| 摘要 |
PROBLEM TO BE SOLVED: To provide a sound absorbing device coping with noise whose frequency vary in time and position. SOLUTION: In the device, a resonance space 16 is defined as the space surrounded by a wall body 15 made of a front surface wall 12, a firm wall 13, which is arranged opposing to the wall 12 with a gap, and a connecting wall 14, which connects the peripheral sections of the walls 12 and 13. An entrance 17 is provided on the wall 12 to connect the space 16 to the external. At least one of the walls 12 or 13 is made freely movable between the wall 14 in the direction closing to the other side or separating from the other side while maintaining airtighness.
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