Design of a circular hall improving the subjective preference at each seat

Abstract

The circular type of the medium-sized (400 seats) multipurpose event hall in Kobe Fashion Plaza, which was named Orvis Hall, was designed based on Ando’s theory of subjective preference. Acoustic problems caused by such a circular plan were minimized by means of ceiling diffusion panels, side-wall-reflective panels, and a small room at the back wall preventing echo-disturbance created by the long-path echo or ‘‘Whispering Gallery’’ effects. One of the most remarkable systems of this hall is controlling the subsequent reverberation time through blending architectural acoustics and electrical acoustics by use of a hybrid system with both a reverberation control room and a digital reverberator. Therefore the total scale value of subjective preference at each seat is maximized by the four acoustic factors, namely, the delay time of first reflection, the listening level, the subsequent reverberation time, and the IACC. After construction of this hall, four factors at each seat were measured, and results are presented.