| 摘要 |
PROBLEM TO BE SOLVED: To provide a sound absorbing structure that can be made see-through. SOLUTION: A perforated plate 1 is formed which is provided with a number of evenly or unevenly spaced pores 2. The aperture of the perforated plate 1 is determined so that the surface impedance of the perforated plate 1 with respect to the frequency at which to absorb sounds approximates the impedance determined by the product of the density of air and sound velocity, while taking into account mass resistance when air in spaces in the pores 2 is to be vibrated, frictional resistance on the edges of the pores 2, and radiation resistance when sound waves are to be radiated via air in the spaces in the pores 2.
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