Acoustical design of the opera house of the New National Theater, Tokyo, Japan

Abstract

The New National Theater (NNT) project containing three halls started with an open international design competition in 1986 and ended with a grand opening October 10, 1997. The architect is Takahiko Yanagisawa. The opera house, the core of the NNT facility, has a seating capacity of 1810, a volume of 14 500 m3, and a reverberation time with full audience of 1.5 s (stage curtain open). Various model experiments, using a CAD model, 1:10 scale model, and full-sized materials samples, were conducted over a 7-year period. As a result, the main floor has an almost rectangular shape, three-layered balconies have a modest fan shape, and the balcony fronts at each level create a rectangular shape. The overhang of each balcony is minimized to take visibility requirements into consideration. The unique design has a large curved reflector in front of the proscenium and over the orchestra pit and curved reflecting surfaces at the fronts of each of the side balconies to reflect the singer’s voices uniformly from a large portion of the tremendous stage. The balcony fronts, the side walls, and the ceiling also augment the reflections from those surfaces. The unoccupied values are: EDT=1.6 s, C80(3)=2.4 dB, [I−IACCE3]=0.66m and bass ratio=1.1.