Abstract:
Active noise control (ANC) is a technique which can reduce low-frequency noise effectively. The physical effects of an ANC system have been studied by many researchers; however, it is also requested to evaluate ANC systems from the viewpoint of the psychological effects on listeners. On the other hand, general noise assessments have been carried out by the equivalent noise level criteria such as the L[inf Aeq]. Indeed, the L[inf Aeq] is a well-designed judgment criterion; however, the evaluation using the L[inf Aeq] criterion includes an A-weighted filtering. This may cause problems to occur when we treat noise that contains a lot of low-frequency noise components rather than high-frequency components. That is to say, even if the equivalent sound level is small, the low-frequency noise may annoy, and cause harmful effects to, the listener in different ways than the high-frequency noise. The purpose of this paper is to evaluate the effects of an ANC system on human hearing by carrying out a series of experiments. The subjective evaluations revealed the significant effects of ANC in the form of psychological space expressions.