Browsing by Subject "Mosque acoustics"

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Open Access
The acoustical characteristics of the Kocatepe Mosque in Ankara, Turkey
(Taylor & Francis, 2008) Sü, Z.; Yilmazer, S.
This research investigates the acoustical characteristics of mosques of the classical Ottoman period and the contemporary period. Kocatepe Mosque, the major mosque in Ankara, Turkey, as a case from the contemporary era is a unique combination of 16th century Ottoman aesthetics and 20th century technology. Although previous and recent mosques have been inspired by this combination, the use of a reinforced concrete dome without cavity resonators could cause long reverberation times especially in low frequencies. The purpose of this study was to investigate this condition by studying Kocatepe Mosque. The acoustical characteristics of the mosque were analyzed by computer simulation. Objective room-acoustic indicators including reverberation time (RT), early decay time (EDT), clarity (C80), definition (D50), lateral fraction (LF), speech transmission index (STI) and strength (G) are presented. The results show that the acoustical quality of Kocatepe Mosque is not optimal when it is empty, and closest to optimal conditions when fully occupied. The new techniques to overcome excessive low frequency attenuation caused by huge concrete shells of today's mosques are discussed in conclusion.
Open Access
Acoustical characterization of clay pots in Ottoman architecture through experimental and numerical analysis methods
(2022-07) Atay, Gülnihan
Employment of clay pots as building elements is a common practice especially in the medieval structures throughout Europe and Near East. Despite the fact that their acoustical employment in historic structures is well known and dates back to the 1st century BC as observed in Vitruvius' writings, their true contribution to the acoustics of Medieval Architecture remains to be a subject of discussion. They are also present in Ottoman Architecture including Süleymaniye Mosque designed by Sinan the Architect Laureate. Although these elements placed in the dome of Süleymaniye are often interpreted to be utilized as Helmholtz resonators, a scientific account regarding their sound-absorption performance is needed so as to understand whether they actually perform as cavity resonators. Therefore, the scientific investigation of their acoustical behaviour through analytical, experimental, and numerical analysis methods is necessitated. The objective of this study is to discuss the effects of the clay pots on the sound energy decay pattern of Süleymaniye Mosque. The study begins with an archival research phase covering the versatile employments of clay pots as building elements that are not limited to their acoustical utilization. The study then proceeds with the impedance tube measurements conducted with the reproduced sample of an actual-sized clay pot employed in the structure. The results are then verified with finite element modelling (FEM) simulations. Finally, sound absorption coefficients, obtained from the latter are transferred into the ray tracing simulations so as to understand the pots' effect on reverberation times (T30) in the edifice. In the conclusion part, sound absorption performance of clay pots and their possible contribution to the mosque acoustics are discussed. As a result of the study, the resonance frequency of the clay pots embedded into the central dome of Süleymaniye Mosque is found to be 50 Hz. Additionally, they are also proven to be effective at 500 Hz octave band. Consequently, the ray tracing simulations exhibit a 2 seconds decrease in T30 values at 500 Hz octave band. This also proves the improvement of reverberation time at this octave band range, which was measured after the final restorations of Süleymaniye Mosque with repaired pots.