JP3580718B2 - Acoustic scatterer and acoustic room - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an acoustic scatterer that scatters sound waves, and an acoustic room including the same.
[0002]
[Prior art]
Conventionally, in halls, etc., to scatter sound and suppress flutter echo and sound concentration, etc., and to realize more uniform acoustic energy distribution and improve the diffusivity of the sound field, A sound scatterer is stuck on the ceiling surface. Conventionally, as such an acoustic scatterer, those having a cross section shown in FIG. 1 having a triangular shape (a mountain shape), a semicircular shape and an arc shape are used.
[0003]
[Problems to be solved by the invention]
By the way, the above-mentioned acoustic scatterer having a mountain-shaped cross section can be manufactured at low cost, but has a narrow frequency band in which good scattering is possible, and has a cross-sectional shape that is smaller than that of a semicircular or arcuate shape. Therefore, the omnidirectional scattering effect is small. In addition, an acoustic scatterer having a semicircular cross-sectional shape has a large depth, that is, a protruding portion from an inner wall surface to which the acoustic scatterer is attached becomes large, and there is a space problem. In addition, an acoustic scatterer having an arc-shaped cross section does not have a spatial problem as a semicircular acoustic scatterer, but is inferior to a semicircular acoustic scatterer in terms of sound scattering performance. .
[0004]
The present invention has been made in view of the above circumstances, and without deteriorating space efficiency, an acoustic scatterer having better sound scattering performance in a wider frequency band, and an acoustic room including the same. The purpose is to provide.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, an acoustic scatterer according to the present invention is an acoustic scatterer that scatters sound waves,
On the hypotenuse of the isosceles triangle, the base of the cross-sectional shape formed by forming a plurality of layers of a laminated structure in which the base of the isosceles triangle having a base of substantially the same length as the hypotenuse is stacked,
A cross-sectional shape formed between an arc connecting the three vertices of each isosceles triangle stacked on the uppermost layer of the base and the hypotenuse of these upper isosceles triangles. And a surface portion that reflects and scatters light, and the angle between the hypotenuse and the base of each isosceles triangle is 20 to 30 ° .
[0007]
Further, the acoustic scatterer according to claim 2 is the acoustic scatterer according to claim 1 ,
It is characterized in that the lamination structure of a plurality of stages of the isosceles triangle is at least three or more.
[0008]
The acoustic scatterer according to claim 3 is the acoustic scatterer according to claim 1 or 2 ,
When viewed from above the surface portion side, the surface portion and the base portion are formed in a circular shape,
A cross-sectional shape along the formed circular diameter line is a shape constituted by the surface portion and the base portion.
[0009]
The acoustic scatterer according to claim 4 is the acoustic scatterer according to any one of claims 1 to 3 ,
The base is formed of a light transmitting member that transmits light, and has a hollow portion in which a lighting device can be arranged,
The surface portion is formed of a light transmitting member that transmits light.
[0010]
Further, an acoustic chamber according to claim 5 includes: an acoustic scatterer according to any one of claims 1 to 4 ;
It is characterized by having an inner wall surface or a ceiling surface to which the acoustic scatterer is attached.
[0011]
In addition, the acoustic chamber according to claim 6 includes the acoustic scatterer according to claim 4 ,
An inner wall surface or a ceiling surface to which the acoustic scatterer is attached ,
A lighting device attached to the inner wall surface or the ceiling surface,
The acoustic scatterer is detachably attached to the inner wall surface or the ceiling surface, and is attached so that the lighting device is arranged in the hollow portion.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
A. First Embodiment First, FIG. 2 is a perspective view showing an acoustic scatterer 20 according to a first embodiment of the present invention, and FIG. 3 is a view taken along line III-III of FIG. As shown in FIGS. 2 and 3, the surface (upper side in FIG. 2) of the acoustic scatterer 20 has a configuration in which four arc-shaped projections are continuously arranged. This acoustic scatterer 20 is characterized by the shape of such projections, that is, the cross-sectional shape of the acoustic scatterer 20 shown in FIG. However, it is preferable to use a flame-retardant material having the highest possible rigidity. Hereinafter, the cross-sectional shape of the acoustic scatterer 20 will be described with reference to FIG.
[0013]
As shown in FIG. 4, the cross-sectional shape of the acoustic scatterer 20 is formed of a base configured by seven isosceles triangles and a surface disposed on the upper surface of the base. The base is arranged such that an isosceles triangle 30b having the same length as the hypotenuse of the isosceles triangle 30a is superimposed on the hypotenuse of the isosceles triangle 30a having the same length as the length of the back surface of the acoustic scatterer 20. Further, a structure in which an isosceles triangle 30c having the same length as the hypotenuse is superimposed on the hypotenuse of each isosceles triangle 30b, that is, a shape in which three isosceles triangles are stacked. The surface portion of the acoustic scatterer 20 that scatters sound waves is formed in an arc shape connecting the three vertices of the isosceles triangle of the uppermost layer, that is, the four isosceles triangles 30c, as described above. ing. Here, the isosceles triangle 30a has a shape in which the angle between the base and the hypotenuse is 25 °, and the isosceles triangles 30b and 30c are similar to the isosceles triangle 30a. The angle between the oblique side and the oblique side (hereinafter referred to as the obliqueness) is 25 °. In addition, in order to clarify the explanation, the base and the surface are described separately, but they may be formed individually or may be formed integrally. Often.
[0014]
Next, the reason why the cross-sectional shape of the acoustic scatterer 20 is a lamination structure of the isosceles triangle as described above will be described. First, the base isosceles triangle 30a has a base length and an inclination set so as to obtain good scattering characteristics in a specific frequency band. By laminating the isosceles triangle 30b on the isosceles triangle 30a set in this way, good scattering characteristics can be obtained only in the isosceles triangle 30a, that is, twice the frequency band as compared with the conventional mountain-shaped acoustic scatterer. You will be able to obtain. Furthermore, by laminating the isosceles triangles 30c, it becomes possible to obtain good scattering characteristics in a frequency band three times as large as that of a conventional mountain-shaped acoustic scatterer. In other words, the cross-sectional shape in which isosceles triangles are stacked as described above is because the frequency band in which good scattering characteristics can be obtained can be expanded. Here, considering actual use, the acoustic scatterer needs to be at least three octaves, and therefore it is preferable to stack at least three or more isosceles triangles at least. Further, as described above, by forming an arc-shaped surface on the lamination of the isosceles triangles, the scattering effect is made continuous, and better scattering characteristics can be obtained. Further, by making the shape of an arc, the acoustic scattering body 20 can be easily formed.
[0015]
Next, the reason why the inclination of the above-described isosceles triangles 30a, 30b, and 30c is set to 25 ° will be described. In order to determine the gradient at which good scattering characteristics can be obtained, the present applicant performs a wave acoustic simulation in the following positional relationship between a sound source, a sound receiving point, and a reflecting surface (see FIG. 5), and obtains a result. The slope was set based on the slope. The positional relationship between the sound source and the sound receiving point was set at a far distance where plane waves were incident, and the incidence angle was perpendicular incidence as shown in FIG. The length of the base of the isosceles triangle (W = 5λ) was set so that the reflection surface was specularly reflected.
[0016]
Under such conditions, the energy distribution in the 1 KHz band is calculated every 5 ° with the inclination θ = 0 to 40 °, and the distribution shown in FIGS. 6 to 14 and the standard deviation shown in FIG. Good scattering characteristics) were obtained. From these figures, it can be seen that good scattering characteristics can be obtained when θ = 20 ° or more. On the other hand, if the inclination θ is too large, the thickness of the acoustic scatterer 20 becomes large and there is a space problem similar to the conventional acoustic scatterer having a semicircular cross section. It is considered preferable to set the angle in the range, and in the present embodiment, θ is set to 25 ° as described above.
[0017]
Next, for the reasons described above, in order to investigate the scattering characteristics of the acoustic scatterer 20 whose shape has been designed, the present applicant has set up a point sound source in a rectangular parallelepiped closed space, A wave acoustic simulation experiment was performed with the body 20 placed. For comparison with a conventional acoustic scatterer, a simulation experiment was performed on a flat plate (that is, only a wall surface), an acoustic scatterer having a semicircular cross section, and an acoustic scatterer having an arc cross section under the same conditions. Was. Then, results as shown in FIG. 16 (a) flat plate, (b) semicircle, (c) circular arc, (d) continuous circular arc (acoustic scatterer according to the present embodiment) were obtained. In the figure, it is shown that the smaller the variation of the density distribution is, the better the scattering characteristics are. From the figure, it is shown that (b) a semicircle, (d) a continuous arc, (c) an arc, and (d) a flat plate. It can be seen that good scattering characteristics can be obtained. In other words, the best scattering characteristics can be obtained when the cross-sectional shape is a semicircle, but there is a space problem as described above. As is clear from the figure, the acoustic scatterer 20 of the present embodiment has a projection height L from the flat plate that is almost the same as the acoustic scatterer having an arc-shaped cross section, but is higher than the acoustic scatterer having an arc-shaped cross section. It has excellent scattering properties.
[0018]
FIG. 16 shows the acoustic energy distribution in the sound field at the temporary point, but this energy distribution changes over time. Accordingly, the present applicant has set the time of the standard deviation (see FIG. 16) of the energy distribution described above for a flat plate, a semicircular cross section, an arc cross section, a chevron, and a continuous arc (the acoustic scatterer 20 according to the present embodiment). The changes shown in FIGS. 17 to 21 were obtained. In the case of the flat plate shown in FIG. 17, the value of the standard deviation is large irrespective of time, and there is a large periodic fluctuation. In the acoustic scatterer having a semicircular cross section shown in FIG. 18, the value of the standard deviation is small and stable, and it is considered that good scattering characteristics are obtained. Even with the acoustic scatterer having an arc-shaped cross section shown in FIG. 19, a stable standard deviation value is obtained, but there is a large fluctuation around 0.07 seconds. In the mountain-shaped acoustic scatterer shown in FIG. 20, the value of the standard deviation is large irrespective of the time, and the fluctuation is also severe. In the case of the continuous-arc acoustic scatterer 20 shown in FIG. 21, the standard deviation value is small and stable as in the case of the semicircular acoustic scatterer, and good scattering characteristics are obtained.
[0019]
From the simulation results described above, it can be said that the acoustic scatterer 20 according to the present embodiment has better scattering characteristics than an acoustic scatterer having an arc-shaped or mountain-shaped cross section. Also, there is no space problem as in the case of an acoustic scatterer having a semicircular cross section. Therefore, in the acoustic scatterer 20 according to the present embodiment, it is possible to solve a space problem while maintaining good scattering characteristics closer to an acoustic scatterer having a semicircular cross section.
[0020]
Next, a case where the above-described acoustic scatterer 20 is attached to an acoustic room will be described. Here, the acoustic scatterer 20 has a width of 900 mm, which is often used as a building panel. When an acoustic scatterer having a width of 900 mm is used as described above, a scattering characteristic of about 4 octaves centered at about 500 Hz is provided. In the case where the acoustic scatterer 20 is attached to the acoustic room, as shown in FIG. 22, a method of fixing the side flat surface of the side surface of the acoustic scatterer 20 to the inner wall surface 220 (or the ceiling surface) of the acoustic room with the flat head bolt 221. There is. As shown in FIG. 23, a plurality of acoustic scatterers 20 are sequentially attached by such an attachment method, thereby completing an acoustic chamber in which the acoustic scatterers 20 are attached to the entire inner wall surface 220. The flat plate portion 20a serving as a clearance between the acoustic scatterers 20 contributes to the improvement of the overall scattering characteristics in the sense that scattering from the adjacent arc-shaped surface portion is not hindered.
[0021]
Further, as shown in FIG. 24, the acoustic scatterer 20 may be divided into two to form divided panels 241 each of which may be combined according to the dimensions of the acoustic room. In this case, as shown in the drawing, the tab 240 is provided on the joint surface of the divided panel 241 with the other divided panel 241, and a concave portion is provided on the joint surface of the other divided panel 241. 241 may be combined.
[0022]
Note that the acoustic scatterers 20 are not arranged in the same direction in the acoustic chamber as shown in FIG. 23, and the longitudinal direction of the arc-shaped protrusions of the adjacent acoustic scatterers 20 is changed as shown in FIG. The acoustic scatterers 20 may be arranged to be orthogonal. With this arrangement, good scattering characteristics can be obtained in the horizontal direction (XZ plane in the figure), and good scattering characteristics can be obtained in the vertical direction (ZY plane in the figure).
[0023]
In addition, as shown in FIG. 26, the acoustic scatterer 20 may be attached as a pillar to the inner wall surface 40 of the acoustic room. In this case, the vertically long acoustic scatterer 20 may be integrally formed, or a plurality of the divided panels of the above-described acoustic scatterer 20 may be connected to form a pillar.
[0024]
FIGS. 27 and 28 show examples of attaching an acoustic scatterer to a ceiling surface. In the example shown in FIG. 27, the acoustic scatterers 20 are attached to the ceiling surface 41 at appropriate intervals. This is suitable for an arrangement in a large room of about 10 to 20 tatami mats, and good scattering characteristics can be obtained by attaching in this manner. On the other hand, in a case where the panel is installed in a room of 10 tatami mats or less, a sufficient scattering effect can be obtained by attaching the above-described divided panel 241 to the end of the ceiling surface 41 as shown in FIG.
[0025]
B. Second Embodiment Next, an acoustic scatterer according to a second embodiment of the present invention will be described. As shown in FIG. 29, the acoustic scatterer 50 according to the second embodiment is formed in a circular shape when viewed from the surface side. Here, FIG. 30 is a diagram viewed along the XXX-XXX line in FIG. 29, that is, a line passing through the center O of the circular acoustic scatterer 50. As shown in the figure, the acoustic scatterer 50 has the same cross-sectional shape as the acoustic scatterer 20 of the first embodiment (see FIGS. 3 and 4). That is, the cross-sectional shape cut along the diameter line passing through the center O of the acoustic scatterer 50 always has the shape shown in FIG.
[0026]
Although the above-described acoustic scatterer 20 can improve the horizontal scattering characteristics, the acoustic scatterer 50 according to the present embodiment has a cross-sectional shape of the acoustic scatterer when viewed from any direction. Since it has the same shape as 20, the scattering characteristics in the vertical direction as well as in the horizontal direction can be improved. Therefore, as shown in FIG. 31, when the acoustic scatterer 50 is attached to the inner wall surface 55 in the acoustic room, good scattering characteristics can be obtained not only in the ZX plane but also in the ZY plane direction.
[0027]
In addition, as a modified example of the above-described circular acoustic scatterer 50, an acoustic scatterer 60 as shown in FIG. 32 may be attached to a ceiling surface 62 of an acoustic room. As shown in the figure, the external shape of the acoustic scatterer 60 is exactly the same as that of the acoustic scatterer 50, but differs in that a hollow portion 61 is formed therein. The acoustic scatterer 60 is made of a translucent material that transmits light.
[0028]
An illumination device 63 attached to a ceiling surface 62 is arranged in a hollow portion 61 formed in the acoustic scatterer 60, and the light emitted by the illumination device 63 emits an acoustic scatterer 60 made of a translucent material. The sound room can be illuminated brightly through the sound room. Therefore, the acoustic scatterer 60 is a sound scatterer having excellent scattering characteristics and has a function as a lighting cover. In this case, if the acoustic scatterer 60 is detachably attached to the ceiling surface 62 such as by screwing or hooking using a hook, maintenance, replacement, cleaning, and the like of the lighting device 63 are facilitated.
[0029]
【The invention's effect】
As described above, according to the present invention, it is possible to obtain better sound scattering characteristics in a wider frequency band without deteriorating the space efficiency. The diffusivity of the field can be improved.
[Brief description of the drawings]
FIG. 1 is a perspective view showing the appearance of a conventional acoustic scatterer.
FIG. 2 is a perspective view showing an acoustic scatterer according to the first embodiment of the present invention.
FIG. 3 is a view taken along line III-III in FIG. 2;
FIG. 4 is a diagram for explaining a cross-sectional shape of the acoustic scatterer according to the first embodiment.
FIG. 5 is a diagram illustrating a slope of an isosceles triangle forming the cross-sectional shape of the acoustic scatterer, and a wave acoustic simulation for examining a sound scattering characteristic based on the slope.
FIG. 6 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 0 °.
FIG. 7 is a diagram showing an energy distribution calculated by the simulation when the slope of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 5 °.
FIG. 8 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 10 °.
FIG. 9 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 15 °.
FIG. 10 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle forming the cross-sectional shape of the acoustic scatterer is set to 20 °.
FIG. 11 is a diagram showing an energy distribution calculated by the simulation when the slope of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 25 °.
FIG. 12 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle forming the cross-sectional shape of the acoustic scatterer is set to 30 °.
FIG. 13 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle constituting the cross-sectional shape of the acoustic scatterer is set to 35 °.
FIG. 14 is a diagram showing an energy distribution calculated by the simulation when the inclination of the isosceles triangle forming the cross-sectional shape of the acoustic scatterer is set to 40 °.
FIG. 15 is a diagram showing a standard deviation of sound scattering characteristics measured by the simulation.
FIG. 16 is a diagram showing a sound scattering characteristic of a conventional acoustic scatterer measured by simulation and a sound scattering characteristic of the acoustic scatterer according to the first embodiment.
FIG. 17 is a diagram showing a relationship between a standard deviation of acoustic energy distribution in a rectangular parallelepiped on which a conventional flat plate acoustic scatterer is arranged, and time.
FIG. 18 is a diagram showing a relationship between time and a standard deviation of acoustic energy distribution in a rectangular parallelepiped in which a conventional semicircular sound scatterer is arranged.
FIG. 19 is a diagram showing a relationship between a standard deviation of acoustic energy distribution in a rectangular parallelepiped in which a conventional circular arc-shaped acoustic scatterer is arranged and time.
FIG. 20 is a diagram showing a relationship between a standard deviation of acoustic energy distribution in a rectangular parallelepiped in which a conventional mountain-shaped acoustic scatterer is arranged, and time.
FIG. 21 is a diagram illustrating a relationship between a standard deviation of acoustic energy distribution in a rectangular parallelepiped in which the acoustic scatterer according to the first embodiment is arranged and time.
FIG. 22 is a diagram for explaining a method of attaching the acoustic scatterer to the acoustic room according to the first embodiment.
FIG. 23 is a perspective view showing an acoustic room to which the acoustic scatterer according to the first embodiment is attached.
FIG. 24 is a diagram for explaining another method for attaching the acoustic scatterer according to the first embodiment to an acoustic room.
FIG. 25 is a perspective view showing another example of the acoustic room to which the acoustic scatterer according to the first embodiment is attached. FIG. 26 is a perspective view of the acoustic room to which the acoustic scatterer according to the first embodiment is attached. It is a perspective view showing other examples.
FIG. 27 is a perspective view showing a mounting example suitable for mounting the acoustic scatterer according to the first embodiment in a large room. FIG. 28 is mounting the acoustic scatterer according to the first embodiment in a small room. It is a perspective view showing the example of attachment suitable for the case.
FIG. 29 is a front view showing an acoustic scatterer according to a second embodiment of the present invention.
FIG. 30 is a view taken along line XXX-XXX in FIG. 29.
FIG. 31 is a perspective view showing an acoustic room to which an acoustic scatterer according to the second embodiment is attached.
FIG. 32 is a side sectional view showing a modified example of the acoustic scatterer according to the second embodiment.
[Explanation of symbols]
20 ... Acoustic scatterer, 30a, 30b, 30c ... Isosceles triangle, 40 ... Inner wall surface, 41 ... Ceiling surface, 50 ... Acoustic scatterer, 55 ... Inner wall surface, 60 ... Acoustic scatterer 61 hollow part, 62 ceiling surface, 63 lighting device

Claims (6)

An acoustic scatterer that scatters sound waves,
On the hypotenuse of the isosceles triangle, the base of the cross-sectional shape formed by forming a plurality of layers of a laminated structure in which the base of the isosceles triangle having a base of substantially the same length as the hypotenuse is stacked,
A cross-sectional shape formed between an arc connecting the three vertices of each isosceles triangle stacked on the uppermost layer of the base and the hypotenuse of these upper isosceles triangles. ; and a surface portion for scattering by reflecting,
The acoustic scatterer wherein the angle between the hypotenuse and the base of each isosceles triangle is 20 to 30 [deg .]. 2. The acoustic scatterer according to claim 1 , wherein the plurality of isosceles triangular stacked structures have at least three or more stacked structures. 3. When viewed from above the surface portion side, the surface portion and the base portion are formed in a circular shape,
Sectional shape along the formed circular diameter lines, acoustic scatterers according to claim 1 or 2, characterized in that a shape composed of said said surface portion base. The base is formed of a light transmitting member that transmits light, and has a hollow portion in which a lighting device can be arranged,
Acoustic scatterers according to any one of claims 1 to 3 wherein the surface portion is characterized in that it is formed of a light transmitting member which transmits light. An acoustic scatterer according to any one of claims 1 to 4 ,
An acoustic room comprising an inner wall surface or a ceiling surface to which the acoustic scatterer is attached. An acoustic scatterer according to claim 4 ,
An inner wall surface or a ceiling surface to which the acoustic scatterer is attached ,
A lighting device attached to the inner wall surface or the ceiling surface,
The acoustic room, wherein the acoustic scatterer is detachably attached to the inner wall surface or the ceiling surface, and is mounted such that the lighting device is disposed in the hollow portion.

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