Acoustic effectiveness of pulpit reflector in churches

Abstract

Since the 12th century, pulpits and pulpit reflectors (canopies) were widely used in churches. This paper studies the acoustic effectiveness of such devices based on in site measurements (STI and D50) in four (unoccupied) churches with pulpits with and without the canopy. The pulpit reflector can remove the late reflection resulting from a high ceiling and makes possible to improve the listening conditions at medium distance from the pulpit. The pulpit reflector effectiveness decreases and becomes even unfavourable when the height of the ceiling drops (h < 10 m) and when the distance to the speaker increases. The absolute variations of speech intelligibility ratings are generally rather weak (average STI variation from +0.01 to -0.03), but can increase in the presence of an assembly.