A STUDY ON THE ACOUSTIC PERFORMANCE TEST METHOD USING SPEAKER OF A NOISE REDUCTION DEVICE FOR NOISE REDUCTION OF THE 400KM/H CLASS HIGH-SPEED RAILROAD

摘要

For the purpose of the acoustic performance evaluation of noise reduction device (NRD) installed at the top of noise barrier for further decreasing of noise level of 400km/h class high-speed railroad (HEMU), the acoustic performance test method using speaker instead of really running railway vehicle was suggested in this paper. For this, noise source location and frequency spectrum of HEMU was analyzed through the field noise test. These data were used for the determination of speaker's installation positions and frequency correction values applied to the speaker noise source. And, 400 meters long NRD was installed at test site where HEMU will be running at a speed of 400km/h. Finally, the outdoor speaker test results with and without NRD showed that this NRD could decrease noise level even more than 3dB(A). In the future, the acoustic performance results of NRD conducted with speaker test will be compared with that of field test for HEMU running at a speed of 400km/h.