Acquisition of exterior multiple sound sources for train auralization based on beamforming
RWTH Aachen University
Tuesday 2 june, 2015, 17:20 - 17:40
0.1 London (90)
The auralization of train exterior noise requires not only the identification of different sound sources, but also the separated signal from each source. A virtual sound could not sound convincing if it is created by pure synthesis method without actual recordings, especially when there are multiple moving sources. Beamforming has been proved qualified to solve the identification and localization problems of multiple moving sound sources from trains, however, for auralization these information are not enough. This paper focuses on capturing the sound source signals from a running train by the method of beamforming for auralization. Beamforming is applied to identify the major sound sources and obtain their spatial distribution, and the recordings are used as actual signals for the synthesis as well. A microphone array is mounted along the railway side to carry out the measurement, which includes measuring the exterior noise from different types of trains at different speeds. With subsequent post-processing, the main sound sources are localized and identified. According to the spectra of the recordings, the sound sources are allocated separately to tonal and broadband components. The tones are generated by the propulsion system, while wheels, pantograph and coaches contribute mainly to the broadband part, namely rolling noise and aerodynamic noise. Finally, it is discussed how these individual signals can serve for the auralization of the complete train.
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