ryan bessey
left: Kucuk Ayasofya Mosque, originally the Church of Saints Sergius and Bacchus, 527-536. above: the model of the church taken from ODEON example files
wikipedia file 20101222: user:Ggia
acoustic analysis Parking garages commonly have many hard surfaces – mostly concrete but also metal and glass from the cars. This is similar to traditional churches which are usually stone, brick, wood and glass. To compare the reverberation time of the parking garage and a church, we used ODEON room acoustic modelling software, used by acoustical engineers to simulate the interior acoustics of buildings. The means of calculation is a combination of ray-tracing (the path of sound waves are traced as if they were simple rays of light) and an image-source method (reflections resulting in the creation of a new virtual source as if each surface was a mirror). The required inputs to an ODEON model are room geometry, which can be imported from SketchUp, and surface materials whose acoustical properties have been measured. With this information, the acoustics of a space can be predicted, analysed and even listened to through auralisation. These models can give designers a very good sense of a space’s acoustics even before it is constructed. For this exercise, the parking garage was drawn in SketchUp and imported into ODEON, whereas the church model is one of the examples that comes with the ODEON software, and wasn’t generated by us. The result of our analysis was that both spaces have long reverberation times, which is their primary shared acoustical characteristic. While this is likely coincidental in terms of the parking garage, in churches the effect of reverberation is purposely sought to emphasise specific types of music. Domes and arched ceilings can focus reflections and slow down temporal changes common with instruments such as singing voices, pipe organs and stringed instruments. These musical instruments are often synchronised with the reverberation characteristics of the space to support specific liturgical acoustic effects.
Accounting for the acoustic similarities between the garage and the church made me wonder what the acoustic properties of a sacred space are. Some of the earliest sacred architecture that we know is found in caves in southern France. Paleo-anthropologists have often pondered the distribution of paintings within these caves – they are not placed on the best quality wall surface for painting: many are compressed in small areas and on uneven and difficult to paint surfaces. Iegor Reznikoff, an acoustics expert at the University of Paris, conducted research into the caves at Niaux, concluding that ‘In the cave of Niaux in Ariège, most of the remarkable paintings are situated in the resonant Salon Noir, which sounds like a Romanesque chapel’, an observation with support in the academic world from researchers such as Paul Pettitt (Paleolithic Archaeology, University of Sheffield) and Steven Errede (Acoustical Physics, University of Illinois, Champagne-Urbana). 1 Paintings are placed in the parts of the cave with acoustic properties that amplify the human voice and where songs and chants can linger. In other words, spaces with long reverberation times are attractive to humans when we are creating environments of religious experience. Throughout religious history caves have featured as places to commune with the spiritual world. Sybil’s cave in Cumae is but one example from the European tradition. Do the spirits and gods sound more resonant and powerful in these acoustic environments? If caves are not readily available, do we recreate the cave in our religious architecture? I don’t believe it is an accident that caves and religious architecture share the same reverberation time. The religious voice and the associated power of chanting are magnified by a long reverberation time in mosques and churches.
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