The effects of source directivity on seats surrounding the platform in recital halls

The influence of source directivity can be significant for chamber music performances, particularly for arena type halls that have improved visual perception to create stronger feelings of intimacy with the audience. The aim of this study was to analyze the effect of source directivity in a recital hall with seats surrounding the stage platform. The effects of room form, source type and orientation, and surface treatment were evaluated based on acoustical simulations using CATT software that accounted for source directivity and surface treatments. The room volume was set to approximately 4000 m3. Most of the acoustical parameters derived from a baritone singer revealed only one factor that can be best represented by 2-k Hz early strength factor GE. Whilst the influence of length-to-width proportion on the distribution of 2-kHz GE from a front facing baritone singer was little, the acoustical energy behind a 45° turned singer was prominently reduced when the room width was increased from 17 m to 22.6 m. The problem could be resolved by limiting the width of the platform as well as splaying the side boxes towards the platform. The energy loss can be compensated for by placing a reflective surface 6-m in front of the platform and additional improvement can be achieved by changing the ceiling to pyramid shape.