Abstract
Concerning the on-vehicle-type ANC devices based on the wave absorption principle for wheel / rail system, new concept of device construction was proposed to prevent the howling and to realize downsizing , i.e., the secondary sound actuator is to be separated from the detecting microphone of primary noise by the distances of 1/2, 3/8 and 1/4 times of wave length of dominant frequency (800Hz) of rolling noise. The validity of new idea was first ascertained by means of BEM simulation analysis and then the experiments using three kinds of devices were actually executed, showing the improved ANC effects for the fairly high primary noise level almost comparable to the practical level
