This document summarizes research on simulating the acoustics of the Serbian Orthodox Church Lazarica built in 1375-1377. Researchers took acoustic measurements at 8 positions and used simulation software to model the church. By comparing simulated and measured values for parameters like speech transmission index and reverberation time, they found a high degree of matching, showing the simulation can accurately model the church's acoustics. This allows investigating acoustics anywhere in the church and simulating other similar churches.

1. RESEARCH POSTER PRESENTATION DESIGN ©
2011
www.PosterPresentation
s.com
The 3rd International Conference TAKTONS – Novi Sad, 18-21.11.2015.
Radio Television of Vojvodina and TAKTONS, Faculty of Technical Sciences, University of Novi Sad, Serbian AES section and Dirigent Acoustics
Acoustic Simulation of the Serbian
Orthodox Church Lazarica
ABSTRACT
OBJECTIVES
RESULTS
ACKNOWLEDGEMENT
DESCRIPTION
Fig. 1. Serbian Orthodox Church Lazarica in Real Life
This paper is the result of scientific research on the project of Faculty of Chemistry
University of Belgrade, Theory and practice of science in society: multidisciplinary,
educational, and intergenerational perspectives, project number 179048, financed by
Ministry of Education, Science and Technological Development Republic of Serbia.
Main listening area in orthodox churches is defined in less detail than in performing
spaces. Therefore, receiver positions are chosen to equally cover surface of the
listening area. Total of eight measuring position were used. Sound source are
corresponding to the typical positions of the priest during the liturgy. EASERA was
used for the acoustical measurements of impulse responses, and the church is
modeled in acoustic simulation software EASE. Measured room-acoustical parameters
are compared with those obtained in simulation model (using AURA Ray Tracing).
Figure 2 shows the modelled Serbian Orthodox Church Lazarica.
By comparing the simulated STI values which are derived from the impulse responses
acquired at each position using the AURA Ray Tracing method with the measured STI
values, a great deal of similarity was found. Also, high degree of matching between
the measured and the simulated RT30 (averaged values) was obtained. It is possible to
show overlapping between other acoustical parameters, which make simulation
accurate and beneficial. By obtaining a good simulation model, it is possible to
investigate acoustical parameters in every point inside the church. This is a big
advantage since number of measuring points in a real measurements are limited.
Also, these results confirmed the possibility to model churches that are today found
only in remains, but we have a firm knowledge of their previous architecture.
Moreover, the auralization could be performed in order to demonstrate the prevailing
acoustic conditions in those historical spaces.
Stefan Dimitrijević, The School of Electrical and Computer Engineering of Applied
Studies, Belgrade, Serbia, stefan.dimitrijevic@viser.edu.rs
Zorana Đorđević, Institute for Multidisciplinary Research, University of Belgrade,
Serbia, zoranadjordjevic.arch@gmail.com
Church Lazarica, consecrated to St. Stefan, is an endowment of prince Lazar
Hrebeljanović, built in 1375-1377 as a court church in Kruševac. Lazarica is built in
Moravian architectural style (1371-1459) – the final and the most developed style in
medieval Serbian architecture. The church plan is typical for this period of sacral
building – trikonhos plan with the contractive inscribed cross (16 m x 8,5 m) and one
centrally positioned dome (17,5 m high), suported with the system of arches and
pendentives. All three apses are five-sided on the outside and rounded on the inside.
The floor is made of stone, the walls are mortared and furniture is wooden (iconostas,
stand for icon, lectern).
HISTORICAL CONTEXT
Since acoustics of medieval sacral edifices is more frequently in the focus of the
researchers in the last two decades, church acoustics is recognized as an important
part of cultural heritage. The present paper deals with acoustic computer simulation
of the Serbian Orthodox Church Lazarica and in particular with comparing measured
room-acoustical parameters and those obtained by calculation in a computer model.
EASERA was used for the acoustical measurements of impulse responses, and the
church is modelled in acoustic simulation software EASE. A high degree of matching
between the measured and the simulated results can be obtained. The difference in
measured acoustical parameters and those obtained by the simulation is due to the
following two reasons: the absorption coefficients of the model might differ slightly
from the real absorption coefficients in the church, and the running EASE algorithm
based on statistical particle acoustics has its limitations at the lower frequencies.
CONTACT
Stefan Dimitrijević, Zorana Đorđević
REFERENCES
[1] F. Martellotta, E. Cirillo, P. Ricciardi, “Guidelines for Acoustical Measurements in
Churches,” Appl. Acoust. 70 (2009) 378-388.
[2] Wasim Orfali, Wolfgang Ahnert, “Acoustical Simulation and Auralization in
Mosques,” AES 118th Convention, May, 2005.
Fig. 3. Comparing the Simulated STI with the Calculated STI in the Serbian Orthodox Church Lazarica
Fig. 4. Comparing Measured and Simulated Reverberation Time T30
Fig. 2. The Modelled Serbian Orthodox Church Lazarica as Configured in EASE
CONCLUSIONSDegree of matching between the measured and the simulated results was
investigated. By obtaining a good simulation model, it is possible to investigate
acoustical parameters in every point inside the church and to model a lot of other
churches of the same style with certain accuracy.