Room acoustic design to improve speech privacy in passenger cars of high-speed trains

Abstract

In the present study, room acoustic environments in high-speed trains were investigated to identify design elements for passenger cars. Absorption coefficients of the interior finish materials were tested, and reverberation time (RT) and sound pressure level (SPL) were measured at the ear height of passengers. A room acoustic simulation model for the passenger cars was constructed from actual measurements carried out at different positions in the passenger cars. Design elements were identified and classified through computer modelling of different interior surfaces with different absorption coefficients. It was found that appropriate absorptive material and ceiling shape help improve speech privacy inside passenger cars. The privacy distance (rP) improved by 2.7 m by increasing the absorption coefficients and by 1.8 m by adding ceiling banners.