Acoustic evaluation of a contemporary church based on in situ measurements of reverberation time, definition, and computer-predicted speech transmission index

Abstract

An acoustic survey was conducted in a church with a modern architectural style in Curitiba, southern Brazil. The investigation used acoustic measurement methods to assess the acoustic quality of the nave and the results were compared with the NBR 12179 Brazilian National Standard, ISO 3382-1 international standard and IEC 60268-16 Standard. Integrated impulse responses were measured to determine two acoustic objective parameters: (1) Reverberation Time (RT), (2) Definition ( D 50) according to the international ISO/3382 and ISO/3382-1 standards. The Speech Transmission Index (STI) inside the church was calculated by computer simulation. The measured and calculated values were consistent with those proposed by the standards for speech auditoria (RT 500Hz = 1.18 s, D 50 > 50% and STI > 0.45), and are in line with the music and speech intelligibility requirements resulting from the Second Ecumenical Council of the Vatican in 1965, whose liturgical reforms involved the adoption of vernacular languages in place of Latin for religious service.