Room acoustic design of multipurpose auditoria in Japan

Abstract

Japan is divided into 47 administrative districts, i.e., prefectures (including the Tokyo Metropolitan Area), containing a total of about 670 cities. Most of the prefectures and over half the cities have public halls, which are playing an important role as community cultural centers, and about 20 new halls are being constructed annually on an average. Most of these halls are designed as multipurpose auditoria, from the viewpoint of greatest efficiency and versatility of use. Most are 8000–15 000 m3 a in size with a seating capacity of 800–2000. As to the architectural and acoustical conditions of these halls, many objective and subjective studies have been carried out by research groups, with our laboratories playing a central role. The reverberation times of many good halls have been found to lie close to or slightly below the Knudsen and Harris's optimum value. The new halls have been designed in accordance with these results. A distinctive architectural feature of these halls is their wide variety of facilities, including movable stage sound reflectors for concerts, settings for stage performances, etc. Recently, a considerable number of halls have been designed to be adapted for different types of presentation by adopting variable reverberation units, a movable proscenium, variable room volume facilities, and movable partition walls.