Validation and application of three-dimensional auralisation during concert hall renovation

Abstract

During the renovation of auditoria and concert halls, the acoustic quality is normally evaluated from measurements of impulse responses. One possibility for evaluating the acoustic quality from the measurements (the simulations) consists of convolving anechoic music with the measured (or simulated) impulse responses. In this way, a psycho-acoustic test is achieved using a virtual sound field representation. The listening room ‘Arlecchino’ at the University of Bologna includes ambisonics (up to fifth order) and stereo-dipole playback for virtual reproduction of sound in rooms. In this article, the effectiveness of the listening room ‘Arlecchino’ is first analysed, comparing acoustic parameters obtained from binaural impulse responses measured in some opera houses (in Italy) and auditorium (in Japan) with those virtually measured after the virtual reconstruction obtained in the listening rooms. The similarity between real and virtual sound fields, has been evaluated by comparing different acoustic parameters calculated by real and virtual sound fields, in four halls in different configurations, by means of the stereo-dipole method. In the second part of the article, the listening room was used to analyse the variation in interaural cross-correlation measurements in rooms obtained considering different anechoic sound signals convolved with the binaural impulse responses, to quantify the variation of the interaural cross correlation with different motifs. For this purpose, two different musical instrument digital interface musical motifs, very different from each other for their music characteristics, have been considered. Moreover, for each musical motif, different sound characteristics (i.e. different musical instruments) were considered, to consider both the rhythmic and timbre aspect.

The sound diffusion in Italian Opera Houses: Some examples

“…Nevertheless, diffuse-field theory still represents an important way to understand sound propagation in enclosed spaces. In further measurements conducted recently, 12 this non-uniform distribution of soundfield was also resulted depending on sound focalization, which increases this inhomogeneity, especially in the stalls in Opera houses, even more, when moving the position of the sound source.…”

“…This effect was known since the Renaissance period and confirmed in several recent papers. 12 The theatre 'Comunale' in Bologna is one of the most remarkable opera houses existing in Italy, which has been extensively studied for its acoustics. The theatre was designed by the architect Antonio Galli Bibiena, a component of the well-known theatre architects dynasty, and it was inaugurated in 1763.…”

Auralization of Concert Halls for Touristic Purposes

“…Auralization describes the process of rendering audio within a sound field in a way that simulates the binaural listening experience at any position in the 3D environment [7]. Its main goal is the recreation of acoustic characteristics of an indoor or outdoor space [12]. Source materials and room geometry will influence how audio will be filtered within the environment.…”