Virtual acoustic reconstruction of the church of Gesú in Rome: a comparison between different design options

The church of the Gesú in Rome was built as an example of how Counterreformation churches had to be according to the Jesuit order. Among the aspects taken into account, acoustics played a significant role, because preaching was one of the key points of the Jesuit order and, at the same time, the Council of Trent had emphasized the didactic role of the liturgical singing, based on clearly understandable words. During the building of the church a dispute arose as to which was the best way to cover the church in order to get suitable acoustic conditions. Cardinal Farnese (who paid for the church) preferred a barrel vault, while Jesuits seemed to prefer the flat coffered ceiling. In the end, the barrel vault was preferred to the flat coffered ceiling, but was it the right choice? Taking advantage of an on-site measurement campaign, a virtual acoustic model of the church was created and properly calibrated. Then, using the same surface characteristics a set of modified models with a flat coffered ceiling in place of the barrel vault was created. Different ceiling heights were considered, affecting both volume (and hence reverberation time) and delay of early reflections. A point-by-point comparison was finally carried out in order to analyze the effects that the different geometric configurations had on the acoustic parameters. Different sound sources, including human voice directivity patterns, were used in different positions in order to explore in detail the effects of the different covering options. Results suggest that it was ceiling height rather than its shape that could have made a difference on acoustic behaviour.