| 摘要 |
PURPOSE:To enable substantially lowering by means of a device of simple constitution the sound pressure radiated from the air-conditioning duct independent of changes in the operating condition of an air-conditioning device. CONSTITUTION:An air-conditioning duct 12 conveys a current of air from a blower 11a in an air conditioner 11. Inside the air-conditioning duct 12 a microphone (sound receiver for the control) 13 provided near the air conditioner 11 detects the noise from the air conditioner 11. A plurality of evaluating microphones 14a-14d provided downstream in the air-conditioning duct 12 detect the noise at the point under control. From the condition of the sound-deadening effect monitored by the evaluating microphones 14a-14d, a controller 16 obtains the sum total of the sound pressures with respect to all of the evaluating microphones 14a-14d; on the basis of a transfer function between the microphone 13 and the evaluating microphones 14a-14d having the sum total of the sound pressures at the minimums, the controller 16 corrects the operational factor; and on the basis of the corrected factor, the controller 16 processes a signal and outputs it at a speaker (sound producer for the control) 15. |
