Analysis and Acoustic Correction of a Contemporary Italian Church

Nowadays, architects and designers build new churches primarily considering the architectural shape to emphasize the iconographic message without sufficiently investigating the acoustic climate. In many cases, designers propose elliptical or irregular geometries for the shapes of these buildings and, in addition, the furniture of indoor surfaces have unsuitable absorption and diffusivity coefficients. Thereby, it can be observed the arise of serious acoustical problems such as standing waves, flutter echo, sound focusing and intensive late reflections (greater than 100 ms) which seriously decrease speech intelligibility and diminish the effectiveness of the early sound energy. This paper presents the results of an acoustic survey on the Catholic Church “Invaluable Blood of Jesus”, situated in Ragusa (Italy), which is characterized by many problems mentioned above. During last years, some refurbishment interventions have attempted to reduce the acoustic discomfort, but an uncorrected approach has completely compromised the speech intelligibility, especially during liturgical functions. Recently, the authors have been involved to propose suitable interventions for improving the acoustic quality of this environment. Preliminarily, a measurement survey was conducted to evaluate the main acoustic indices ( RT 60 , STI , EDT , C 80 , D 5 0 ) and portray the current acoustic climate. After that, it was developed an acoustic computer simulation on a 3D model of the church, in order to calibrate the model comparing measured and simulated data. This procedure allowed testing the reliability and accuracy of the model. Finally, We propose two different interventions of acoustic correction. Globally it is possible to obtain an improvement of RT 60 from 7.3 to 2.5 s at 1 kHz and STI increases from 33% to 40%, at 1000 Hz.