions other than the wall surface which becomes the sound incident surface, and the wall of the room does not need to be thickened.

Next, a sound absorbing device according to a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is an external view showing the configuration of the sound absorbing device 20 of the second embodiment. The sound absorbing body 21 serving as the sound absorbing wall is made of a porous acoustic sound absorbing material made of glass wool, rock wool, or a foamed polymer as in the first embodiment. As in the first embodiment, assuming that the reference dimension in the vertical direction of the sound absorbing body 21 is Y and the horizontal dimension is X, the horizontal dimension ratio X / Y to the vertical is set to 1, 2,. Then, the external shape is made into a substantially rectangular parallelepiped.

Next, a plurality of through holes 22 are provided on the sound incident surface of the sound absorbing body 21. One end of a bendable cylindrical pipe 23 having an outer diameter substantially the same as that of the through hole 22 is connected to each of the through holes 22. Further, cabinets 24a, 24b... 24 having different shapes are provided at the other ends of the plurality of pipes 23.
n. The internal volume of the smallest cabinet 24a is V
, Cabinets 24a, 24b, 24c,.
The internal volumes of 24n are 1V, 2V, 3V... NV, respectively. These volume ratios are 1, 4, 8,... 2
^N may be used. With this configuration, a plurality of sets of center frequencies of the Helmholtz resonator are set in a lower frequency band, so that low-frequency sound absorption characteristics become more flat, and reverberation characteristics independent of frequency are obtained.

A sound absorbing device according to a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is an external view showing the configuration of the sound absorbing device 30 of the third embodiment. As in the first and second embodiments, a rectangular solid sound absorber 3 made of a porous acoustic sound absorbing material
A plurality of through holes 32 are provided in one, and a plurality of cabinets 34 of the same shape are connected through a cylindrical pipe 33.

Unlike the first and second embodiments, the length of the pipe 33 is changed for each cabinet 34. Assuming that the shortest pipe is the pipe 33a, the acoustically equivalent length is one time, 2
Pipes 33a, 33b, etc., which are integral multiples
・ 33n are provided respectively. With such a sound absorbing device, the resonance frequency of Helmholtz can be made different for each cabinet 34, and the sound absorbing characteristics in a low frequency band can be improved while keeping the outer shape of the cabinet 34 the same.

A sound absorbing device 40 according to a fourth embodiment of the present invention.
Will be described. In the sound absorbing devices of the first to third embodiments, the sound absorbing body and the cabinet are separately provided. However, as shown in FIG. 4, in the sound absorbing device 40 of the present embodiment, both the reflection cabinet and the cabinet for resonance are used. I have. This sound absorbing device 4
0, a sound absorber 41 similar to that of the first to third embodiments is provided at the center, and the reflection cabinet 42
Is arranged. The inside of the reflection cabinet 42 becomes a resonance box, and the surface is formed in, for example, a quadrangular pyramid shape, and serves as a sound diffuser. Then, a through hole 43 is provided in the sound absorbing body 41, and the internal space of the reflection cabinet 42 and the sound absorbing body 41 are connected by a pipe 44. In this way, the sound absorber 41 and the reflection cabinet 42 can be installed on the same wall, and the sound absorber 40 can be configured without increasing the thickness of the wall.

[0023]

As described above, according to the first aspect of the invention, the Helmholtz resonator is constituted by the acoustic mass of the pipe and the acoustic capacity of the cabinet. By setting a low frequency that cannot be absorbed by the sound absorbing material, a sound absorbing effect can be obtained up to a lower frequency band. Further, since the sound absorbing body and the cabinet are connected via the pipe, the cabinet can be provided in a portion other than the wall surface which becomes the sound incident surface, and the thickness of the sound absorbing wall can be reduced.

According to the invention of claim 2 of the present application, in addition to the effect of the invention of claim 1, a plurality of sets are provided such that the internal volume of each cabinet connected to the pipe is an integral multiple of the reference volume. Therefore, the resonance frequency of the resonator can be made different for each cabinet. Therefore, the sound absorption characteristics can be flattened to a lower frequency band. Therefore, an acoustic space having excellent reverberation characteristics and free from standing waves and echo disturbances can be realized.

According to the invention of claim 3 of the present application, claim 1
In addition to the effect of the invention, since each pipe is formed in a plurality of lengths so that the acoustic mass is an integral multiple of the reference value,
The resonance frequency of the resonator can be set arbitrarily without changing the outer shape of the cabinet.

According to the invention of claim 4 of the present application, claim 1
In addition to the effects of the invention, since the space for the resonator is provided inside the reflection cabinet serving as the sound diffuse reflection plate, it is not necessary to newly provide a mounting place for the cabinet.
For this reason, a sound absorber having a small wall thickness can be realized.

In any of the first to sixth aspects of the present invention, since the outer shape of the sound absorber is formed to be an integral multiple of the minimum size of the sound absorber, a plurality of sound absorbers are stacked to form a sound absorbing wall. Sound absorbers having different absorption frequencies can be installed in any combination.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a sound absorbing device according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a configuration of a sound absorbing device according to a second embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating a configuration of a sound absorbing device according to a third embodiment of the present invention.

FIG. 4 is a schematic diagram illustrating a configuration of a sound absorbing device according to a fourth embodiment of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a conventional sound absorbing device.

FIG. 6 is a frequency characteristic diagram of a sound absorption coefficient of a porous sound absorbing material used for a sound absorbing device.

[Explanation of symbols]

 10, 20, 30, 40 Sound absorber 11, 21, 31, 41 Sound absorber 12, 22, 32, 43 Through hole 13, 23, 33a to 33n, 44 Pipe 14, 24a to 24n, 34 Cabinet 42 Reflective cabinet

Claims (6)

(57) [Claims] 1. A sound absorber in which a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of a minimum reference size, and a through hole is provided through a sound incident surface; And a cabinet connected to the other end of the pipe and having a space formed therein. 2. A sound absorber in which a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of a minimum reference dimension, and a plurality of through holes penetrating from a sound incident surface are provided; A hollow pipe having one end connected to the through hole of each sound absorber, and a plurality of types of cabinets connected to the other end of the pipe and formed such that the internal volume of the space is an integral multiple of a reference volume. A sound absorbing device comprising: 3. A sound absorber in which a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped such that the length and width thereof are integral multiples of a minimum reference dimension, and a plurality of through holes penetrating from a sound incident surface are provided. One end is connected to the through-hole of each of the sound absorbers, a hollow pipe formed in a plurality of lengths such that the acoustic mass thereof is an integral multiple of a reference value, and connected to the other end of the pipe, A cabinet having a space formed therein. 4. A sound absorber in which a porous acoustic sound absorbing material is formed in a substantially rectangular parallelepiped so that the length and width thereof are integral multiples of a minimum reference dimension, and a plurality of through holes penetrating from a sound incident surface are provided. A hollow pipe having one end connected to the through hole of each of the sound absorbers, a diffusion plate attached to at least one of the upper, lower, left, and right sides of the sound absorber to reflect and diffuse incident sound; and the other end of the pipe. And a reflection cabinet connected to form a space. 5. The sound absorbing device according to claim 1, wherein the sound absorbing material of the sound absorbing body is made of glass wool, rock wool, or a foamed polymer. 6. The sound absorbing device according to claim 1, wherein the pipe is a bendable cylindrical pipe.