Acoustic control in octagonal geometry: case study of the ‘Torri dell’acqua’ auditorium

The acoustic design of an octagonal hall is briefly resumed in this work. Some hypothesis on the modal characteristics of the hall have been proposed, Following these hypotheses, a system of asymmetrical suspended reflectors has been installed to allow the modal control and to optimize the early reflections. The acoustic design of the hall, permitted to get: - EDT and C80 - high diffuseness of the sound field; values adequate to the intended use of the hall; - quite constant values of the sound energy in the seat areas and high sound pressure levels; - a certain degree of variable acoustics to agree with the request of performers. Ando’s subjective preference functions have been also calculated for different sound signals, represented by their (τe)min values.