Temporal and spectral characteristics of public address announcements in subway platforms with various finishing materials using computer simulation

摘要

In subway platforms, the sound signals and announcements, containing urgent information such as an accident as well as indications of train-coming or destination, are delivered through public address (PA) loudspeakers as an important sound source. Various acoustic environments by platform designs, such as dimension or materials, are closely related to propagation and perception of PA announcements. This study investigates the effects of platform design elements such as finishing materials on temporal and spectral characteristics of PA announcements. In order to alter design condition systematically, two subway spaces with island platform are constructed using computer simulation. Then, it is acoustically matched to the field measurement results in terms of room acoustic parameters. Sound sources of the announcements are collected according to the announcing purposes (train movements, door operation and others). Auralized announcements in simulation model are evaluated in terms of sound pressure levels and auto-correlation/interaural cross-correlation factors in both time and frequency domains according to various combination of finishing materials (floor, wall and ceiling). As results, the acoustic design directions of platform spaces is discussed for improving sound quality and speech intelligibility of PA announcements.