| 摘要 |
PROBLEM TO BE SOLVED: To obtain an acoustical panel which is light in weight and simple in structure, lessens the noise of a wide range from a low-frequency tone to a high-frequency tone and has durability and versatility. SOLUTION: This acoustical panel comprises a thin film 11 which is regularly fixed with button-like weights 12 apart nearly specified intervals and has rigidity, a steel sheet 13 which is arranged to face apart a specified spacing from this thin film 11, spacing holding members 15 which hold the specified spacing between the steel sheet 13 and the thin film 11 and glass wool 14 inserted into the space between the steel sheet and the thin film, as double structure walls. The entire part vibration induced by acoustic waves and the partial vibration generated by the division by the weight 12 negative each other to attenuate the entire part vibration, thereby lessening the propagation of the low-frequency noise. At the same time, the noise of high-frequency is reflected by the steel sheet 13 and the noise is insulated. The noise of the resonance frequency made to remain by multiple reflections between the thin film and the steel sheet is absorbed by the glass wool 14 inserted in-between.
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