Abstract
The article presents modified global assessment indices, developed in previous studies, for measuring the acoustic quality of Roman Catholic churches: the four-parameter Gap index and the Gi index based on five acoustic parameters. The replacement of RASTI, previously used in the acoustic assessment of churches, with STI has broadened the scope of church assessment and contributed to an improvement in the accuracy of the proposed method. Verification of new calculation procedures was performed on the 12 churches included in the calculation model and, additionally, on another church.