Scale Studies o! Reverberation in Large Coupled Spaces

Abstract

Reverberation times over a wide frequency range have been measured in St. Peter's Basilica in Rome and in St. Mary Queen of the Earth Cathedral in Montreal. The latter is built to a linear half-scale of St. Peter's in its basic architecture which makes possible important comparisons with acoustical theory. However, the decorations, especially the sculpture, are much less extensive in the Montreal church, and furthermore, St. Peter's has more side chapels with openings to act as sound absorbers and coupled air volumes. As a consequence the reverberation times do not scale in the simple ratio as originally anticipated, for the midfrequency reverberation time in St. Peter's is 7.1 sec while that in the Montreal church is 5.9 sec. However, a comparative analysis of the data is important for understanding the influence of coupled air volumes on reverberation and the propagation of sound in large rooms of complex shape. The results are consistent with those previously reported for the four Patriarchal Basilicas in Rome and with measurements in other large churches.