Byzantine Churches in Albania: How Geometry and Architectural Composition Influence the Acoustics

The Byzantine churches built between the 7th and the 15th centuries represent an architectural typology that has been developed along with other architectural styles. The evolution of the interior organization, to be composed of only a single nave for the oldest architecture and then developed with additional lateral naves, is one of the multiple aspects that characterizes this building type, studied mainly from an architectural perspective. The variety of roof morphology, being flat, double slope, vaulted or domed, contributes to determining the overall acoustics. This paper deals with the analysis of the acoustic characteristics related to five Byzantine churches located in Albania, specifically in Berat and Cete. A comparison of the impulse response (IR) measured inside each church was given by analyzing the most appropriate acoustic parameters and in line with ISO 3382. The acoustic surveys were undertaken with a minimal furniture and without any audience. The results highlight small difficulties in terms of speech understanding, especially under a speech clarity index found to be below the optimal range limit. This shortfall is attributed to the geometry of the volumes and to the reflecting materials applied to the surfaces that facilitate the build-up of sound energy.