Experimental study of active noise control in high-speed train carriage based on laboratory reproduced noise

To reduce the low-frequency noise in the carriage of a high-speed train, active noise control over a large area of the carriage is studied. A 48-channel feed forward active control system is designed based on the measured noise spectrums of the high-speed train and the sizes of the target area (1.8 m×2.5 m×1.3 m). According to well-balanced arrangements, the secondary sources are placed on the five surfaces in the carriage except bottom and the error points are distributed in the target area. The off-line calculation and control of filter operating states are performed by measuring acoustic transfer functions of acoustic paths. The noise reduction experiment in the carriage is carried out in a semi-anechoic room, and the sound field reproduction system outside the carriage is used to generate the primary noises at four train speeds. The noise reduction performances of the active control system are measured, and the system performances for different primary noises and different reference signals are analyzed. The results show that by taking the vibration signals of carriage window as reference signals, an average noise reduction of 3.1~4.7 dB(A) can be obtained at 48 measurement points in the target area for the primary noises at different train speeds. The feasibility of the active control system for noise reduction in a large area is verified.