Sound propagation and scattering in performance halls with balconies

Abstract

Numerous concert halls and auditoria in Hong Kong have been built and used for decades. Most of the halls in this congested city are designed for multi-purpose use and built with balconies for maximizing the space use. While objective and subjective evaluations on acoustic properties of performance halls have been done around the world, it is time for Hong Kong to have her own systematic research. Measurements have been done in a fan-shaped multipurpose theatre, a shoebox-shaped concert hall and an auditorium. The hall settings with and without the acoustic shell were both measured. Dual channel dummy head was used as receiver, while a Omni-directional sound source with room acoustics DlRAC were used for MLS production and computing. Measurement points were located throughout the halls, around four to five seats apart. In this paper, the number of reflections at each measurement point is evaluated and compared so as to find out if its balcony has produced additional reflections to any area. The measured energy ratios and other parameters are also compared to find out the effects from the balcony. Furthermore, computer simulations of one of the halls, with and without the balcony, are also done for comparison.