The Acoustic Characteristics of the "Dives in Misericordia" Church

This paper discusses the acoustic characteristics of the "Dives in Misericordia" Church in Rome. The church was designed by architect Richard Meier and opened in 2003. It was made entirely of white concrete and consists of three septa with a double curve shaped like a sail; with the highest one measuring about 26 m. The nave roof is glass. The volume is approximately 14.000 cubic meters, the width of the nave is 19.5 m, while the maximum width is 29.5 m. The internal length is 32.0 m, while the total length is 45.6 m. It can seat approximately 240 people. The measurements of the acoustic characteristics were carried out using an impulsive sound source, while the impulse responses were acquired with a digital recorder and processed. The acoustic measurements were taken by placing a microphone at different points of the nave (the area occupied by the congregation), with the sound source being placed on the altar. It was therefore possible to obtain a spatial distribution of the average acoustic characteristics inside the church. At a frequency of 1000 Hz, the average values of T30 was about 10 seconds, while D50 was about 0.2; STI was about 0.2. In its current configuration, the church is neither suitable for understanding speech or listening to music. A 3D virtual model was created and with the help of the building acoustics software, Odeon, it was possible to study the sound field inside the church. The possibility to carry out an appropriate acoustic correction was analyzed, in order to reduce the values of the reverberation time as well as increase the D50 and STI, by pacing on a side wall of the church an adequate number sound-absorbing polyester panels.