This article was automatically translated from the original Turkish version.
Süleymaniye Camii was constructed in the 16th century by Mimar Sinan. It is a structure of notable architectural and acoustic significance. The baked clay cubes placed within the dome serve an effective function by preventing sound from concentrating at a single point and balancing low frequencies. Sinan’s architecture presents itself not merely as an aesthetic achievement but as a holistic approach that also appeals to the ear.
Süleymaniye Camii (pexels)
The acoustic character of Süleymaniye Camii is directly linked to its architectural form. The central dome rises 26.2 metres in diameter and 49.5 metres in height, supported by four massive piers. The dome’s geometry, along with its pendentives, muqarnas transitions, side exedras (for those unfamiliar, small subsidiary domes added beside the half-domes—a kind of quarter dome), and half-domes, are the primary elements determining how sound moves and disperses within the space. This structure creates an immersive atmosphere characterized by prolonged reverberation during divine recitations and Quranic chanting.
The acoustic design is also informed by the materials used. Stone and brick surfaces provide hard reflective planes, while lime plasters reinforced with hemp increase sound absorption in the mid-frequency range. Carpets and the woven reed layers beneath them contribute to sound absorption at floor level. The baked clay cubes inserted into the dome behave like Helmholtz resonators—acoustic devices consisting of a hollow cavity with a narrow opening—thereby controlling the buildup of low-frequency sound.
The perforated surfaces of wooden railings in the mahfil (a designated area for the caliph or sultan) and the niches with muqarnas details support sound diffusion, aiming to achieve a homogeneous acoustic perception across different points within the space. However, repairs carried out in subsequent centuries introduced different types of plaster and sealed off resonators, disrupting this delicate balance and contributing to the excessively long reverberation times observed in modern measurements.
Süleymaniye Camii Interior (flickr)
The mosque’s acoustics have been significantly altered by centuries of repairs. During the 19th-century renovations by the Fossati brothers—who were also commissioned by Sultan Abdülmecid to restore Hagia Sophia—the openings of the baked clay cubes (sebular) in the dome were sealed, and plaster replaced the original hemp-reinforced lime mortar. These interventions led to prolonged reverberation in low frequencies and an uneven distribution of sound.
In the 20th century, cement-based plasters further worsened the problem by reducing sound absorption. Between 2007 and 2011, another restoration was undertaken. During this project, the cement plasters were removed and replaced with lime-hemp mortars. The openings of the sebular were reopened, and Sinan’s original acoustic system was revived.
Modern interventions have also introduced some unintended effects. Newly installed electrical panels and mechanical systems generate background noise that reduces speech intelligibility. Consequently, restoration efforts have clearly demonstrated that preserving not only visual integrity but also acoustic heritage is essential.
Architectural Form and Acoustics
The Impact of Restorations
