| 摘要 |
To absorb a noise produced by an external force that generates an audio frequency even if it is applied thereto, and to make it hard to become a noise source to a surrounding area. It includes a surface layer 20 having microscopic pores 21 formed on a surface 20A, communicating passages 24 communicating with the microscopic pores 21 and a porous layer 10 having sound pores 14 that are formed at an inner part deeper than the surface layer 20 having the microscopic pores 21 formed, communicate with the communicating passage 24 and that have a volume larger than volumes of the microscopic pore 21 formed on the surface 20A and the communicating passage 24. A sound absorption characteristic and/or a sound insulation characteristic is provided by the microscopic pores 21 of the surface 20A, the communicating passages 24 of the porous layer 10, and the sound pores 14 of the porous layer 10. Accordingly, sound absorption control including sound insulation in a predetermined audio frequency band can be achieved and a high sound absorption characteristic can be provided.
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