JP6250412B2 - Method for producing porous ceramic acoustic material and acoustic structure - Google Patents

Description

  The present invention relates to a method for manufacturing a porous ceramic acoustic material used for noise countermeasures and room acoustic control, and an acoustic structure.

  Conventionally, mineral fiber-based sound absorbing materials such as glass wool have been used to control unnecessary reflected sound as a noise countermeasure. However, such a sound-absorbing material has a problem in moisture resistance and weather resistance, for example, when it contains water, the sound-absorbing performance is remarkably lowered or it is deformed over time. Therefore, recently, a porous ceramic sound-absorbing material excellent in moisture resistance and weather resistance has been developed (see Patent Document 1).

JP 2002-193684 A

  On the other hand, a sound absorbing material is also used for room acoustic control. For example, in a room, sound may be repeatedly reflected by opposing wall surfaces, which is perceived as an acoustic disturbance. In addition, interference between direct sound and reflected sound in an audio space or the like, or reflected sound from a wall surface can also be an acoustic obstacle. In order to prevent such an acoustic disturbance, a mineral fiber-based sound absorbing material such as glass wool is often used.

  However, since the sound absorbing material is mainly intended to absorb sound, if it is used extensively, the acoustic energy of the entire room is reduced, and the sound is not echoed or glossy. Also, in a space such as a home theater, the sense of reality is impaired and the three-dimensional sound effect can be an unnatural factor. This is the same even when a porous ceramic sound absorbing material is used. Therefore, there has been a demand for a material that can absorb sound appropriately and prevent acoustic disturbance while maintaining acoustic energy to some extent.

  The present invention has been made in view of such a background, and has a sound characteristic capable of simultaneously realizing sound absorption and diffusion, and a method for producing a porous ceramic acoustic material excellent in moisture resistance and weather resistance, and an acoustic structure Is intended to provide a body.

The method for producing a porous ceramic acoustic material according to the first aspect of the present invention includes a filling step of filling a mold in a non-pressurized state with a granular tile material containing at least silicon carbide as a foaming agent, A firing step of firing the unpressurized tile raw material in the mold at a temperature of 1150 ° C. or higher, and unevenness having repetition of the frequency of the frequency of the sound to be diffusely reflected in order to diffusely reflect the incident sound And forming a diffusion uneven portion having a height at which the double normalized standard deviation curve is about 0 in a double normalized standard deviation curve (DNSD). And

  In the method for producing a porous ceramic acoustic material, in the firing step, the tile raw material filled in an unpressurized state (not pressurized) in the mold is fired at a temperature of 1150 ° C. or higher. Therefore, when the tile material is melted and softened, the tile material is foamed and expanded by the foaming agent (silicon carbide). And the particle | grain surfaces of a tile raw material contact and join moderately during baking, and many space | gap (pores) are formed between particle | grains. Thereby, a porous ceramic acoustic material having a sufficient sound absorption coefficient can be obtained.

  Moreover, since the tile raw material filled in the mold is fired, a porous ceramic acoustic material having a desired shape can be obtained while the foaming and expansion of the tile raw material are moderately suppressed by the mold and sufficient strength is ensured. . Thereby, a porous ceramic acoustic material having a high degree of freedom in shape having a diffusion shape matched to a frequency at which a diffusion effect is expected can be easily obtained simply by changing the shape of the mold. Moreover, since the tile raw material is used as a raw material, a porous ceramic acoustic material excellent in moisture resistance and weather resistance can be obtained.

  Therefore, the porous ceramic acoustic material obtained by the production method of the present invention can simultaneously achieve sound absorption and diffusion. In particular, since the incident sound can be diffused and reflected by the diffusion effect while reducing the acoustic energy by the sound absorption effect, it can be effectively utilized not only for noise countermeasures but also for room acoustic control. In other words, while maintaining the acoustic energy of the space to some extent, the reflected sound can be scattered to prevent acoustic disturbances, so that a natural sounding space can be created. Further, in addition to such effects, it is also excellent in moisture resistance and weather resistance, and therefore has high utility value including outdoor installation.

  An acoustic structure according to a second aspect of the present invention includes an acoustic part made of a porous ceramic acoustic material produced by the method for producing a porous ceramic acoustic material, and a wall disposed on the back side of the acoustic part. It is characterized by having a body.

  The acoustic structure of the present invention can achieve sound absorption and diffusion simultaneously with an acoustic part made of a porous ceramic acoustic material, and is excellent in moisture resistance and weather resistance. Moreover, if the porosity, shape (diffusion shape), etc. of the porous ceramic acoustic material constituting the acoustic part are adjusted, the sound absorption effect and the diffusion effect can be easily controlled.

  Thus, according to the present invention, there are provided a method for producing a porous ceramic acoustic material and an acoustic structure having acoustic characteristics capable of simultaneously realizing sound absorption and diffusion, and having excellent moisture resistance and weather resistance. Can do.

  Here, in the method for producing the porous ceramic acoustic material, in the firing step, the tile raw material is fired at a temperature of 1150 ° C. or higher. When firing at a temperature lower than 1150 ° C., it becomes difficult to foam and expand the tile material with a foaming agent (silicon carbide) in a timely manner in a state where the tile material is melted and softened. Therefore, the sound absorption coefficient of the obtained porous ceramic acoustic material is lowered.

  In the firing step, the tile raw material is preferably fired at a temperature of 1200 ° C to 1270 ° C. In this case, in the firing step, the tile raw material can be foamed and expanded by the foaming agent (silicon carbide) with good timing in a state where the tile raw material is melted and softened. Thereby, a porous ceramic acoustic material having a sufficient sound absorption coefficient can be obtained with certainty.

  Moreover, it is preferable that content of the silicon carbide in the said tile raw material is 0.1 mass% or more. In this case, in the firing step, the tile raw material can be well foamed and expanded with silicon carbide as a foaming agent. In addition, what is necessary is just to adjust content of the silicon carbide by the characteristic of the porous ceramic acoustic material to obtain, for example, can be 10 mass% or less.

  Moreover, the average particle diameter of the said tile raw material is good also as 0.5-1 mm. In this case, the porosity of the obtained porous ceramic acoustic material can be sufficiently increased. That is, the sound absorption coefficient of the obtained porous ceramic acoustic material can be sufficiently increased. In order to sufficiently increase the porosity (sound absorption rate), the average particle diameter is preferably 0.7 to 1 mm. When the average particle size is less than 0.5 mm, the porosity and further the sound absorption rate of the obtained porous ceramic acoustic material may be reduced. On the other hand, if it exceeds 1 mm, it may be difficult to produce granular tile raw materials with high accuracy.

  Moreover, as the tile raw material, for example, a general tile raw material containing clay, feldspar, porcelain stone, limestone, talc and the like can be used. Moreover, the ceramic industry waste soil (recycled raw material) may be contained as a part of the tile raw material. Further, a pore forming agent may be added to the tile raw material in order to increase the porosity. As the pore-forming agent, an organic substance (for example, coffee grounds) that is burned off during firing can be used.

  The porosity of the porous ceramic acoustic material is preferably 30% or more. In this case, the sound absorption coefficient of the porous ceramic acoustic material can be sufficiently ensured. Moreover, if the porosity is 50% or more, the sound absorption rate can be further increased. It should be noted that the porosity of the porous ceramic acoustic material may be set to be not more than a porosity that can ensure sufficient strength, for example, 70% or less.

  In addition, since the sound absorption rate can be controlled by adjusting the porosity of the porous ceramic acoustic material, porous ceramic acoustic materials having the same design and different acoustic characteristics can be obtained. By randomly arranging such porous ceramic acoustic materials, it is possible to realize a diffusion effect in a wider range than the frequency expected for the diffusion shape without being restricted by design.

  Further, the porous ceramic acoustic material may be provided with a diffusing uneven portion for diffusing and reflecting incident sound. In this case, the diffusion effect is sufficiently obtained by the diffusion uneven portion. In addition, what is necessary is just to form a diffusion uneven | corrugated | grooved part in the part into which a sound enters among porous ceramic acoustic materials. Moreover, the shape (diffusion shape) from which the diffusion effect is obtained is not limited to the diffusion uneven portion, and various shapes can be employed. In addition, by providing a shape that matches the frequency at which the diffusion effect is expected, it is possible to design and realize a moderate and flat sound absorption characteristic from low to high.

  In addition, for the design of the diffusion shape, it is possible to use a technique such as selecting the height at which DNSSD is approximately zero in a DNSD (Double Normalized Deviation) curve with irregularities having repetitions of about the wavelength of the target frequency. it can. If a convex shape having a certain width and height is employed, it is possible to design a diffusion shape having a relatively arbitrary design even if it is not so strict. Further, when it is desired to reflect the reflected sound (remaining sound absorption energy) in a certain predetermined direction in noise countermeasures or room acoustic control, the specular reflection angle may be adjusted and designed.

  The acoustic structure may further include an air layer formed by providing a predetermined clearance between the acoustic part and the wall body. In this case, the sound absorption coefficient at a specific frequency (sound range) can be controlled by adjusting the air layer (clearance).

  Moreover, in the acoustic structure, the clearance between the acoustic part and the wall body is preferably 50 mm or more. In this case, it is possible to increase the sound absorption rate particularly in the mid-low range.

  In addition, the porous ceramic acoustic material and the acoustic structure using the porous ceramic acoustic material can simultaneously absorb and diffuse sound and have design freedom. This is a great advantage in designing interior acoustic interiors, from space to large spaces such as auditoriums, gymnasiums, and indoor pools. Moreover, since it is excellent also in moisture resistance, the utility value in large spaces, such as an indoor pool, becomes high.

(A)-(d) It is explanatory drawing which shows the process of filling a tile raw material in a filling container. (A) It is a perspective view which shows a porous ceramic acoustic material, (b) It is a photograph which shows a porous ceramic acoustic material. It is a SEM photograph of a porous ceramic acoustic material, (a) is 50 times magnification, (b) is 100 times magnification. It is a section explanatory view showing the composition of an acoustic structure. It is a graph which shows the measurement result of normal incidence sound absorption coefficient of an acoustic structure (samples E1-E4, C1-C4).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)
In the present embodiment, a method for producing a porous ceramic acoustic material of the present invention will be described.

  As shown in FIGS. 1 and 2, the method for producing a porous ceramic acoustic material includes a filling step of filling a mold 8 with a granular tile raw material 10 containing at least silicon carbide as a foaming agent in an unpressurized state. And a firing step of firing the unpressurized tile raw material 10 in the mold 8 at a temperature of 1150 ° C. or higher. This will be described in detail below.

  In producing the porous ceramic acoustic material 1 (FIG. 2), a tile raw material as a raw material is prepared. The components of the tile raw material used in this embodiment and the content thereof are as follows: Ceramic waste (recycled raw material): about 30% by mass, clay: about 28% by mass, feldspar: about 36% by mass, ceramic stone: about 6% by mass , Foaming agent (silicon carbide): 0.1 to 0.2% by mass. The breakdown of the ceramic industry waste soil is Asahi Minamata clay: about 12% by mass, Shigaraki feldspar class C: about 18% by mass.

  Next, the tile raw material is wet-pulverized (pulverized and mixed with the liquid). Specifically, the tile raw material is put into a ball mill together with water and cobblestone, and the tile raw material is pulverized by impact between the cobblestones. Then, the slurry after the wet pulverization is spray-dried so as to have a predetermined moisture to obtain a granular tile raw material. In addition, the average particle diameter of a tile raw material is 0.5-1 mm (in this embodiment, 0.7-1 mm).

  Next, a filling process is performed. Specifically, as shown in FIG. 1A, a molding part 81 that is a part of the molding die 8 is prepared. The molded part 81 is configured so that the finally obtained porous ceramic acoustic material 1 (FIG. 2) has a diffusing shape for diffusing and reflecting incident sound (a diffusion uneven part 13 shown in FIG. 2 described later). Yes. The forming portion 81 of the present embodiment has three concave portions 811 having a substantially triangular cross section. Then, as shown in FIG. 1 (b), the granular tile raw material 10 is rubbed into the molding part 81 through the opening 812 of the molding part 81.

  Thereafter, as shown in FIG. 1 (c), a lid portion 82, which is a part of the molding die 8, is placed over the opening 812 of the molding portion 81, and as shown in FIG. The mold 8 is turned upside down so that the lid 82 is on the lower side. Thereby, the tile raw material 10 is filled in the molding die 8 (the molding part 81 and the lid part 82) in an unpressurized state (a state where no pressure is applied). In addition, although the ceramic earthenware is used as the shaping | molding die 8, a ceramic continuous bowl etc. may be used.

  Next, a firing step is performed. Specifically, the mold 8 filled with the unpressurized tile raw material 10 is placed in a firing furnace, and the tile raw material 10 is fired at a temperature of 1200 to 1270 ° C. In the firing step, the tile raw material 10 is heated at a high temperature and melted and softened. At this timing, the tile material 10 is expanded and expanded by the foaming agent (silicon carbide). Thereby, the particle | grain surfaces of the tile raw material 10 contact and join moderately during baking, and many space | gap (pores) are formed between particles.

  Next, the fired body is cooled. At this time, since the volume shrinkage occurs in the fired body, a gap is formed between the fired body and the mold 8, and the fired body is easily detached from the mold 8. Thereafter, the fired body is taken out from the mold 8. Thus, the porous ceramic acoustic material (fired body) 1 is obtained.

  As shown in FIG. 2 (a), the porous ceramic acoustic material 1 has a substantially rectangular plate-like bottom part 11 and three convex parts 12 having a substantially triangular cross-section projecting upward from the bottom part 11. Yes. On one side of the bottom portion 11 of the porous ceramic acoustic material 1 (side on which sound is to be incident), three projecting portions 12 are arranged in parallel at a predetermined interval, so that an incident sound is obtained. A diffusion uneven portion 13 is formed to diffusely reflect the light. FIG. 2B is a photograph showing an actual porous ceramic acoustic material.

  Further, the porosity of the porous ceramic acoustic material 1 is 30% or more. When the porosity of the two sample products of the porous ceramic acoustic material 1 of the present embodiment was measured, it was 51.9% and 52.3%, respectively, and the average value was 52.1%. The porosity (apparent porosity) was measured according to JIS R 2205.

Next, the function and effect of this embodiment will be described.
In the method for producing the porous ceramic acoustic material of the present embodiment, in the firing step, the tile raw material 10 filled in an unpressurized state (not pressurized) in the mold 8 is fired at a temperature of 1150 ° C. or higher. Therefore, when the tile raw material 10 is melted and softened, the tile raw material 10 is expanded and expanded by the foaming agent (silicon carbide). And the particle | grain surfaces of the tile raw material 10 contact and join moderately during baking, and many space | gap (pores) are formed between particle | grains. Thereby, the porous ceramic acoustic material 1 having a sufficient sound absorption coefficient is obtained.

  Here, in FIG. 3, the SEM photograph of the porous ceramic acoustic material 1 is shown. The magnification is 50 times in FIG. 3A and 100 times in FIG. 3B. From the SEM photograph shown in FIG. 3, it can be seen that the particle surfaces of the tile raw material 10 appropriately contacted and joined during firing, and many voids (pores) were formed between the particles.

  In addition, since the tile raw material 10 filled in the mold 8 is fired, the foam 8 of the tile raw material 10 is moderately suppressed by the mold 8 and sufficient strength is ensured while the desired shape of the porous ceramic acoustic wave is obtained. Material 1 is obtained. Thereby, the porous ceramic acoustic material 1 having a high degree of freedom in shape having a diffusion shape that matches the frequency at which a diffusion effect is expected can be easily obtained by simply changing the shape of the mold 8. Moreover, since the tile raw material 10 is used as a raw material, the porous ceramic acoustic material 1 excellent in moisture resistance and weather resistance can be obtained.

  Therefore, the porous ceramic acoustic material 1 obtained by the manufacturing method of the present embodiment can simultaneously achieve sound absorption and diffusion. In particular, since the incident sound can be diffused and reflected by the diffusion effect while reducing the acoustic energy by the sound absorption effect, it can be effectively utilized not only for noise countermeasures but also for room acoustic control. In other words, while maintaining the acoustic energy of the space to some extent, the reflected sound can be scattered to prevent acoustic disturbances, so that a natural sounding space can be created. Further, in addition to such effects, it is also excellent in moisture resistance and weather resistance, and therefore has high utility value including outdoor installation.

  In the present embodiment, the tile raw material 10 is fired at a temperature of 1200 ° C. to 1270 ° C. in the firing step. Therefore, in the firing step, the tile raw material 10 can be foamed and expanded by the foaming agent (silicon carbide) with good timing in a state where the tile raw material 10 is melted and softened. Thereby, the porous ceramic acoustic material 1 having a sufficient sound absorption coefficient can be obtained reliably.

  Moreover, content of the silicon carbide in the tile raw material 10 is 0.1 mass% or more. Therefore, in the firing step, the tile raw material 10 can be foamed and expanded satisfactorily with silicon carbide as a foaming agent.

  Moreover, the average particle diameter of the tile raw material 10 is 0.5-1 mm. Therefore, the porosity of the obtained porous ceramic acoustic material 1 can be sufficiently increased. That is, the sound absorption coefficient of the obtained porous ceramic acoustic material 1 can be sufficiently increased. In the present embodiment, the average particle diameter of the tile raw material 10 is set to 0.7 to 1 mm in order to sufficiently increase the porosity (sound absorption rate).

  Further, the porosity of the porous ceramic acoustic material 1 is 30% or more. Therefore, the sound absorption coefficient of the porous ceramic acoustic material 1 can be sufficiently ensured. In the present embodiment, the porosity of the porous ceramic acoustic material 1 is 50% or more, and the sound absorption rate can be further increased.

  Further, a diffusion uneven portion 13 for diffusing and reflecting incident sound is formed on the porous ceramic acoustic material 1 on the side on which sound is to be incident. Therefore, the diffusion effect is sufficiently obtained by the diffusion uneven portion 13.

  Thus, according to the method for producing a porous ceramic acoustic material of the present embodiment, the porous ceramic acoustic material 1 has acoustic characteristics capable of simultaneously realizing sound absorption and diffusion, and is excellent in moisture resistance and weather resistance. Is obtained.

(Embodiment 2)
In this embodiment, the acoustic structure of the present invention will be described.
As shown in FIG. 4, the acoustic structure 2 includes an acoustic part 21 made of the porous ceramic acoustic material 1 and a wall body 22 disposed on the back side of the acoustic part 21. This will be described in detail below.

  As shown in the figure, in the acoustic structure 2, a wall body 22 is disposed on the back side of the acoustic unit 21 (the side opposite to the side on which sound is to be incident). That is, the acoustic part 21 is disposed on the front side of the wall body 22 with a predetermined clearance C. The acoustic unit 21 is composed of the porous ceramic acoustic material 1 manufactured by the manufacturing method of the first embodiment. Specifically, the porous ceramic acoustic material 1 having a substantially quadrangular panel shape is arranged vertically and horizontally on substantially the same plane.

  The porous ceramic acoustic material 1 is disposed so that the diffusion uneven portion 13 (convex portion 12) is on the front side of the acoustic portion 21 (side on which sound is to be incident). Further, the bottom portion 11 of the porous ceramic acoustic material 1 is supported by a support body (not shown) disposed between the wall body 22 and the bottom body 11. An air layer 23 is formed between the acoustic unit 21 and the wall body 22. The thickness of the air layer 23, that is, the clearance C between the acoustic part 21 and the wall body 22 is 50 mm or more.

Next, the function and effect of this embodiment will be described.
The acoustic structure 2 of the present embodiment can realize sound absorption and diffusion at the same time by the acoustic part 21 made of the porous ceramic acoustic material 1, and is excellent in moisture resistance and weather resistance. Moreover, if the porosity, shape (diffusion shape), etc. of the porous ceramic acoustic material 1 which comprises the acoustic part 21 are adjusted, a sound absorption effect and a diffusion effect can be controlled easily.

  In the present embodiment, the acoustic structure 2 further includes an air layer 23 formed by providing a predetermined clearance C between the acoustic unit 21 and the wall body 22. Therefore, by adjusting the air layer 23 (clearance C), the sound absorption rate at a specific frequency (sound range) can be controlled. Moreover, the clearance C (thickness of the air layer 23) between the acoustic part 21 and the wall body 22 is 50 mm or more. Therefore, it is possible to increase the sound absorption rate particularly in the mid-low range.

  As described above, according to the present embodiment, the acoustic characteristics can be controlled by using the porous ceramic acoustic material 1 having acoustic characteristics capable of simultaneously realizing sound absorption and diffusion, and having excellent moisture resistance and weather resistance. The acoustic structure 2 which is possible and excellent in moisture resistance and weather resistance is obtained.

  In this embodiment, as shown in FIG. 4, the air layer 23 (clearance C) is provided between the acoustic part 21 of the acoustic structure 2 and the wall body 22, but the acoustic part is formed on the surface of the wall body 22. Alternatively, the air layer 23 (clearance C) may not be provided.

(Experimental example)
In this experimental example, the acoustic characteristics of a porous ceramic acoustic material and an acoustic structure using the same are evaluated.

  In this experimental example, as an example of the present invention, a porous ceramic acoustic material having a diffusion shape (diffusion concavo-convex portion) manufactured by the manufacturing method of Embodiment 1 is used, and an air layer between the acoustic portion and the wall body is used. Four acoustic structures (samples E1 to E4) having different thicknesses (clearances) were prepared. The clearances of the samples E1 to E4 are 0 mm, 50 mm, 75 mm, and 100 mm, respectively. The configuration of the acoustic structure is the same as that of the second embodiment.

  In addition, as a comparative example, four flat ceramic acoustic materials having no diffusion shape (diffusion concavo-convex portion) and four different air layer thicknesses (clearances) between the acoustic portion and the wall body are used. An acoustic structure (samples C1 to C4) was prepared. The clearances of samples C1 to C4 are 0 mm, 50 mm, 75 mm, and 100 mm, respectively. The method for producing the porous ceramic acoustic material is basically the same as that of the first embodiment, except that the shape of the mold is different. The configuration of the acoustic structure is the same as that of the second embodiment.

  The acoustic characteristics were evaluated by measuring the normal incidence sound absorption coefficient for the acoustic structures of the samples (E1 to E4, C1 to C4). The normal incident sound absorption coefficient was measured according to JIS A 1405.

  FIG. 5 shows the measurement results of the normal incidence sound absorption coefficient. As shown in the figure, the samples E1 to E4, which are embodiments of the present invention, have a higher sound absorption rate as the air layer thickness (clearance) increases in the mid-low range (100 to 500 Hz). Further, in the high sound range with a peak at 500 Hz, the sound absorption coefficient tends to be substantially the same or slightly decreased even when the thickness (clearance) of the air layer increases.

  Moreover, under the condition that the thickness (clearance) of the air layer is the same, the samples E1 to E4 as examples of the present invention and the samples C1 to C4 as comparative examples have no difference in sound absorption coefficient at 100 Hz, but 200 Hz or more. Then, the sound absorption coefficient of the samples E1 to E4 becomes higher, and the difference between them becomes larger. This is considered to be because the porous ceramic acoustic material constituting the acoustic part of the acoustic structures of the samples E1 to E4 has a diffusion shape (diffusion uneven part). That is, it is considered that the porous ceramic acoustic material diffuses and reflects the incident sound by the diffusion shape while absorbing sound appropriately.

  From the above results, it has been found that the porous ceramic acoustic material produced by the method for producing a porous ceramic acoustic material of the present invention and the acoustic structure using the same can achieve sound absorption and diffusion simultaneously. It was also found that by adjusting the shape of the porous ceramic acoustic material and the structure of the acoustic structure (for example, the thickness of the air layer), excellent acoustic characteristics (sound absorption characteristics) from low to high sounds can be obtained.

  In addition, this invention is not limited to the above-mentioned embodiment at all, and it cannot be overemphasized that it can implement with a various aspect in the range which does not deviate from this invention.

DESCRIPTION OF SYMBOLS 1 ... Porous ceramic acoustic material 10 ... Tile raw material 13 ... Diffusion uneven part 2 ... Acoustic structure 21 ... Acoustic part 22 ... Wall body 23 ... Air layer 8 ... Mold C ... Clearance

Claims (8)

A filling step in which a granular tile raw material containing at least silicon carbide as a foaming agent is filled in a mold in an unpressurized state;
A firing step of firing the unpressurized tile raw material in the mold at a temperature of 1150 ° C. or higher ;
In order to diffusely reflect the incident sound, the double normalized standard deviation curve has a height where the double normalized standard deviation curve is about 0 in the unevenness having repetition of the wavelength of the frequency of the sound to be diffusely reflected. Forming a diffusion rugged portion having
A method for producing a porous ceramic acoustic material, comprising:   2. The method for producing a porous ceramic acoustic material according to claim 1, wherein in the firing step, the tile raw material is fired at a temperature of 1200 ° C. to 1270 ° C. 3.   The method for producing a porous ceramic acoustic material according to claim 1 or 2, wherein a content of silicon carbide in the tile raw material is 0.1 mass% or more.   The average particle diameter of the said tile raw material is 0.5-1 mm, The manufacturing method of the porous ceramic acoustic material of any one of Claims 1-3 characterized by the above-mentioned.   The porosity of the said porous ceramic acoustic material is 30% or more, The manufacturing method of the porous ceramic acoustic material of any one of Claims 1-4 characterized by the above-mentioned. An acoustic part comprising a porous ceramic acoustic material produced by the method for producing a porous ceramic acoustic material according to any one of claims 1 to 5 , and
An acoustic structure comprising a wall disposed on the back side of the acoustic unit. The acoustic structure according to claim 6 , further comprising an air layer formed by providing a predetermined clearance between the acoustic part and the wall body. The acoustic structure according to claim 7 , wherein the clearance between the acoustic part and the wall body is 50 mm or more.