Active noise control(ANC) is a method to reduce unwanted noise by generating opposite phase sound by control speaker. For the most popular feedforward ANC system, it consists of reference sensor, control speaker and error sensor. Reference sensor detects noise signal near by noise source, control speaker generates opposite phase sound of disturbance noise and error sensor estimates disturbance noise. For example, in single input single output system(1 reference sensor, 1 control speaker, 1 error sesnor) reference sensor is placed near by noise source and control speaker is placed closer to control area than the reference sensor considering causality and error sensor is placed at control area. But when the system becomes more complicated and control area becomes larger, we don’t know where the noise source. Also, we don’t know where and how many sensors and actuatosrs should be placed. The maximum reduction performance of active noise control system is dominant in the configuration of sensors and actuators. So, we need performance measure that can evaluate whether the sensors and actuators are correctly located. Previously, there were several indicators such as causality, coherence between reference signal measured at reference sensor and disturbance noise to determine configuration of sensors and actuators. But there was a lack of systematic ways to view them. In this paper, we propose performance measure based on the reduction performance of active nosie control systems for the configuration of sensors and actuators. Proposed performance measure can represent the previous indicator’s characteristics comprehensively. We analyzed about this proposed performance measure and researched about the impact of configuration of sensors and actuators. Finnally, several ANC situations have analyzed by the proposed performance measure.
 

active noise control,performance measure