Influence of the Doppler effect and binaural characteristics on perceived annoyance of train pass-by noise

Abstract

High-speed train has advantages on large seating accommodation among green transportation systems. Commercial trains continuously increase its operation speed to reduce the travel time. The noise generated from railway operation prevents nearby residential areas from quiescent and comfortable living space. When evaluating the noise annoyance caused by high-speed train operations, it is necessary to consider the acoustic characteristics as well as its magnitude. In particular, the pass-by noise has a rapid frequency shift due to the Doppler effect of moving noise source. In this study, a simple wave field model is proposed to reflect the Doppler effect and binaural characteristics. The noise emitted from an operating high-speed train (KTX) was measured, and the spectral characteristics were analyzed. The frequency shifts due to the Doppler effect were observed. The rolling and aerodynamic noise generated from the inter-coach space contributed to the pass-by noise. To investigate the effects of the Doppler effect, the moving sounds were synthesized with the frequency shift at the corresponding bands. The synthesized sounds were convolved with a simple head-related transfer function to represent the binaural characteristics. The pairwise comparison method was used for auditory annoyance evaluation of the synthesized moving sound stimuli and quantification of the Doppler effect. It was determined that the Doppler frequency shift reduced annoyance of the moving sound source. This reduction appeared only when binaural effects were considered together with the frequency shift. The identified influence of the Doppler effect helps to understand the railway noise bonus compared to those from other transportation systems.