| 摘要 |
PURPOSE:To display an excellent noise reduction effect by generating a test signal from a control sound source when an acoustic level in an acoustic space is high, computing a transmission function(TF) based on the detection signal of a residual noise detecting means, sending the computed result to a control means, and updating the TF included in control algorithm. CONSTITUTION:When the acoustic level in the acoustic space is comparatively high, a controller 10 outputs a test signal to loud speakers 7a to 7d to be control sound source, microphones 8a to 8h to be a residual noise detecting means detect the test sound, TFs between the control sound sources and the residual noise detecting means are computed based on the detection signals and the TFs of the controller 10 including the TFs in its control algorithm are successively updated by the computed TFs. Since a driving signal for driving the control sound sources by the optimum TF following a TF change due to a temperature change or the like in the acoustic space can be obtained from the controller 10, the noise reduction effect in the acoustic space can be improved. |
