An Investigation on the Effects of Architectural Features on Acoustical Environment of Historical Mosques

acoustics

Article An Investigation on the Effects of Architectural Features on Acoustical Environment of Historical Mosques

Fatma Yelkenci Sert * and Özgül Yılmaz Karaman *

Faculty of Architecture, Dokuz Eylül University, Buca, Izmir 35390, Turkey * Correspondence: [email protected] (F.Y.S.); [email protected] (Ö.Y.K.)

Abstract: In the historical period, different mosques were built in the Anatolian side; the differences in size, typology and style were affected by the climate conditions, cultural and social aspects, availability of materials and the construction techniques of the region they were built in. The ceiling structure, which is the most influencing factor for mosque acoustics, is designed with either curvilinear elements or a flat ceiling for mosques. In the context of our case study, the eight historical mosques in Turkey, with different materials and types of ceiling structures, are investigated in terms of acoustical characteristics in the main prayer hall. Acoustical data are collected by measurements to reveal how the formal differences and material change in ceiling structures affect the acoustic environments of mosques with similar volume. Distribution of acoustical parameters and the suitabil- ity of the values obtained through measurements are compared to reflect the effect of architectural features on the acoustical characteristics of the prayer hall.

Keywords: room acoustics; historical mosques; acoustical parameters

Citation: Sert, F.Y.; Karaman, Ö.Y. 1. Introduction An Investigation on the Effects of Architectural Features on Acoustical Worship buildings have been important in communities throughout the history, be- Environment of Historical Mosques. cause they are the manifestation of religions and beliefs in a society. Religious structures Acoustics 2021, 3, 559–580. https:// are also iconic examples of architectural history and, on the urban scale, they enrich the doi.org/10.3390/acoustics3030036 cities with their size and decoration, not to mention the architectural elements such as domes and minarets. They also help to impress the community with their interior spaces, Academic Editor: Francesco Aletta and it can be stated that the acoustical perception affects the prayers even more than the visual perception, in terms of experiencing the space and the divine feeling during religious Received: 12 July 2021 rituals [1]. Accepted: 5 August 2021 Historical buildings, especially historical worship spaces have been also evaluated for Published: 7 August 2021 their acoustical ambiance in the literature. Most of the time “archaeoacacoustic” analysis of prayer halls is carried out by measurements and simulations [2]. Effects of the architectural Publisher’s Note: MDPI stays neutral styles on historical buildings are also investigated, especially for the churches [3–5]. with regard to jurisdictional claims in Mosques contain worship rituals as a worship place for Muslim people. Expectation published maps and institutional afﬁl- of the occupants varies depending on the needs of the ritual. For example, individuality is iations. needed for praying, while a sense of unity is needed during the recitation of the Quran or hymns. The activities that take place in the prayer hall can be listed as; praying individually or with an Imam to hear prayer’s order, listening to the Imam’s speech on Fridays, and listening to the musical type of Holy Quran. Praying rituals need a high level of speech Copyright: © 2021 by the authors. intelligibility; however, sometimes musical rituals need a more (reverberant) environment. Licensee MDPI, Basel, Switzerland. Additionally, most of the time, the prayer hall is expected to make people feel close to This article is an open access article God. These different uses also need different acoustical requirements. To create the desired distributed under the terms and feeling in the space at the required time, rooms should be evaluated in terms of acoustical conditions of the Creative Commons conditions. All these activities require a high level of speech audibility and intelligibility. Attribution (CC BY) license (https:// The main prayer hall consists of different building elements to maintain the activities that creativecommons.org/licenses/by/ are listed above; such as the “mihrab”, “mimbar”, and “muezzin gallery”. Khutba is read 4.0/).

Acoustics 2021, 3, 559–580. https://doi.org/10.3390/acoustics3030036 https://www.mdpi.com/journal/acoustics Acoustics 2021, 3 560

on the mimbar located on the right side of the mihrab. The mimbar provides the visual connection between listener and speaker because it includes steps. In addition to this, for the speaker on the steps in the mimbar during the Khutba and sermon, speaking provides a positive impact on acoustic conditions. The muezzin gallery is made for the muezzins to sit on the high platform, give the “tesbihat” sounds, and repeat what the imam is saying. This situation helps to keep the sound source over the audience and to stabilize the sound energy in the volume [6]. In the mosques, the feeling of individuality is desired in praying, and the feeling of unity is desired in the reading of the Holy Quran, and hymns, etc. Therefore, mosques are places that include both speech and music. However, instrumental music does not take place in mosques because it is not mentioned in the Holy Quran. In functional terms, speech and its intelligibility are the major acoustical considerations in the acoustical design of a mosque. There is a significant relationship between the cultural heritage building and its acoustics [7]. Oleg Grabar, one of the leading Islamic art historians, says that the self- representation of Islamic culture is based on hearing more than seeing [8]. Ergin’s study indicates that Ottoman architects see mosques as where the original revelation is restaged, and they are musical instruments that provide the voices of the Quran [9]. For these reasons, those historical examples are important subjects of studies on archaeoacoustics. On the other hand, there are many different historical mosques all over the world, with differences are in terms of architectural features and variety of used materials within the interior space. This variation in mosque architecture complicates the acoustical evaluation process. In addition to this, there is a lack of certain evaluation criteria or defined optimum parameter ranges which are written/published as standards for mosque acoustics. There are some studies in the literature about acoustical requirements and evaluation parameters for mosques. In this study, the methods, and parameters, which have been used in recent studies, are investigated, as are the similar methods and parameters for the assessment and evaluation of mosque structures. Most of the time, existing recommendations, which are developed for the speech auditoriums or dramatic theatres, have to be used to evaluate the acoustic quality of the mosques. In other words, unlike auditoriums, there are no defined recommendations or rules for the acoustical parameters inside mosques. However, regarding mosques, the elaboration of general sound parameters requires a specific understanding of the acoustical and spiritual environment expected in such structures. In some studies, there have been some recommendations developed for the acoustical parameters by considering the activities in mosques [10,11]. To show the sacredness of religion, historical mosques were often built in large volumes by using high and wide dome structures [12]. Acoustical problems due to the large volumes are expected in these mosques, as with large cathedrals [13]. However, some ways of preventing this problem were considered. For example, the floors of mosques are covered by carpets, which are made of absorptive material, providing acoustic comfort. By using sound absorbent surfaces, most of the sound energy cannot be reflected, which prevents long reverberation times. In Sinan mosques, the mimbar and muezzin gallery are made by using perforated panels, which reduce the sound energy level and provide acoustic comfort [14]. The acoustical quality of the mosques has been discussed in the literature, and studies have mostly focused on the analysis of the ancient and/or contemporary examples of the mosque architecture. Such studies may include single mosque cases [15–18], or some of them include comparisons of mosques to other mosques [14,19–24] or comparisons of mosques to other worship spaces (churches and/or synagogues) [25]. This article aims to investigate the objective parameters of the sound of the main prayer hall of eight historical mosques from the Western part of Anatolia. The acoustical evaluation of these historical examples and a comparison of the results with a classification are objectives of the paper. As a result of the analyses, it has emerged that the acoustic parameters alone are not sufficient in the evaluation of the mosques and that the acoustic parameters should be considered as a whole with the architectural features of the volumes. Acoustics 2021, 4 FOR PEER REVIEW 3

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parameters should be considered as a whole with the architectural features of the vol- Itumes. is seen It that is seen the acousticthat the environments acoustic environments of mosques of with mosques domed with masonry domed and masonry completely and woodencompletely ceilings wooden are quite ceilings different. are quite different.

2.2. Method Method and and Scope Scope of of the the Study Study Masonry-domedMasonry-domed mosquesmosques withwith largelarge volumes volumes have have been been the the subject subject of of most most of of the the studiesstudies in in the the ﬁeld field of of architecture. architecture. Smaller Smaller ones ones with with wooden wooden or masonry or masonry ceiling ceiling structures struc- aretures mostly are mostly not included not included in these in these studies, studies, although although the the number number of of them them is is more more than than monumentalmonumental mosques.mosques. Within the the scope scope of of this this study, study, the the aim aim is istoto focus focus on on smaller smaller ex- examplesamples of of mosques mosques in in the the Aegean Aegean Region Region of of Turkey Turkey and and to to evaluate evaluate them them in in terms terms of ofacoustical acoustical ambiance ambiance of ofprayer prayer hall hall under under a classification. a classiﬁcation. With With some some studies studies in the in litera- the literature,ture, it is concluded it is concluded that thathistorical historical mosques mosques with withlarge large volumes volumes work work as a coupling as a coupling space spaceand differ and differ from fromsmall-sized small-sized mosques mosques with withthese these features features [12]. [Small-sized12]. Small-sized mosques mosques in the 3 inrange the rangeof 1000–2000 of 1000–2000 m3, which m , are which found are in found large innumbers large numbers in Western in Anatolia, Western Anatolia,constitute constitutethe case group the case of groupthe study, of the since study, they since diff theyer from differ large from volume large volumemosques mosques in terms in of termsacoustic of acoustic perception. perception. InIn Figure Figure1, volumes1, volumes and measuredand measured and/or and/ simulatedor simulated T30 values T30 of values historical of mosqueshistorical thatmosques are gathered that are fromgathered the literaturefrom the literature review during review the during study the are study shown arewith shown the with mean the valuesmean values of T30 valuesof T30 values of the casesof the [cases21,22 ,[21,26–22,26–31].31]. It also It represents also represents a summarized a summarized version ver- ofsion the of literature the literature and documentationand documentation of historical of historical mosques mosques that that are are evaluated evaluated in in terms terms of acoustics. of acoustics.

Figure 1. The T30 values of mosques in the literature and present study. Figure 1. The T30 values of mosques in the literature and present study.

AccordingAccording to to the the graph graph in in Figure Figure1 ,1, there there are are many many historical historical mosques mosques with with a rangea range ofof different different volumes; volumes; mosque mosque volumes volumes in in the the range range of of 1000–2000 1000–2000 m m3 3are are more more numerous numerous thanthan other other examples examples that that studied studied in in the the literature. literature. InIn thisthis study,study, as as a a part part of of the the studies studies evaluatingevaluating the the acoustic acoustic comfort comfort conditions conditions of of mosques mosques built built in in different different historical historical periods periods inin Aegean Aegean Region, Region, we we want want to focusto focus on on the the group group with with volumes volumes of 1000–2000 of 1000–2000 m3. However, m3. How- thereever, is there no material is no material and top and cover top informationcover information of mosques of mosques in Figure in 1Figure. We plan 1. We to makeplan to evaluationsmake evaluations by using by information using information regarding regarding material andmaterial ceiling and structure ceiling ofstructure eight mosques of eight thatmosques represent that allrepresent mosques all in mosques this volume in this range. volume range. However,However, it it is is problematic problematic to to say say that that there there is is a a clear clear relationship relationship between between the the prayer prayer hallhall size size andand thethe T30T30 valuevalue for the mosques; mosques; th thisis brings brings to to light light the the fact fact that that other other archi- ar- chitecturaltectural features features and and materials materials should should be becons consideredidered for fora strict a strict eval evaluation.uation. Starting Starting with with this volume group, it is considered to analyze the effects of elements such as type of ceilings and materials on acoustic conditions. Thus, both wooden covered mosques,

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which are not much subject to studies, will be evaluated by making comparisons and masonry covered mosques are selected as cases for evaluation of acoustic environment. To evaluate the acoustic ambiance, in-situ acoustical measurements was held in eight mosques. Measurements process is described in heading 4. Before that, more detailed architectural and structural features of the cases are described in following section.

3. Architectural Features of Cases Although most of the historical buildings that belong to society are made and remade with a classical typology, mosque structures have been the type of building that has undergone constant changes throughout the historical process. Although they have the same religious rituals, mosques were built in different regions, and because of the various cultures, that is why we find diversity in forms and shapes. Considering the whole of Anatolia, it is seen that mosques were built with both masonry and wooden materials, depending on many factors, such as climate conditions, cultural aspects, social structure and wealth of society as well as the opportunities of construction techniques at the date of construction. In the Aegean Region, it is possible to see almost every size and construction techniques of mosque architecture. Single-domed masonry, multi-domed masonry, single- or multi-domed woodwork (combination of a centrally located lathing dome and side parts with flat ceilings or curvilinear top cover elements such as wooden dome or vault) or mosques with wooden flat ceilings have been built throughout history. An effort has been made to include all the combinations of the roof/ceiling structure in this study. Thus, eight mosques which have different roof configurations, similar volumes and located in the same region are the subjects of the study. Their unique architectural features are briefly described below in separate headings and tables (Tables1–8).

3.1. Lalapa¸saMosque The mosque has a square plan covered by a single masonry dome with a diameter of 9.77 m. The transitions to the dome from the walls are provided by pendentives. The distance from the ﬂoor of the building to the bottom of the pulley is approximately 8.85 m, the height of the pulley, which the dome sits on, is 1.55 m and the height of the dome is 3 m. There is a prayer hall for women, located to the north of the main hall, supported by two wooden posts of square section. The wooden lattice surfaces, which serve as a visual dividing panel between the main prayer hall and the prayer area for women, also act as the railing.

Table 1. The architectural features of Lalapa¸saMosque.

Lalapa¸saMosque Location Manisa Year of construction 1570 System of ceiling Single-domed masonry Plan dimensions 9.84 × 9.93 m Average room height 10.4 m Average room volume 1060 m3 Plan typology Square Capacity 121 Volume per person 8.76 m3

The mihrab, which is in the form of a semicircular niche, is covered with tiles. There is a wooden sermon chair in the southeastern part of the building and a marble mimbar in the west of the mihrab. The ﬂoor is covered with carpet, the dome and walls are covered with plaster and paint (Figure2). The wall surfaces of the mosque are covered with wood up to a height of 1.2 m from the ﬂoor. The building is in a large courtyard surrounded by many trees. Acoustics 2021, 4 FOR PEER REVIEW 5

in the west of the mihrab. The floor is covered with carpet, the dome and walls are covered with plaster and paint (Figure 2). The wall surfaces of the mosque are covered with wood Acoustics 2021, 3 up to a height of 1.2 m from the floor. The building is in a large courtyard surrounded by563 many trees.

FigureFigure 2.2. InteriorInterior viewsviews of main prayer hall and exterior view of Lalapa Lalapa¸saMosqueşa Mosque (photos (photos by by the the authors). authors). ˙ 3.2. İIvazpa¸saMosquevazpaşa Mosque The mosque was built in 1484 in Manisa with a transverse rectangular plan. The mosqueThe ismosque covered was by thebuilt main in 1484 dome in centrallyManisa with and a side transverse aisles covered rectangular by four plan. smaller The domesmosque with is covered a masonry by the system. main Thedome main centrall domey and of the side mosque aisles covered has a diameter by four of smaller 7.85 m (Tabledomes2 ).with The a smaller masonry domes system. have The diameters main dome of 2.53 of the m and mosque 3.23 m, has respectively. a diameter Theof 7.85 walls m have(Table a 2). thickness The smaller of approximately domes have diameters 1.20 m. The of 2.53 transitions m and 3.23 of the m, domesrespectively. are provided The walls by muqarnashave a thickness (Figure of3). approximately The symmetry 1.20 of the m. mosque The transitions plan is destroyed of the domes by the are location provided of theby gravemuqarnas chamber. (Figure 3). The symmetry of the mosque plan is destroyed by the location of the grave chamber. Table 2. The architectural features of Ivazpa¸saMosque.˙ Table 2. The architectural features of İvazpaşa Mosque. Ivazpa¸saMosque˙ İvazpaşa Mosque Location Manisa LocationYear of constructionManisa 1484 Year of constructionSystem of ceiling Multi-domed1484 masonry System ofPlan ceiling dimensions Multi-domed 16.39 masonry× 8.23 m Plan dimensionsAverage room height 16.39 × 8.23 m 10 m Average room volume 1406 m3 Average roomPlan height typology Transverse 10 m rectangular plan Average room Capacityvolume 1406 m3 121 Plan typologyVolume per person Transverse rectangular8.76 m plan3 Capacity 121 3 TheVolume ﬂoor per of theperson mosque is covered with carpet. The 8.76 women’s m area, which is separated from the main hall with curtains, is located to the northeast of the mosque. The muqarnas headedThe mihrab floor of niche the mosque is located is covered on the with south ca wallrpet. and The iswomen’s covered area, by painted which is plaster. separated The Acoustics 2021, 4 FOR PEER REVIEWfrom the main hall with curtains, is located to the northeast of the mosque. The muqarnas 6 mosque is close to the city center, surrounded by trees, a cemetery, less used trafﬁc roads, andheaded residences. mihrab niche is located on the south wall and is covered by painted plaster. The mosque is close to the city center, surrounded by trees, a cemetery, less used traffic roads, and residences.

Figure 3. Main prayer hall and side aisle of Ivaz˙ Pa¸saMosque (photos by the authors). Figure 3. Main prayer hall and side aisle of İvaz Paşa Mosque (photos by the authors).

3.3. Çeşnigir Mosque

The mosque was built in 1474 in Manisa and has a transverse rectangular plan. The mosque is covered with a large dome in the middle and four small domes in the side spaces. The domes are made by a masonry system. The main dome of the mosque has a diameter of 9 m. The smaller domes have diameters of 3.30 m. The side spaces are covered by oval domes supported by pendentives. The walls have a thickness of approximately 1.10 m.

Table 3. The architectural features of Çeşnigir Mosque.

Çeşnigir Mosque Location Manisa Year of construction 1474 System of ceiling Multi-domed masonry Plan dimensions 18 × 9.82 m Average room height 8.2 m Average room volume 1700 m3 Plan typology Transverse rectangular plan Capacity 221 Volume per person 7.69 m3

The sermon chair is made of marble, the mihrab is made of plaster and the mimbar is made of wood (Figure 4). The floor of the mosque is covered with carpet. The east part of the narthex is closed by panels for the prayer hall for women. In the month of Ramadan, the east part of the main worship area is closed with curtains for women. A public park, surrounded by lots of shops and coffee houses, is located at the north and east of the mosque. The mosque is surrounded by dwellings on the south side and a car parking area on the west side of the mosque.

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3.3. Çe¸snigirMosque The mosque was built in 1474 in Manisa and has a transverse rectangular plan. The mosque is covered with a large dome in the middle and four small domes in the side spaces. The domes are made by a masonry system. The main dome of the mosque has a diameter of 9 m. The smaller domes have diameters of 3.30 m. The side spaces are covered by oval domes supported by pendentives. The walls have a thickness of approximately 1.10 m.

Table 3. The architectural features of Çe¸snigirMosque.

Çe¸snigirMosque Location Manisa Year of construction 1474 System of ceiling Multi-domed masonry Plan dimensions 18 × 9.82 m Average room height 8.2 m Average room volume 1700 m3 Plan typology Transverse rectangular plan Capacity 221 Volume per person 7.69 m3

The sermon chair is made of marble, the mihrab is made of plaster and the mimbar is made of wood (Figure4). The ﬂoor of the mosque is covered with carpet. The east part of the narthex is closed by panels for the prayer hall for women. In the month of Ramadan, the east part of the main worship area is closed with curtains for women. A public park, surrounded by lots of shops and coffee houses, is located at the north and Acoustics 2021, 4 FOR PEER REVIEW 7 east of the mosque. The mosque is surrounded by dwellings on the south side and a car parking area on the west side of the mosque.

FigureFigure 4.4. MainMain prayerprayer hallhall andand sideside sectionsection ofof Çe¸snigirMosqueÇeşnigir Mosque (photos(photos byby thethe authors).authors).

3.4.3.4. Attar Ece Mosque TheThe mosque,mosque, whichwhich waswas builtbuilt inin thethe secondsecond halfhalf ofof thethe 14th14th centurycentury inin Manisa,Manisa, waswas damageddamaged inin 1549.1549. It waswas rebuiltrebuilt onon thethe oldold foundationsfoundations ofof thethe buildingbuilding inin 19231923 [[32].32]. TheThe mosquemosque hashas aa rectangularrectangular planplan andand aa ﬂatflat ceilingceiling mademade ofof wood.wood. TheThe planplan dimensionsdimensions areare 9.759.75 ×× 21.521.5 m. m. The The height height of of the the building building is is 7.2 7.2 m. m.

Table 4. The architectural features of Attar Ece Mosque.

Attar Ece Mosque Location Manisa Year of construction 1480 System of ceiling Wooden flat ceiling Plan dimensions 21.5 × 9.75 m Average room height 7.2 m Average room volume 1510 m3 Plan typology Transverse rectangular plan Capacity 263 Volume per person 5.74 m3

The women’s hall is located on the narthex, which is covered with glass surfaces and is separated from the main prayer hall by wooden lattice surfaces. The inner surface of the marble mihrab was covered with tiles. There is a marble mimbar in the west and a sermon chair made using marble in the east of the mihrab. There is a wooden muezzin lodge west of the entrance door. The walls of the mosque are covered with wooden panels up to 1.2 m from the floor. The floor of the building is covered with carpet, and the walls are plastered and painted (Figure 5). The mosque is located near the city center, surrounded by residences, and pedestrian and traffic roads.

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Figure 4. Main prayer hall and side section of Çeşnigir Mosque (photos by the authors).

3.4. Attar Ece Mosque The mosque, which was built in the second half of the 14th century in Manisa, was damaged in 1549. It was rebuilt on the old foundations of the building in 1923 [32]. The Acoustics 2021, 3 mosque has a rectangular plan and a flat ceiling made of wood. The plan dimensions565 are 9.75 × 21.5 m. The height of the building is 7.2 m.

Table 4. The architectural features of Attar Ece Mosque. Table 4. The architectural features of Attar Ece Mosque. Attar Ece Mosque Location Attar Ece Mosque Manisa Year of constructionLocation 1480 Manisa SystemYear of of ceiling construction Wooden flat 1480ceiling System of ceiling Wooden ﬂat ceiling Plan dimensionsPlan dimensions 21.5 × 21.5 9.75× m9.75 m AverageAverage room room height height 7.2 m 7.2 m AverageAverage room roomvolume volume 1510 m15103 m3 Plan typologyPlan typology Transverse Transverse rectangular rectangular plan plan Capacity 263 Capacity 263 Volume per person 5.74 m3 Volume per person 5.74 m3

TheThe women’s women’s hall hall is locatedis located on on the the narthex, narthex, which which is coveredis covered with with glass glass surfaces surfaces and and is separatedis separated from from the the main main prayer prayer hall hall by by wooden wooden lattice lattice surfaces. surfaces. The The inner inner surface surface of theof the marblemarble mihrab mihrab was was covered covered with with tiles. tiles. There There is ais marble a marble mimbar mimbar in thein the west west and and a sermon a sermon chairchair made made using using marble marble in in the the easteast ofof the mihrab. There There is is a awooden wooden muezzin muezzin lodge lodge west westof the of the entrance entrance door. door. The The walls walls of the of themosque mosque are arecovered covered with with wooden wooden panels panels up to up 1.2 tom 1.2 from m from the thefloor. floor. The The floor floor of the of thebuilding building is covered is covered with with carpet, carpet, and and the the walls walls are are plas- plastered and painted (Figure5). The mosque is located near the city center, surrounded by tered and painted (Figure 5). The mosque is located near the city center, surrounded by residences, and pedestrian and traffic roads. residences, and pedestrian and traffic roads.

Figure 5. Main and women’s prayer hall of Attar Ece Mosque (photos by the authors).

3.5. E˘glenhocaMosque

The mosque, built in 1902 in Izmir,˙ has a longitudinal rectangular plan. The ceiling system consists of a central wooden dome and a wooden ﬂat ceiling. The inner surface of mihrab is covered by wooden materials. The mimbar of mosque is also wooden. The women’s hall is visually separated from the main prayer hall using perforated wooden panels. The women’s prayer hall is supported by wooden pillars and expanded towards the main worship area. There are wooden, plaster and stone decorations inside. There are wooden decorations on the wooden dome, which is an element of the upper cover structure of the mosque, and plaster decorations on the mihrab. The ﬂoor of the mosque and the women’s hall are covered with carpets (Figure6). The mosque is surrounded by coffee houses, shops, houses, and car parks. Acoustics 2021, 4 FOR PEER REVIEW 8

Figure 5. Main and women’s prayer hall of Attar Ece Mosque (photos by the authors).

3.5. Eğlenhoca Mosque The mosque, built in 1902 in İzmir, has a longitudinal rectangular plan. The ceiling system consists of a central wooden dome and a wooden flat ceiling. The inner surface of mihrab is covered by wooden materials. The mimbar of mosque is also wooden. The women’s hall is visually separated from the main prayer hall using perforated wooden panels. The women’s prayer hall is supported by wooden pillars and expanded towards the main worship area. There are wooden, plaster and stone decorations inside. There are wooden decorations on the wooden dome, which is an element of the upper cover structure of the mosque, and plaster decorations on the mihrab. The floor of the mosque and the women’s hall are covered with carpets (Figure 6). The mosque is surrounded by coffee houses, shops, houses, and car parks. Acoustics 2021, 3 566 Table 5. The architectural features of Eğlenhoca Mosque.

Eğlenhoca Mosque Table 5. TheLocation architectural features of E˘glenhocaMosque. İzmir Year of construction 1902 System of ceiling E˘glenhocaMosque Wooden dome and flat ceiling Plan dimensionsLocation 12.54 × 14.9Izmir˙ m AverageYear room of construction height 7.15 m 1902 System of ceiling Wooden dome and ﬂat ceiling 3 Average Planroom dimensions volume 1360 12.54 m × 14.9 m PlanAverage typology room height Rectangular (mihrab is located 7.15 m on the long side) AverageCapacity room volume 2011360 m3 Volume Planper person typology Rectangular (mihrab 6.77 m is3 located on the long side) Capacity 201 Volume per person 6.77 m3

FigureFigure 6. 6.Main Main andand women’swomen’s prayer prayer hall hall of of E˘glenhocaMosque Eğlenhoca Mosque (photos (photos by by the the authors). authors).

3.6.3.6. MahkemeMahkeme MosqueMosque ThisThis mosque,mosque, which was was built built in in 1700 1700 in in İzmirIzmir˙ has has a transverse a transverse rectangular rectangular plan. plan. The Themosque mosque is covered is covered by bya single a single wooden wooden dome dome centrally centrally and and side side aisles aisles are coveredcovered byby woodenwooden ﬂat flat ceilings. ceilings. The The perforated perforated wooden wooden panels panels of of the the women’s women’s prayer prayer hall, hall, located located in thein the northern northern part part ofthe of the mosque, mosque, separating separating the the hall hall from from the the main main worship worship area area visually. visu- Theally. mimbar The mimbar and the and pulpit the pulpit are made are ofmade marble. of marble. The mihrab The mihrab has a half has cylinder a half cylinder body and body is paintedand is painted over plaster. over plaster. The ﬂoor The of floor the mosque of the mosque is covered is covered by carpets by carpets (Figure 7(Figure). 7).

Table 6. The architectural features of Mahkeme Mosque.

Mahkeme Mosque Location Izmir˙ Year of construction 1700 System of ceiling Wooden dome and ﬂat ceiling Plan dimensions 20 × 11.9 m Average room height 5.85 m Average room volume 1559 m3 Plan typology Rectangular (Mihrab is located on the short side) Capacity 2497 Volume per person 5.25 m3 Acoustics 2021, 4 FOR PEER REVIEW 9

Table 6. The architectural features of Mahkeme Mosque.

Mahkeme Mosque Location İzmir Year of construction 1700 System of ceiling Wooden dome and flat ceiling Plan dimensions 20 × 11.9 m Average room height 5.85 m Average room volume 1559 m3 Plan typology Rectangular (Mihrab is located on the short side) Acoustics 2021, 3 Capacity 2497 567 Volume per person 5.25 m3

Figure 7. Main prayer hall of Mahkeme Mosque (photos by the authors). Figure 7. Main prayer hall of Mahkeme Mosque (photos by the authors). 3.7. Çar¸sıMosque 3.7. Çarşı Mosque The mosque was built in 1311 in Izmir.˙ Although walls were built on a masonry system, the topThe covering mosque system was built consists in 1311 of ain central İzmir. woodenAlthough dome walls with were a diameterbuilt on a of masonry 4.8 m and sys- a woodentem, the ﬂattop ceilingcovering (Figure system8). consists The mosque, of a ce withntral plan wooden dimensions dome with of 15.3 a diameter× 13.8 m, of has4.8 m a planand a close wooden to a squareflat ceiling shape. (Figure 8). The mosque, with plan dimensions of 15.3 × 13.8 m, has a plan close to a square shape. Table 7. The architectural features of Çar¸sıMosque. Table 7. The architectural features of Çarşı Mosque. Çar¸sıMosque Çarşı Mosque Location Izmir˙ LocationYear of constructionİzmir 14th century Year of constructionSystem of ceiling Wooden 14th century dome and ﬂat ceiling System ofPlan ceiling dimensions Wooden dome and 15.3 ×flat13.76 ceiling m Plan dimensionsAverage room height 15.3 × 13.76 7.75 m m Average room volume 3 Average room height 7.75 m1659 m Plan typology Transverse rectangular plan Average room volume 1659 m3 Acoustics 2021, 4 FOR PEER REVIEW Capacity 263 10 Plan typologyVolume per person Transverse rectangular6.31 m 3plan Capacity 263 Volume per person 6.31 m3

FigureFigure 8.8. MainMain andand women’swomen’s prayerprayer hallhall ofof Çar¸sıMosqueÇarşı Mosque (photos(photosby bythe theauthors). authors).

TheThe mainmain worshipworship area area and and lodge lodge for for women women have have carpets carpets as as a floor-finishing a floor-finishing material. mate- Therial. mimbar,The mimbar, sermon sermon chair, chair, women’s women’s prayer prayer hall, columns, hall, columns, and wall and coverings wall coverings up to 0.9 up cm to from0.9 cm the from floor the are floor made are of made wood. of The wood. mosque The mosque is positioned is positioned higher than higher the than level the of roadlevel andof road the and entrance the entrance of the mosque of the mosque is reached is reach by steps.ed by steps. It is located It is located at the at city the center city center and surroundedand surrounded by shops, by shops, a marketplace, a marketplace, dwellings, dwellings, traffic, traffic, and pedestrianand pedestrian walkways. walkways.

3.8.3.8. GöçbeyliGöçbeyli MerkezMerkez MosqueMosque ThisThis mosque,mosque, whichwhich waswas builtbuilt inin thethe 19th19th centurycentury inin Izmir,˙İzmir, hashas aa planplan withwith anan interiorinterior lengthlength ofof 13.913.9 mm andand aa widthwidth ofof 14.314.3 m.m. TheThe ceilingceiling structurestructure ofof thethe mosquemosque hashas aa singlesingle wooden dome centrally with a diameter of 4.7 m. Side aisles are covered by wooden vaults. Wall surfaces are covered by plaster and paint. The carpet is used as a floor finish material in the mosque (Figure 9). Wood is widely used in the ceiling structure, prayer area for women, columns, sermon chair, and mimbar. The mosque is located in a village and is surrounded by many one story dwellings.

Table 8. The architectural features of Göçbeyli Merkez Mosque.

Göçbeyli Merkez Mosque Location İzmir Year of construction 1895 System of ceiling Wooden dome and vault ceiling Plan dimensions 14.26 × 13.9 m Average room height 5.65 m Average room volume 1330 m3 Plan typology Square Capacity 247 Volume per person 5.38 m3

Figure 9. Main prayer hall and women’s prayer hall of Göçbeyli Mosque (photos by the authors).

Acoustics 2021, 4 FOR PEER REVIEW 10

Figure 8. Main and women’s prayer hall of Çarşı Mosque (photos by the authors).

The main worship area and lodge for women have carpets as a floor-finishing material. The mimbar, sermon chair, women’s prayer hall, columns, and wall coverings up to 0.9 cm from the floor are made of wood. The mosque is positioned higher than the level of road and the entrance of the mosque is reached by steps. It is located at the city center and surrounded by shops, a marketplace, dwellings, traffic, and pedestrian walkways.

Acoustics 2021, 3 3.8. Göçbeyli Merkez Mosque 568 This mosque, which was built in the 19th century in İzmir, has a plan with an interior length of 13.9 m and a width of 14.3 m. The ceiling structure of the mosque has a single wooden dome centrally with a diameter of 4.7 m. Side aisles are covered by wooden woodenvaults. Wall dome surfaces centrally are with covered a diameter by plaster of 4.7 and m. paint. Side aisles The carpet are covered is used by as wooden a floor vaults.finish Wallmaterial surfaces in the are mosque covered (Figure by plaster 9). Wood and paint. is widely The carpet used isin used the ceiling as a ﬂoor structure, ﬁnish material prayer areain the for mosque women, (Figure columns,9). Woodsermon is chair, widely and used mimbar. in the The ceiling mosque structure, is located prayer in areaa village for women, columns, sermon chair, and mimbar. The mosque is located in a village and is and is surrounded by many one story dwellings. surrounded by many one story dwellings. Table 8. The architectural features of Göçbeyli Merkez Mosque. Table 8. The architectural features of Göçbeyli Merkez Mosque. Göçbeyli Merkez Mosque Location Göçbeyli Merkez Mosque İzmir Year of constructionLocation 1895 Izmir˙ SystemYear of ceiling of construction Wooden dome and vault 1895 ceiling Plan dimensionsSystem of ceiling Wooden 14.26 × 13.9 dome m and vault ceiling Average roomPlan height dimensions 5.65 14.26m × 13.9 m Average roomAverage volume room height 1330 m3 5.65 m 3 PlanAverage typology room volume Square 1330 m Plan typology Square Capacity 247 Capacity 247 Volume per person 5.38 m3 Volume per person 5.38 m3

Figure 9. Main prayer hall and women’s prayer hall of Göçbeyli Mosque (photos by thethe authors).authors).

3.9. Preliminary Classification of Cases Depending on Ceiling Structure In the literature, there are some studies on the classification of mosques according to spatial, chronological, typological, functional features and urban locations. A few studies have received attention on the acoustical characteristics of mosques with a classification [19,30]. They show that the features of geometrical parameters such as plan typology, volume, etc. affect the acoustical conditions of mosques. Similarly, selected mosques are classified according to architectural features of the main prayer hall, in this section. Eight mosques with wooden and masonry ceilings, which were expected to show different acoustic behavior, are divided into two main groups. Masonry top-covered mosques are divided into two groups depending on whether they have a single-domed or curvilinear (multi-domed) composition. The mosques with wooden ceilings are divided into two separate classes: mosques with a curvilinear composition, such as a dome, and a vault or a flat ceiling in the top cover system, and mosques covered with a flat wooden ceiling (Table9). Under the headings of suggested classifications in the Table9, different ceiling structures and material properties of selected cases of the study are shown in Table 10. Acoustics 2021, 4 FOR PEER REVIEW 11

AcousticsAcousticsAcousticsAcoustics 20212021 2021 2021,, 4,4 ,4 FOR4FOR FOR FOR PEERPEER PEER PEER REVIEWREVIEW REVIEW REVIEW 11111111 Acoustics 2021, 4 FOR PEER REVIEW 11 Acoustics 2021, 4 FOR PEER REVIEW 11

3.9. Preliminary Classification of Cases depending on Ceiling Structure 3.9. Preliminary Classification of Cases depending on Ceiling Structure 3.9.3.9.3.9. PreliminaryPreliminary PreliminaryIn the literature, ClassificationClassification Classification there are ofof of CasesCases someCases dependindependin dependinstudies ggong onon on the CeilingCeiling Ceiling classification StructureStructure Structure of mosques according to spatial,3.9. PreliminaryIn chronological,the literature, Classification theretypological, are of Casessome functional dependinstudies on gfeatures on the Ceiling classification and Structure urban locations.of mosques A accordingfew studies to InInIn thethe the literature,literature, literature, therethere there areare are somesome some studiesstudies studies onon on thethe the classificationclassification classification ofof of mosquesmosques mosques accordingaccording according toto to havespatial, Inreceived the chronological, literature, attention there typological, on theare someacoustical functional studies characteristics on features the classification and of urbanmosques of locations. mosques with a Aclassification according few studies to spatial,spatial,spatial, chronological,chronological, chronological, typological,typological, typological, functionalfunctional functional featuresfeatures features andand and urbanurban urban locations.locations. locations. AA A fewfew few studiesstudies studies [19,30].spatial,have received Theychronological, show attention that typological, the on features the acoustical functional of geometrical characteristics features parameters and of urban mosques such locations. as withplan atypology, A classification few studies vol- havehavehave received receivedreceived attention attentionattention on onon the thethe acoustical acousticalacoustical characteristics characteristicscharacteristics of ofof mosques mosquesmosques with withwith a aa classification classificationclassification ume,have[19,30]. etc.received They affect show attentionthe acoustic that theonal thefeatures conditions acoustical of geometrical of characteristics mosques. parameters of mosques such as with plan a typology, classification vol- [19,30].[19,30].[19,30]. TheyThey They showshow show thatthat that thethe the featuresfeatures features ofof of geometricalgeometrical geometrical parametersparameters parameters suchsuch such asas as planplan plan typology,typology, typology, vol-vol- vol- [19,30].ume,Similarly, etc. They affect show selected the thatacoustic themosques featuresal conditions ar eof classified geometrical of mosques. according parameters to ar suchchitectural as plan features typology, of vol-the ume,ume,ume, etc.etc. etc. affectaffect affect thethe the acousticacoustic acousticalalal conditionsconditions conditions ofof of mosques.mosques. mosques. mainume, Similarly,prayeretc. affect hall, theselected in acousticthis section. mosquesal conditions Eight are mosquesclassified of mosques. with according wooden to and architectural masonry ceilings, features which of the Similarly,Similarly,Similarly, selected selectedselected mosques mosquesmosques ar arareee classified classifiedclassified according accordingaccording to toto ar ararchitecturalchitecturalchitectural features featuresfeatures of ofof the thethe weremain Similarly, expectedprayer hall, toselected inshow this mosquesdifferentsection. Eight aracoustice classified mosques behavior, withaccording woodenare divided to arandchitectural masonryinto two featuresceilings,main groups. whichof the mainmainmain prayerprayer prayer hall,hall, hall, inin in thisthis this section.section. section. EightEight Eight mosquesmosques mosques withwith with woodenwooden wooden andand and masonrymasonry masonry ceilings,ceilings, ceilings, whichwhich which Masonrymainwere prayerexpected top-covered hall, to in show this mosques section. different are Eight acoustic divided mosques behavior,into with two wooden groupsare divided dependingand masonry into two on ceilings, whethermain groups. which they werewerewere expected expectedexpected to toto show showshow different differentdifferent acoustic acousticacoustic behavior, behavior,behavior, are areare divided divideddivided into intointo two twotwo main mainmain groups. groups.groups. havewereMasonry aexpected single-domed top-covered to show mosquesor different curvilinear are acoustic divided (multi-domed) behavior, into two are groupscomposition. divided depending into The two onmosques mainwhether groups. with they MasonryMasonryMasonry top-covered top-coveredtop-covered mosques mosquesmosques are areare divided divideddivided into intointo two twotwo groups groupsgroups depending dependingdepending on onon whether whetherwhether they theythey woodenMasonryhave a ceilingssingle-domed top-covered are divided mosques or cu intorvilinear are two divided separa(multi-domed) intote classes: two groups mosquescomposition. depending with Thea curvilinearon mosques whether com- theywith havehavehave aaa single-domedsingle-domedsingle-domed ororor cucucurvilinearrvilinearrvilinear (multi-domed)(multi-domed)(multi-domed) composition.composition.composition. TheTheThe mosquesmosquesmosques withwithwith position,havewooden a single-domedsuchceilings as a are dome, divided or and cu rvilinearainto vault two or separa(multi-domed)a flat ceilingte classes: in thecomposition. mosques top cover with system, The a curvilinear mosques and mosques com-with woodenwoodenwooden ceilings ceilingsceilings are areare divided divideddivided into intointo two twotwo separa separaseparatetete classes: classes:classes: mosques mosquesmosques with withwith a aa curvilinear curvilinearcurvilinear com- com-com- coveredwoodenposition, withceilings such a asflat area dome,wooden divided and ceiling into a vault two (Table or separa a flat 9). Underceilingte classes: thein the mosquesheadings top cover withof system,suggested a curvilinear and classifica- mosques composition,position,position, suchsuch such asas as aa a dome,dome, dome, andand and aa a vaultvault vault oror or aa a flatflat flat ceilingceiling ceiling inin in thethe the toptop top covercover cover system,system, system, andand and mosquesmosques mosques tionsposition,covered in the withsuch Table aas flat a 9, dome, woodendifferent and ceiling aceiling vault (Table orstructur a flat 9). ceilinges Under and inmaterial the the headings top properties cover of system, suggested of selected and classifica- mosques cases coveredcoveredcovered with withwith aa a flatflat flat wooden woodenwooden ceiling ceilingceiling (Table(Table (Table 9).9). 9). Under UnderUnder the thethe headings headingsheadings of ofof suggested suggestedsuggested classifica- classifica-classifica- ofcoveredtions the studyin thewith areTable a flatshown 9, wooden different in Table ceiling ceiling 10. (Table structur 9). Underes and thematerial headings properties of suggested of selected classifica- cases tionstionstions in inin the thethe Table TableTable 9, 9,9, different differentdifferent ceiling ceilingceiling structur structurstructureseses and andand material materialmaterial properties propertiesproperties of ofof selected selectedselected cases casescases Acoustics 2021, 3 tionsof the in study the Table are shown 9, different in Table ceiling 10. structures and material properties of selected cases569 ofofof thethe the studystudy study areare are shownshown shown inin in TableTable Table 10.10. 10. Table 9. The classification ofof mosques the study in the are study shown according in Table to 10.features of the roof/ceiling systems facing the interior TableTable 9. 9. The The classification classification of of mosques mosques in in the the study study according according to to features features of of the the roof/ceiling roof/ceiling systems systems facing facing the the interior interior TableTableTable 9.9. 9. TheThe MasonryThe classificationclassification classification Roof Construction ofof of mosquesmosques mosques inin in thethe the studystudy study accordingaccording according toto to featuresfeatures features Wooden ofof of thethe the roof/ceilingRoofroof/ceiling roof/ceiling + Ceiling systemssystems systems Construction facingfacing facing thethe the interiorinterior interior Table 9. The classification of mosques in the study according to features of the roof/ceiling systems facing the interior Single-DomedTable 9.Masonry MasonryThe classiﬁcation Roof Roof CurvilinearConstruction Construction of mosques Composition in the studyFlat according Ceiling to features Wooden Wooden of Curvilinear the Roof Roof roof/ceiling + + Ceiling Ceiling Composition Construction systemsConstruction facing the interior. MasonryMasonryMasonry RoofRoof Roof ConstructionConstruction Construction Wooden Wooden Wooden RoofRoof Roof ++ + CeilingCeiling Ceiling ConstructionConstruction Construction Single-DomedSingle-DomedMasonry Roof (Multi-Domed)CurvilinearConstructionCurvilinear Composition Composition FlatFlat Ceiling Ceiling Wooden Curvilinear Curvilinear Roof + Ceiling Composition Composition Construction Single-DomedSingle-DomedSingle-DomedMasonry RoofCurvilinear ConstructionCurvilinearCurvilinear CompositionComposition Composition FlatFlatFlat CeilingCeiling Ceiling Wooden Curvilinear CurvilinearDome Curvilinear Roof + +Flat Ceiling CompositionComposition CompositionCeiling Construction Dome + Vault (Multi-Domed)(Multi-Domed) Single-DomedSingle-Domed (Multi-Domed)(Multi-Domed)Curvilinear(Multi-Domed)Curvilinear CompositionComposition FlatFlat Ceiling Ceiling Curvilinear Curvilinear Composition Composition (Multi-Domed) DomeDome + + Flat Flat Ceiling Ceiling Dome Dome + + Vault Vault Lalapaşa Mosque (Multi-Domed)İ(Multi-Domed)vazpaşa Mosque Attarece Mosque DomeDome EDomeğlenhoca ++ + FlatFlat Flat Mosque CeilingCeiling Ceiling Dome Dome GöçbeyliDome ++ + VaultVault Vault Mosque DomeDome + + FlatFlat CeilingCeiling Dome Dome ++ VaultVault LalapaLalapaşşaa Mosque Mosque İİvazpavazpaşşaa Mosque Mosque Attarece Attarece Mosque Mosque E Eğğlenhocalenhoca Mosque Mosque Göçbeyli Göçbeyli Mosque Mosque LalapaLalapaLalapa¸saMosqueLalapaşşaşaa MosqueMosque Mosque İİvazpaIvazpa¸saMosque˙İvazpavazpaşşaşaa MosqueMosque Mosque Attarece Attarece Attarece Mosque Mosque Mosque E EE˘glenhocaMosque Eğğğlenhocalenhocalenhoca MosqueMosque Mosque Göçbeyli GöçbeyliGöçbeyli Göçbeyli MosqueMosque MosqueMosque Lalapaşa Mosque İvazpaşa Mosque Attarece Mosque Eğlenhoca Mosque Göçbeyli Mosque

for central dome;

plan dimensions: 9.75 × Ø=forfor 7.85central central m H=dome; dome; 3.5 m Ødome= 4.3 m forforfor centralcentral central dome;dome; dome; plan21.5plan dimensions:m dimensions: 9.75 × Ødome=9.77 m for side domes; planplanplan dimensions:dimensions: dimensions: 9.759.75 9.75 ×× × dome forØ=Ø= central7.85 7.85 m m dome;H=H= 3.5 3.5 m m plan dimensions: 9.75 × ØHØdomedome== 1.9 4.3 m m Ø=Ø=Ø=for 7.857.85 7.85central mm m H=H= H=dome; 3.53.5 3.5 mm m 9.75the21.5 height× m21.5 of m mosque: ØØØdomedomedome=== 4.34.3 4.3 mm m Hdome= 3 m Ø= 7.85 m H= 3.5 m 21.5plan m dimensions: 9.75 × Ødome= 4.33 m ØØdomedome=9.77=9.77 m m Ø=forfor 3.23side 7.85side mdomes; domes; H= H = 13.5 m m 21.521.521.5 mm m HV=1360Hdomedome= m1.9 m ØØØdomedomedome=9.77=9.77=9.77 mm m forforforØ= sideside side7.85 domes;domes; domes;m H= 3.5 m the7.2 heightm of mosque: HHHØdomedomedomedome=== = 1.91.9 1.94.3 mm mm Ø dome=9.77= 9.773 m m for side domes; thethe height height of of mosque: mosque: dome 3 dom V=Hdomedome 1060= 3m m Ø=for side2.53 m domes; H= 1 m thethethe21.5 heightheight height m ofof of mosque:mosque: mosque: VH = 1360= 1.9 m m3 Ø e= 4.7 m Hdomedomedomedome= 3 m Ø=Ø= 3.23 3.23 m m H= H= 1 1 m m 7.2the m height 3of mosque: V=1360 m333 HHHHØdome== ==9.77 33= 3 mm 3m m m Ø=Ø=Ø=for 3.233.23 3.23side mm mdomes; H=H= H= 11 1 mm m V= 1510 m V=1360V=1360V=1360Hdome= m m 1.9m 3 m Hdome= 3 m 3 Ø= 3.23 m 3H= H = 1 1m m 7.27.2 m m 3 V=1360 m Hdome= 1.7 m V= 1060 m3333 V=Ø= 1406 2.53 mm H= 1 m 7.2V7.27.2the = mm 1510 mheight m of mosque: ØØØdomdome=e== 4.7 4.7 m m V=V=V=H dome10601060 1060= m3m m m 3 Ø= 2.533.23 m H= 1 m 7.2 m 3 ØØØdomdomdomedome=e=e= 4.74.7 4.7 mm m VV= = 1060 1060 m m Ø=Ø=Ø= 2.532.53 2.53 mm m H=H= H= 11 1 mm m V= 1510 m33 V=1360 m Ødome= 4.73 m Ø= 2.53 m H= H3 = 1 1m m V= 1510 m33 3 V=dome 1330 m 3 ÇeV=ş nigir1406 mMosque333 V=V=V=7.2 15101510 1510m mm m 3 Menemen Mosque HHHdomedome== 1.7 1.7 1.7 m m m V= 1060 m V=V=V=Ø= 14061406 14062.53 mm m 3H=3 1 m V= 1510 m HHHØdomedomedomedom==e= = 1.71.7 1.7 4.7 mm m m VV= = 1406 1406 m m 3 Hdome= 1.7 m3 V= 1510 m VV= = 13301330 mm33 ÇeÇeşşnigirnigir Mosque Mosque3 Menemen Menemen Mosque Mosque V=V=H dome1330 1330= m1.7 m33 3m ÇeÇeÇe¸snigirMosqueÇeV=şşnigirşnigir 1406nigir MosqueMosquem Mosque Menemen Menemen Menemen MosqueMosque Mosque V=V= 1330 1330 m m 3 Çeşnigir Mosque Menemen Mosque V= 1330 m3

Ødome= 8.7 m

for central dome; ØHØdomedomedome== 4.3 8.7 m m ØØØdomedomedome=== 8.78.7 8.7 mm m HØdome== 8.7 4.3 m m Ø=8.87forfor central central m dome; dome; V=1559Hdomedome= m³4.3 m forforfor centralcentral central dome;dome; dome; HHHØdomedomedomedome=== = 4.34.3 4.38.7 mm 3mm Øfor = central 8.87 m dome; VH =dome 1559= 4.3 m m H=3.45Ø=8.87Ø=8.87 m m ÇarV=1559V=1559şı Mosque m³ m³ Ø=8.87Ø=8.87HØ=8.87for = central 3.45 mm m m dome; V=1559V=1559Çar¸sıMosqueV=1559Hdome= m³ m³ 4.3m³ m forH=3.45H=3.45 side m domes;m ÇarÇarşşıı Mosque Mosque H=3.45H=3.45forH=3.45Ø=8.87 side mm mm domes; ÇarÇarÇarV=1559şşışı ıMosqueMosque MosqueMosque m³ Ø=forfor 3.31side side mdomes; domes; forforØforH=3.45 =sideside side 3.31 domes;domes; mdomes; m Çarşı Mosque H=HØ=Ø= = 1.553.31 1.553.31 m m Ø=Ø=Ø=for 3.313.31 3.31side mm mdomes; VV=H=H= = 17001.55 17001.55 m m³m 3 H=H=H=Ø= 1.551.55 1.553.31 mm mm V=V=V=H=V= 17001700 17001.551700 m³m³ mm³ m³ V= 1700 m³ V= 1700 m³ Ø = 4.8 m Ødomedome= 4.8 m AcousticsAcousticsAcousticsAcousticsAcoustics 2021 20212021 2021 2021, 4,,, 44FOR, FOR4FORFOR, 4FOR FOR PEER PEERPEERPEER PEER PEER REVIEW REVIEWREVIEWREVIEW REVIEW REVIEW 121212 12 12 Acoustics 2021, 4 FOR PEER REVIEW Hdome = 2.8 m 12 HØdomedome== 2.8 4.8 3m m ØVØdomedome =dome 1659== 4.8 4.8 m m m ØØdome== 4.8 4.8 m m V=1659Hdome= m³2.8 m HHØdomedomedomedome== =2.8 2.84.8 m mm HHdome== 2.8 2.8 m m V=1659V=1659 m³ m³ V=1659V=1659V=1659Hdome= m³ m³ 2.8m³ m TableTableTableTableTable 10. 10.10. 10.10. The10. TheThe The The Thephotos photosphotos photos photosphotos from fromfrom from fromfrom the thethe thethe theceilingthe ceilingceiling ceilingceiling ceilingceiling structures structuresstructures structuresstructures structuresstructures of ofof ofeighof of eighofeigh eighteigh eigh eight tthistoricalt historicalhistoricalthistoricalt historicalt historicalhistorical historical mosques mosquesmosquesV=1659mosques mosques mosquesmosques mosques m³ (photos (photos(photos (photos (photos (photos(photos (photos by bybyby by bybythe bythethethe the thethe authors)the authors)authors)authors) authors). authors)authors) authors)......

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EEEğğElenhocağE˘glenhocaM.Elenhocalenhocağlenhocağlenhocalenhoca M. M.M.M. M. M. Mahkeme Mahkeme Mahkeme Mahkeme Mahkeme Mahkeme Mahkeme Mosque MosqueMosque Mosque Mosque MosqueMosque Çar Çar¸sıMosque Çar Çar Çar Çar Çar Çarşışş ııMosqueış ş MosqueıMosqueşMosqueı ı MosqueMosque Mosque Göçbeyli Göçbeyli Göçbeyli Göçbeyli Göçbeyli Göçbeyli Göçbeyli Göçbeyli Mosque MosqueMosque Mosque Mosque

4.4.4. Acoustical4. Acoustical4.Acoustical4. Acoustical AcousticalAcoustical Measurements MeasurementsMeasurements Measurements MeasurementsMeasurements and andand andand and Results ResultsResults ResultsResults Results EightEightEightEightEightEight historical historicalhistorical historical historicalhistorical mosques mosquesmosques mosques mosquesmosques built builtbuilt built builtbuilt in inin inthe in inthethe the thetheAegean AegeanAegean AegeanAegean Aegean Region RegionRegion RegionRegion Region of ofof ofTurkeyof ofTurkeyTurkey Turkey Turkey were werewere were were determined determineddetermined determined determined as asas as as researchresearchresearchresearchresearchresearch subjects subjectssubjects subjects subjectssubjects to toto to be to tobebe be comparedbe be comparedcompared compared comparedcompared and andand and andand classified classifiedclassified classifiedclassified classified according accordingaccording accordingaccording according to toto totheirto totheirtheir theirtheir their acoustical acousticalacoustical acoustical acoustical characteris- characteris-characteris- characteris- characteristics.tics.tics.tics.tics.tics.tics. The TheTheThe The TheThe geometrical geometricalgeometricalgeometrical geometrical geometricalgeometrical parameters parametersparametersparameters parameters parametersparameters such suchsuchsuch such suchsuch as asasas asvolume,as asvolume,volume,volume, volume,volume, volume, area, area,area,area, area,area, area, the thethethe thethe theheight heightheightheight heightheight height of ofofof ofofvolume, ofvolume,volume,volume, volume,volume, volume, and andandand and and the thethethe the thedi- di-di-di- di- di- ametersametersametersametersametersameters of ofof ofdomes of domesofdomes domes domesdomes are areare are arearemeasured measuredmeasured measured measuredmeasured during duringduring duringduring during the thethe thethe thefieldwork. fieldwork.fieldwork. fieldwork.fieldwork. fieldwork. SelectedSelectedSelectedSelectedSelectedSelected mosques mosquesmosques mosques mosquesmosques were werewere were werewere evaluated evaluatedevaluated evaluated evaluatedevaluated by byby byby using by usingusing usingusing using objective objectiveobjective objectiveobjective objective acoustic acousticacoustic acousticacoustic acoustic parameters parametersparameters parameters parameters and andand and and meas- meas-meas- meas- meas- urementsurementsurementsurementsurementsurements were werewere were werewere carried carriedcarried carried carriedcarried out outout out out outfollowing followingfollowing following followingfollowing by byby byby ISO by ISOISO ISOISO ISO 3382-1 3382-13382-1 3382-13382-1 3382-1 standard, standard,standard, standard,standard, standard, as asas asin asinin inthe theinthe the theliterature literatureliterature literature literature [33]. [33].[33]. [33]. [33]. Ac- Ac-Ac- Ac- Ac- cordingcordingcordingcordingcordingcording to toto toAletta to AlettatoAletta Aletta AlettaAletta and andand and andand Kang; Kang;Kang; Kang; Kang;Kang; “For “For“For “For “For “For the thethe thethe themeasurem measuremmeasurem measuremmeasurem measurements,ents,ents,ents,ents,ents, the thethe thethe theresearchers’ researchers’researchers’ researchers’researchers’ researchers’ work workwork work work should shouldshould should should always alwaysalways always always bebebe becommended,be be commended,commended, commended, commended,commended, for forfor for forthefor thethe the thetheconsiderable considerableconsiderable considerable considerableconsiderable challenges challengeschallenges challenges challengeschallenges they theythey theythey they face faceface faceface face in inin inimplementingin inimplementingimplementing implementing implementing standardized standardizedstandardized standardized standardized measurementmeasurementmeasurementmeasurementmeasurementmeasurement protocols protocolsprotocols protocols protocolsprotocols in inin locationsin in locationsinlocations locations locations locations that thatthat that that that often oftenoften oftenoften often present presentpresent presentpresent present serious seriousserious seriousserious serious accessibility accessibilityaccessibility accessibility accessibility and andand and and operability operabilityoperability operability operability issues”issues”issues”issues”issues”issues”issues” [2]. [2].[2].[2]. [2]. [2].[2].Since SinceSinceSince Since SinceSince there theretherethere there therethere are areareare are are areno nonono no noparticular no particularparticularparticular particular particularparticular standards standardsstandardsstandards standardsstandards standards or ororor orordefinitions ordefinitionsdefinitionsdefinitions definitionsdefinitions definitions for forforfor forfor mosques,for mosques,mosques,mosques, mosques,mosques, mosques, T30, T30,T30,T30, T30, T30, bass bassbassbass bass bass ratio,ratio,ratio,ratio,ratio,ratio, EDT, EDT,EDT, EDT, EDT,EDT, C80, C80,C80, C80, C80,C80, D50, D50,D50, D50, D50,D50, STI, STI,STI, STI, STI,STI, and andand and andand background backgroundbackground background backgroundbackground noise noisenoise noisenoise noise level levellevel levellevel level were werewere werewere were chosen chosenchosen chosenchosen chosen to toto tobe tobebe beused be usedused used used to toto toinvesti- investi-toinvesti- investi- investi- gategategategategategate the thethe the thetheacoustic acousticacoustic acoustic acousticacoustic conditions conditionsconditions conditions conditionsconditions of ofof of volumesof ofvolumesvolumes volumes volumesvolumes due duedue due duedue to toto to theto tothethe the the thepresence presencepresence presence presencepresence of ofof of both ofbothboth both both music musicmusic music music and andand and and speech speechspeech speech speech ritualsritualsritualsritualsritualsrituals in inin inmosques. in mosques.inmosques. mosques. mosques.mosques.

4.1.4.1.4.1.4.1.4.1. 4.1.Measurement MeasurementMeasurement Measurement MeasurementMeasurement Conditions ConditionsConditions Conditions ConditionsConditions AcousticalAcousticalAcousticalAcousticalAcousticalAcoustical field fieldfield field fieldfield measurements measurementsmeasurements measurements measurementsmeasurements were werewere were werewere held heldheld held heldheld during duringduring during duringduring the thethe thethe thedaytime daytimedaytime daytimedaytime daytime in inin in unoccupied inunoccupiedunoccupied unoccupied unoccupied halls hallshalls halls halls followingfollowingfollowingfollowingfollowingfollowingfollowing ISO ISOISOISO ISO ISOISO 3382-1:2010 3382-1:20103382-1:20103382-1:2010 3382-1:2010 3382-1:20103382-1:2010 [33]. [33].[33].[33]. [33]. [33]. [33]. During DuringDuringDuring During During During the thethethe thethe theme mememe memeasurements, measurements,asurements,asurements,asurements,asurements, the thethe thethe thewindows windowswindows windows windows were werewere were were kept keptkept kept kept closed. closed.closed. closed. closed. TheTheTheTheTheThe omni omniomni omni omniomni power powerpower power powerpower sound soundsound sound soundsound source sourcesource source sourcesource (B&K (B&K(B&K (B&K (B&K(B&K Type TypeType Type TypeType 4292-L), 4292-L),4292-L), 4292-L),4292-L), 4292-L), connected connectedconnected connectedconnected connected to toto topower topowerpower power power amplifier amplifieramplifier amplifier amplifier (B&K (B&K(B&K (B&K (B&K TypeTypeTypeTypeTypeType 2734-A), 2734-A),2734-A), 2734-A), 2734-A),2734-A), was waswas was waswas located locatedlocated located locatedlocated in inin infront in infrontfront front frontfront of ofof ofthe of ofthethe the thethemihrab mihrabmihrab mihrabmihrab mihrab and andand andand and 1.50 1.501.50 1.501.50 1.50 m mm mfromm mfromfrom from from the thethe the thefloor floorfloor floor floor to toto torepresent torepresentrepresent represent represent thethethethethe thetheposition positionpositionposition position positionposition of ofofof ofthe of ofthethethe the thetheImam ImamImamImam Imam ImamImam while whilewhilewhile while whilewhile he hehehe he heis he isisis talkingis is talkingtalkingistalking talking talkingtalking and andand andand and giving givinggiving givinggiving giving orders ordersorders ordersorders orders to toto toprayers. toprayers.prayers. prayers. prayers. The TheThe The The receiver receiverreceiver receiver receiver pointspointspointspointspointspoints were werewere were werewere placed placedplaced placed placedplaced in inin in the in theinthe the thethemain mainmain main mainmain worship worshipworship worshipworship worship area areaarea areaarea area and andand andand and women’s women’swomen’s women’swomen’s women’s worship worshipworship worshipworship worship area areaarea area area at atat 0.85at 0.85at0.85 0.85 0.85 m mm mrepre- repre-mrepre- repre- repre- sentingsentingsentingsentingsentingsenting the thethe the thetheheight heightheight height heightheight of ofof ofthe of ofthethe the the theear earear ear ear earof ofof ofa of ofa a person a personapersona person personperson praying prayingpraying praying prayingpraying in inin inain ina a sitting aa sittingsittinga sittingsitting sitting position positionposition positionposition position on onon on the on thethe the thefloor. floor.floor. floor. floor. The TheThe The The receiverreceiverreceiverreceiverreceiverreceiver points pointspoints points pointspoints are areare are areareplaced placedplaced placed placedplaced in inin in such in insuchsuch such suchsuch a a a way a awaywaya way wayway th thth atth thatatth attheyat attheythey they theythey dominate dominatedominate dominate dominatedominate the thethe the thewhole wholewhole whole whole prayer prayerprayer prayer prayer area areaarea area area in inin in in mosquesmosquesmosquesmosquesmosquesmosques (Figure (Figure(Figure (Figure (Figure(Figure 10). 10).10). 10). 10). 10).DIRAC DIRACDIRAC DIRAC DIRACDIRAC Room RoomRoom RoomRoom Room Acoustics AcousticsAcoustics AcousticsAcoustics Acoustics Software SoftwareSoftware SoftwareSoftware Software Type TypeType TypeType Type 7841 78417841 7841 7841 v.6 v.6v.6 v.6 wasv.6 waswas was was used usedused used used to toto togener- gener-togener- gener- gener- ateateateate ateMLSate MLSMLS MLS MLSMLS signals signalssignals signals signalssignals with withwith with withwith a a alonger a longerlongera a longer longer longer period periodperiod period period period than thanthan thanthan than th thth e ththe ethestimated eestimatedestimatede e estimatedestimated estimated reverberation reverberationreverberation reverberationreverberation reverberation time timetime time time of ofof ofthe theofthe the thevolume. volume.volume. volume. volume. DiracDiracDiracDiracDiracDirac is isis alsois isalsoisalso also alsoalso used usedused used usedused to toto topostprocessing to topostprocessingpostprocessing postprocessing postprocessingpostprocessing impulse impulseimpulse impulse impulseimpulse responses responsesresponses responsesresponses responses for forfor forfor foreach eacheach eacheach each receiver receiverreceiver receiver receiver point. point.point. point. point. Impulse ImpulseImpulse Impulse Impulse responsesresponsesresponsesresponsesresponsesresponses were werewere were werewere recorded recordedrecorded recorded recordedrecorded using usingusing using using using the thethe the the theomnidirect omnidirectomnidirect omnidirect omnidirect omnidirectionalionalionalionalionalionalional microphone microphonemicrophonemicrophone microphonemicrophone microphone (B&K (B&K(B&K(B&K (B&K(B&K (B&K Type TypeTypeType TypeType Type 4189ZC-0032) 4189ZC-0032)4189ZC-0032)4189ZC-0032) 4189ZC-0032) 4189ZC-0032) thatthatthatthatthatthatthat integrated integratedintegratedintegrated integrated integratedintegrated with withwithwith with withwith the thethethe the thethehandheld handheldhandheldhandheld handheld handheld handheld analyzer analyzeranalyzeranalyzer analyzeranalyzer analyzer (B&K-Type (B&K-Type(B&K-Type(B&K-Type (B&K-Type(B&K-Type (B&K-Type 2250-A) 2250-A)2250-A)2250-A) 2250-A)2250-A) 2250-A) for forforfor forfor allfor allallall allallthe all thethethe the thereceiver receiverreceiverreceiver receiver receiver points. points.points.points. points. points. Background noise levels were measured inside and outside of eight mosques by using a BackgroundBackgroundBackgroundBackgroundBackground noise noisenoise noise noise levels levelslevels levels levels were werewere were were measured measuredmeasured measured measured inside insideinside inside inside and andand and and outside outsideoutside outside outside of ofof ofeight ofeighteight eight eight mosques mosquesmosques mosques mosques by byby by using by usingusing using using a a a a a

Acoustics 2021, 3 570

4. Acoustical Measurements and Results Eight historical mosques built in the Aegean Region of Turkey were determined as research subjects to be compared and classified according to their acoustical characteristics. The geometrical parameters such as volume, area, the height of volume, and the diameters of domes are measured during the fieldwork. Selected mosques were evaluated by using objective acoustic parameters and measurements were carried out following by ISO 3382-1 standard, as in the literature [33]. According to Aletta and Kang; “For the measurements, the researchers’ work should always be commended, for the considerable challenges they face in implementing standardized measurement protocols in locations that often present serious accessibility and operability issues” [2]. Since there are no particular standards or definitions for mosques, T30, bass ratio, EDT, C80, D50, STI, and background noise level were chosen to be used to investigate the acoustic conditions of volumes due to the presence of both music and speech rituals in mosques.

4.1. Measurement Conditions Acoustical field measurements were held during the daytime in unoccupied halls following ISO 3382-1:2010 [33]. During the measurements, the windows were kept closed. The omni power sound source (B&K Type 4292-L), connected to power amplifier (B&K Type 2734-A), was located in front of the mihrab and 1.50 m from the floor to represent the position of the Imam while he is talking and giving orders to prayers. The receiver points were placed in the main worship area and women’s worship area at 0.85 m representing the height of the ear of a person praying in a sitting position on the floor. The receiver points are placed in such a way that they dominate the whole prayer area in mosques (Figure 10). DIRAC Room Acoustics Software Type 7841 v.6 was used to generate MLS signals with a longer period than the estimated reverberation time of the volume. Dirac is also used to postprocessing impulse responses for each receiver point. Impulse responses were recorded using the omnidirectional microphone (B&K Type 4189ZC-0032) that integrated with the handheld analyzer (B&K-Type 2250-A) for all the receiver points. Background noise levels were measured inside and outside of eight mosques by using a sound level meter. The aim carrying out of inside and outside measurements is to understand the acoustical conditions around the mosques. The background noise levels were recorded for 15 min for each mosque. T30 and EDT parameters are evaluated in the range of 125–4000 Hz for mosques. However, results for parameters D50 and C80 will be interpreted for frequencies of 500, 1000 and 2000 Hz, because frequencies below 500 Hz are insignificant for speech intelligibility and can be neglected [34]. Although the energies of the consonants that are active at high frequencies are low, these letters are important for the speech intelligibility. Vowels are active in the low-frequency range. High-frequency sounds (800–2300 Hz) are the main determinants of speech intelligibility. Frequencies of 4000 Hz and above affect intelligibility approximately 5% [35]. The masking of high-frequency due to low-frequency sounds reduce understandability of speech. This is a problem that can often be encountered in large volumes, where the reflections occur from large/ concave surfaces. Acoustics 2021, 4 FOR PEER REVIEW 13

sound level meter. The aim carrying out of inside and outside measurements is to understand the acoustical conditions around the mosques. The background noise levels were recorded for 15 min for each mosque. T30 and EDT parameters are evaluated in the range of 125–4000 Hz for mosques. However, results for parameters D50 and C80 will be interpreted for frequencies of 500, 1000 and 2000 Hz, because frequencies below 500 Hz are insignificant for speech intelligibility and can be neglected [34]. Although the energies of the consonants that are active at high frequencies are low, these letters are important for the speech intelligibility. Vowels are active in the low-frequency range. High-frequency sounds (800–2300 Hz) are the main determinants of speech intelligibility. Frequencies of 4000 Hz and above affect intelligibil- Acoustics 2021, 3 ity approximately 5% [35]. The masking of high-frequency due to low-frequency sounds571 reduce understandability of speech. This is a problem that can often be encountered in large volumes, where the reflections occur from large/ concave surfaces.

Figure 10. Sound sources and receiver points determined in the field measurements of selected Figure 10. Sound sources and receiver points determined in the field measurements of mosques. selected mosques. 4.2.4.2. Results Results of of Acoustic Acoustic Measurements Measurements 4.2.1.4.2.1. T30 T30 TheThe average average T30 T30 values values obtained obtained from from receiver receiver points points for for the the eight eight mosques mosques and and their their distributiondistribution in in the the frequency frequency range range of of 125–4000 125–4000 Hz Hz are are shown shown in in the the graph graph in in Figure Figure 11 11.. AccordingAccording to to the the graph, graph, mosques mosques with with masonry masonry ceiling ceiling structures structures have have higher higher T30 T30 values values thanthan mosques mosques with with wooden wooden ceiling ceiling structures structures at at almost almost all all frequencies. frequencies. T30 T30 values values are are higherhigher at at low low frequencies frequencies in in masonry masonry structures, structures, while while change change by by the the frequency frequency is is not not distinctivedistinctive within within the the wooden wooden covered covered mosques. mosques. In In other other words, words, T30 T30 values values can can create create a a flatterflatter line line depending depending on on frequency. frequency. This This can can be be explained explained by by the the absorbing absorbing characteristics characteristics ofof the the wooden wooden construction, construction, since since it it works works as as a a panel panel resonator. resonator. On On the the other other hand, hand, higher higher T30 values in low frequencies help to create a more appropriate environment for musical rituals in masonry top-covered mosques. It is observed that the number of domes does not affect the average T30 values at medium frequencies in mosques with masonry tops. Additionally, it can be said that the presence of a wooden dome or vault in wooden-covered mosques reduces the average T30 values for all frequencies compared to a flat wooden ceiling mosque. It can be seen from Figure 12 that averages of reverberation time in mosques with masonry top cover are higher at low frequencies than at medium and high frequencies. The average values at low, medium, and high frequencies show a more balanced distribution in mosques with wooden ceilings. It has been determined that the types of material used in the ceiling structure in mosques have an effect on the change in acoustic parameter value on all frequencies. In other words, the most effective criterion is material of the ceiling construction, so it can be said that the classification of the selected mosques into two groups according to the material type is appropriate. The wooden top-covered mosques have a Acoustics 2021, 4 FOR PEER REVIEW 14

T30 values in low frequencies help to create a more appropriate environment for musical rituals in masonry top-covered mosques. It is observed that the number of domes does not affect the average T30 values at medium frequencies in mosques with masonry tops. Additionally, it can be said that the presence of a wooden dome or vault in wooden-covered mosques reduces the average T30 values for all frequencies compared to a flat wooden ceiling mosque. It can be seen from Figure 12 that averages of reverberation time in mosques with masonry top cover are higher at low frequencies than at medium and high frequencies. The average values at low, medium, and high frequencies show a more balanced distribution in mosques with wooden ceilings. It has been determined that the types of material used in the ceiling structure in mosques have an effect on the change in acoustic parameter Acoustics 2021, 3 value on all frequencies. In other words, the most effective criterion is material of the ceil-572 ing construction, so it can be said that the classification of the selected mosques into two groups according to the material type is appropriate. The wooden top-covered mosques have a similar reverberation time range with the literature data in Figure 1, while masonry similar reverberation time range with the literature data in Figure1, while masonry ones ones have T30 values of around 2 s. have T30 values of around 2 s.

T30 3.00

2.50

2.00 ) S 1.50 T30 ( 1.00

0.50

0.00 125 250 500 1000 2000 4000 FREQUENCY (HZ)

Lalapaşa M. (MD) İvazpaşa M. (MMD) Çeşnigir M. (MMD) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF) Figure 11. The average values of T30 measured in the eight mosques. (MD; masonry single-domed,single- MMD;domed, masonry MMD; masonry multi-domed, multi-domed, WFC; wooden WFC; wooden ﬂat ceiling, flat ceiling, WDV; WDV; wooden wooden dome dome and vault, and vault, WDF; Acoustics 2021, 4 FOR PEER REVIEW 15 woodenWDF; wooden dome anddome ﬂat and ceiling). flat ceiling).

125–250 Hz 500–1000 Hz 2000–4000 Hz

MASONRY COVERED WOODEN COVERED 3.00

2.50

2.00 ) S 1.50 T30 ( 1.00

0.50

0.00 Lalapaşa M. İvazpaşa M. Çeşnigir M. Attar Hoca Göçbeyli M. Eğlenhoca Mahkeme Çarşı M. (MD) (MMD) (MMD) M. (WFC) (WDV) M. (WDF) M. (WDF) (WDF)

FigureFigure 12. 12.The The average average T30 T30 values values of of mosques mosques at at low, low, mid, mid, and and high high frequencies. frequencies.

4.2.2.4.2.2. Bass Bass Ratio Ratio TheThe bass bass ratio ratio is is relatedrelated toto thethe warmth of indoor indoor spaces. spaces. If If the the ratio ratio is ishigher higher than than 1.2, 1.2,the the warmth warmth of the ofthe mosque mosque can can be evaluated be evaluated as excellent as excellent [36]. [ 36It ].is Itregarded is regarded as poor as poorwhen whenthe ratio the ratiolower lower than than0.9. Table 0.9. Table 11 shows 11 shows that thatmasonry-covered masonry-covered mosques mosques have have higher higher bass bassratios ratios than than wooden wooden ceiling ceiling types. types. This Thisparameter parameter can be can used be usedto evaluate to evaluate “sacred “sacred sensa- sensation”tion” of the of main the main prayer prayer hall, hall, since since the thelow low frequencies frequencies are areimportant important for forthat that feeling. feeling. Ac- Accordingcording to to results, results, the the feeling feeling of ofsacred sacred sensation sensation in the inthe prayer prayer halls halls of Lalapa of Lalapa¸saandşa and İvaz- ˙ Ivazpa¸saMosquespaşa Mosques can can be beevaluated evaluated as better as better than than other other mosques. mosques.

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TableTable 11. 11.TheThe bass bass ratio ratio values values measured measured in the in the eight eight mosques. mosques. Lalapaşa İvazpaşa Çeşnigir M. Attarhoca Göçbeyli Eğlenhoca Mahkeme Çarşı M. Lalapa¸saM. Ivazpa¸saM.˙ Çe¸snigirM. Attarhoca M. Göçbeyli M. E˘glenhoca Mahkeme M. Çar¸sıM. (MD) (MMD) M. (MD)(MMD) M. (MMD)(WFC) (MMD) M.(WDV) (WFC) M. (WDV)M. (WDF) M. (WDF)(WDF) M. (WDF) (WDF)(WDF) 1.21 1.34 1.16 1.08 1.15 0.96 0.95 1.13 1.21 1.34 1.16 1.08 1.15 0.96 0.95 1.13 4.2.3. EDT 4.2.3.EDT EDT is related to the early part of the decay process which measures the rate of sound decay EDTfor the is relatedfirst 10 todB the of earlydecay part [37]. of The the decayvalues process shouldwhich be within measures ±10% theof RT rate for of good sound acousticaldecay for conditions the ﬁrst 10 [34]. dB of The decay ratio [37 of]. EDT/T30 The values being should close be to within 1 is desirable±10% of RTfor forindoor good spaces.acoustical Additionally, conditions the [34 graph]. The in ratio Figure of EDT/T30 13 shows being the similarities close to 1 ison desirable the EDT forand indoor T30 valuesspaces. which Additionally, proves to thebe an graph indication in Figure of 13the shows diffuseness the similarities and directedness on the EDT of volumes and T30 [37].values At the which average proves ofto mid be anfrequencies, indication the of thevalues diffuseness of EDT/T30 and directednessranges are obtained of volumes as fol- [37]. lows:At the 1.05, average 1.02, 1.02, of mid respectively, frequencies, for the mosque valuess with of EDT/T30 masonry ranges ceilings, are and obtained 0.99, 0.97, as follows: 0.98, 1.00,1.05, 0.99, 1.02, respectively, 1.02, respectively, in the formosques mosques with with wooden masonry ceilings. ceilings, It is and seen 0.99, that 0.97, the 0.98, ratio 1.00, is close0.99, to respectively, 1 for all mosques. in the mosquesHowever, with in wooden wooden mosques, ceilings. the It is ratios seen thattend theto have ratio values is close closerto 1 forto 1. all It mosques. can be said However, that sound in woodendistribution mosques, is more the balanced ratios tend and to diffuse have valuesin mosques closer withto 1. wooden It can be ceilings. said that sound distribution is more balanced and diffuse in mosques with wooden ceilings.

3.00

2.50

2.00 ) S 1.50 EDT ( 1.00

0.50

0.00 125 250 500 1000 2000 4000

FREQUENCY (HZ) Lalapaşa M. (MD) İvazpaşa M. (MMD) Çeşnigir M. (MMD) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF) FigureFigure 13. 13. TheThe average average values values of of EDT EDT me measuredasured in in the the eight eight mosques. mosques.

4.2.4.4.2.4. D50 D50 D50,D50, which which is isrelated related to to speech speech intelligibility, intelligibility, is is expected expected to to be be greater greater than than 50%. 50%. The The optimumoptimum value value range range for for the the D50 D50 parameter parameter in in speech speech functional functional volumes volumes is is defined deﬁned as as 30–70%30–70% range range in in TS TS EN EN ISO ISO 3382-1. 3382-1. In In addition addition to to this, this, according according to to some some studies, studies, D50 D50 valuesvalues higher higher than than 20% 20% are are sufficient sufﬁcient for for vo volumeslumes with with music music and and speech speech functions functions [38,39]. [38,39 ]. AccordingAccording to to the the graph graph of of D50, D50, the the values obtained betweenbetween 20%20% and and 50% 50% in in the the recom- rec- ommendedmended ranges ranges (Figure (Figure 14 ).14). The The values values for for wooden wooden top-covered top-covered mosques mosques are are higher higher than thanmasonry-covered masonry-covered mosques. mosques. According According to the to average the average measured measured values values of D50, of wooden D50, woodencovered covered mosques, mosques, especially especially with wooden with domewooden or vaults, dome haveor vaults, better have speech better intelligibility speech intelligibilityfor worship for rituals. worship rituals.

Acoustics 2021, 4 FOR PEER REVIEW 17 Acoustics 2021, 4 FOR PEER REVIEW 17 Acoustics 2021, 3 574

0.60 0.60

0.50 0.50

0.40 0.40

0.30 0.30 D50 (%) D50 (%) 0.20 0.20

0.10 0.10

0.00 0.00 500 1000 2000 500 1000 2000 FREQUENCY (HZ) Lalapaşa M. (MD) FREQUENCYİvazpaşa M. (MMD) (HZ) Çeşnigir M. (MMD) Lalapaşa M. (MD) İvazpaşa M. (MMD) Çeşnigir M. (MMD) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF) Figure 14. The average values of D50 measured in the eight mosques. FigureFigure 14. 14. TheThe average average values values of ofD50 D50 me measuredasured in in the the eight eight mosques. mosques. 4.2.5. C80 4.2.5.4.2.5. C80 C80 C80 is defined as the ratio of first sound energy reaching within the first 80 ms to the C80C80 is isdefined defined as as the the ratio ratio of of first first sound sound en energyergy reaching reaching within within the the first first 80 80 ms ms to to the the late sound energy that comes to the receiver after this period of energy. The optimum latelate sound sound energy energy that that comes toto thethe receiver receiver after after this this period period of energy.of energy. The The optimum optimum value value range for mosques is recommended between −2 and +2 dB to satisfy music and valuerange range for mosques for mosques is recommended is recommended between between−2 and −2 +2and dB +2 to dB satisfy to satisfy music music and speech and speech activities in mosques [16]. speechactivities activities in mosques in mosques [16]. [16]. The acceptable C80 values are obtained in masonry-ceilinged mosques at an average TheThe acceptable acceptable C80 C80 values values are are obtained obtained in in masonry-ceilinged masonry-ceilinged mosques mosques at at an an average average of 500, 1000 and 2000 Hz (Figure 15). C80 averages obtained in masonry-ceilinged ofof 500, 500, 1000 andand 20002000 Hz Hz (Figure (Figure 15). 15). C80 C80 averages averages obtained obtained in masonry-ceilinged in masonry-ceilinged mosques mosques revealed that they are more suitable for musical rituals or Quran recitals. mosquesrevealed revealed that they that are they more are suitable more suitab for musicalle for musical rituals or ritual Qurans or recitals. Quran recitals.

5.00 5.00 4.00 4.00 3.00 3.00 2.00 2.00 1.00 1.00 0.00

C80 (DB) 0.00

C80 (DB) 500 1000 2000 -1.00 500 1000 2000 -1.00 -2.00 -2.00 -3.00 -3.00 -4.00 -4.00 FREQUENCY (HZ) FREQUENCY (HZ) Lalapaşa M. (MD) İvazpaşa M. (MMD) Çeşnigir M. (MMD) Lalapaşa M. (MD) İvazpaşa M. (MMD) Çeşnigir M. (MMD) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Attar Hoca M. (WFC) Göçbeyli M. (WDV) Eğlenhoca M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF) Mahkeme M. (WDF) Çarşı M. (WDF)

FigureFigure 15. 15. TheThe average average values values of of C80 C80 me measuredasured in in the the eight eight mosques. mosques. Figure 15. The average values of C80 measured in the eight mosques. 4.2.6. STI 4.2.6. STI 4.2.6. STISTI is an objective parameter used to measure speech intelligibility in a closed volume. STI is an objective parameter used to measure speech intelligibility in a closed vol- STISTI is evaluated is an objective in the parameter range of 0–1. used The to optimummeasure speech values intelligibility for STI are deﬁned in a closed as follows; volume. STI is evaluated in the range of 0–1. The optimum values for STI are defined as fol- ume.0–0.32 STI is is bad, evaluated 0.32–0.45 in the is poor, range 0.45–0.60 of 0–1. The is fair, optimum 0.60–0.75 values is good, for 0.75–1.0STI are defined is excellent as fol- [40]. lows; 0–0.32 is bad, 0.32–0.45 is poor, 0.45–0.60 is fair, 0.60–0.75 is good, 0.75–1.0 is excel- lows; 0–0.32According is bad, to the0.32–0.45 graph, is the poor, average 0.45–0.6 STI0 values is fair, of0.60–0.75 masonry is top-coveredgood, 0.75–1.0 mosques is excel- are lent [40]. lentobtained [40]. between 0.45–0.60, which is considered fair. In general, wooden top-covered

Acoustics 2021, 4 FOR PEER REVIEW 18

Acoustics 2021, 3 575 According to the graph, the average STI values of masonry top-covered mosques are obtained between 0.45–0.60, which is considered fair. In general, wooden top-covered mosques have higher STI values (Figure 1616).). This reveals a better speechspeech intelligibilityintelligibility level in wooden-covered mosques than masonry-coveredmasonry-covered ones, although it can be said that all the volumes have acceptable levels of speechspeech intelligibilityintelligibility by consideringconsidering their monumental features and function.

STI

Çarşı M. (WDF) 0.61 Mahkeme M. (WDF) 0.55 Eğlenhoca M. (WDF) 0.63 Göçbeyli M. (WDV) 0.62 Attar Hoca M. (WFC) 0.58 Çeşnigir M. (MMD) 0.51 İvazpaşa M. (MMD) 0.52 Lalapaşa M. (MD) 0.52

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

Figure 16. The average values of STI me measuredasured in the eight mosques.

4.2.7. Background Noise Level It is expected that background noise should be between suggested interval limits for good speech intelligibility.intelligibility. TheThe interval interval limits limits vary vary according according to to the the function function of of the the building. build- In the literature, NC25-30 is the recommended noise interval for religious buildings [41]. ing. In the literature, NC25-30 is the recommended noise interval for religious buildings Knudsen and Harris emphasized in their book that religious buildings have the necessity [41]. Knudsen and Harris emphasized in their book that religious buildings have the ne- for insulation from outside noise. The background noise of the inside shouldn’t exceed cessity for insulation from outside noise. The background noise of the inside shouldn’t 30 dB in worship buildings [42]. Acun and Yılmazer found that a quiet environment is exceed 30 dB in worship buildings [42]. Acun and Yılmazer found that a quiet environ- described as tranquil by users [27]. ment is described as tranquil by users [27]. Most of the mosques are located among noisy streets and surrounded by shops. How- Most of the mosques are located among noisy streets and surrounded by shops. ever, Göçbeyli Mosque and Lalapa¸saMosque are far from the city center and surrounded However, Göçbeyli Mosque and Lalapaşa Mosque are far from the city center and sur- by elements of a quiet environment such as a cemetery, trees, and dwellings. The mean rounded by elements of a quiet environment such as a cemetery, trees, and dwellings. The LAeq values inside and outside for each mosque are listed in Figure 17. According to the mean LAeq values inside and outside for each mosque are listed in Figure 17. According graph, all mosques in the study, except the Ivazpa¸saMosque˙ and Mahkeme Mosque, which toslightly the graph, exceeded all themosques recommended in the study, limit valueexcept for the background İvazpaşa noiseMosque level, and are Mahkeme obtained Mosque,to have values which below slightly 30 dbA.exceeded It has the been recommended recognized that limit the value noise for level background outside has noise little level,effect are on obtained the indoor to environmenthave values below in the 30 examined dbA. It has mosques. been recognized It can be that related the noise to design level outsidecriteria ofhas historical little effect mosques, on the suchindoor as wallenvironment thicknesses in ofthe mosques, examined garden mosques. walls It and can thebe relatedbuilding tomaterials design criteria used, of which historical all help mosque to creates, such suitable as wall acoustic thicknesses conditions of mosques, inside. gar- On denthis issue,walls and it is importantthe building to lookmaterials at historical used, whic mosquesh all help regarding to create noise suitable control acoustic between con- the ditionsinside andinside. the On outside this issue, for the it futureis important projects. to Inlook addition at historical to this, mosques the differences regarding between noise controlthe sound between levels the measured inside and on the the inside outside and for outside the future were projects. similar forIn addition the mosques. to this, the differences between the sound levels measured on the inside and outside were similar for the mosques.

AcousticsAcoustics 20212021, 4, 3FOR PEER REVIEW 19576

70 60 50 40 30 20 10 0 Lalapaşa İvazpaşa Çeşnigir Attar Göçbeyli Eğlenhoca Mahkeme Çarşı M. Background Noise Level dB(A) Level Noise Background M. (MD) M. (MMD)M. (MMD) Hoca M. M. (WDV) M. (WDF) M. (WDF) (WDF) (WFC) main prayer hall courtyard

Figure 17. The background noise levels from indoor and courtyard of mosques. Figure 17. The background noise levels from indoor and courtyard of mosques. 5. Discussion 5. DiscussionMosques are expected to create the ideal environment for both speech and music. MostMosques studies are conclude expected that to long create reverberation the ideal environment time inside mosquesfor both isspeech expected and bymusic. being Mostcompared studies to conclude the classical that speechlong reverberation rooms. However, time inside while mosques it is appropriate is expected to evaluate by being the comparedparameters to the related classical to speech speech for rooms. situations Howeve wherer, thewhile intelligibility it is appropriate of speech to evaluate is important the parametersduring rituals related such to as speech sermons, for itsituations is stated inwher variouse the studiesintelligibility that a reverberant of speech is environment important duringis preferred rituals insuch mosques as sermons, so that it theis stated desired in various spiritual studies atmosphere that a canreverberant be experienced environ- by mentthe worshipers.is preferred in mosques so that the desired spiritual atmosphere can be experienced by the worshipers. 5.1. The Acoustic Evaluation of Mosques 5.1. TheAlthough Acoustic Evaluation there is a of lack Mosques of certain acoustic data that are speciﬁcally oriented to mosquesAlthough (masjids) there [11is ],a thelack acoustic of certain requirements acoustic data for achievingthat are specifically the desired conditionsoriented to in mosquesthe prayer (masjids) hall of [11], the mosques the acoustic are summarizedrequirements as for follows achieving [43]; the desired conditions in the- prayerlower hall but of controlled the mosques RTs are for summarized mid and high as frequencies, follows [43]; in comparison to low frequen- - lowercies, forbut thecontrolled intelligibility RTs for of sermons;mid and high frequencies, in comparison to low fre- - quencies,higher butfor the controlled intelligibility RTs for of lowsermons; frequencies, in comparison with mid and high - higherfrequencies, but controlled to enhance RTs for the low spiritual frequencies, aspects in of comparison musical rites with and mid to balanceand high sound frequencies,absorption to enhance of interior the surface spiritual materials aspects over of musical the frequency rites and range; to balance sound ab- - sorptionMinimal of acousticalinterior surface defects ma suchterials as soundover the glare, frequency echoes, range; and dead spots; - - MinimalLow background acoustical noisedefects that such does as notsound hide glare, or reduce echoes, speech and dead intelligibility. spots; - LowAccording background to Orfali noise (2007);that does “High not hide Reverberation or reduce speech Time willintelligibility. lead to unacceptable intelligibilityAccording levels,to Orfali while (2007); low “High reverberation Reverberation time will Time result will in lead so calledto unacceptable “dead” spaces in- telligibilitywhere spiritual levels, ceremonies while low losereverberation the attention time of will the result worshippers.” in so called [10]. “dead” In Sü Gülspaces and whereÇalı¸skan’sstudy, spiritual ceremonies the acoustical lose characteristicsthe attention of of the prayerworshippers.” hall are described:[10]. In Sü “AlthoughGül and Çaltheışkan’s speech study, intelligibility the acoustical is the characteristics upmost priority; of the a mosqueprayer hall is not are a described: classical speech “Although room theas speech a conference intelligibility hall or is auditorium.the upmost priority The acoustical; a mosque environment is not a classical of a speech mosque room should as a satisfyconference the spiritualhall or auditorium. aspects of worship The acoustic whileal enablingenvironment the most of a propermosque environment should satisfy for thethe spiritual perception aspects of theof worship imam and while muezzin enablin conveys.g the most The proper functional environment space offor athe mosque per- should not be acoustically dull, as well as not excessively reverberant” [44]. Elkhateeb ception of the imam and muezzin conveys. The functional space of a mosque should not et al. proposed a model for the optimum RT values: “There is much evidence to prove be acoustically dull, as well as not excessively reverberant” [44]. Elkhateeb et al. proposed that long reverberation inside masjids is recommended because it enhances its spiritual a model for the optimum RT values: “There is much evidence to prove that long reverber- role, whereas a short reverberation is neither functional nor reasonable. It appears that the ation inside masjids is recommended because it enhances its spiritual role, whereas a short optimal reverberation curve suggested by Kayılı, is the most appropriate. Values on this reverberation is neither functional nor reasonable. It appears that the optimal reverbera- curve compromise the wishes of Imams and the requirements of the worshippers” [11]. tion curve suggested by Kayılı, is the most appropriate. Values on this curve compromise Within the context of this study, the results obtained from the acoustical measurements the wishes of Imams and the requirements of the worshippers” [11]. of mosques for the relevant frequency ranges and the optimum parameter value ranges Within the context of this study, the results obtained from the acoustical measure- compiled from references for this volume range are brought together in Table 12. According ments of mosques for the relevant frequency ranges and the optimum parameter value to the table, it can be said that there are differences in values depending on whether the rangesmaterial compiled of the ceilingfrom references structure isfor wood this vo orlume masonry. range are brought together in Table 12.

AcousticsAcousticsAcoustics 2021Acoustics 2021, Acoustics42021 FORAcoustics, 4 ,FOR2021 4 AcousticsPEERAcoustics FOR 2021 ,PEER 4 2021 FOR PEERREVIEW, 4 ,2021REVIEWFOR2021 4PEER FORREVIEW, , PEER 4 4 FORREVIEWPEERFOR REVIEW PEERPEER REVIEW REVIEWREVIEW 20 20 20 20 20 20 2020

AcousticsAcoustics 2021 2021, ,4 4 FOR FOR PEER PEER REVIEW REVIEW 2020

AccordingAccordingAccordingAccording toAccording Accordingtothe tothe AccordingAccording table,the totable, thetable,to itto the cantable,it the toit cantotable, be canthetable,the it besaid can betable, table,itsaid it can saidthatbe can that ititsaidbe thattherecancanbe saidthere that said betherebe are that saidsaid aretherethat differences are there differencesthat thatthere aredifferences there aretheredifferences are differencesin are differences areinvalues in valuesdifferencesdifferences values in depending valuesin depending in valuesdepending values inin depending valuesvalues ondepending dependingon on dependingdepending on on on onon Acoustics 2021, 3 577 whether thewhetherwhether materialwhether the the ofmaterial materialthe materialceiling of of the structurethe ofceiling ceilingthe ceiling structureis structure wood structure or is ismasonry.wood wood is woodor or masonry. masonry. or masonry. AccordingAccordingwhetherwhether to whethertothe thethe material the table,table, materialwhetherthe it materialitof can canthe ofthe beceilingbe the materialof saidsaid ceilingthe structure that thatceiling of structure therethere the structure is ceiling are arewood is differencesdifferences wood structure isor woodmasonry. or masonry. inorisin woodvaluesmasonry.values or dependingdepending masonry. onon whetherwhether the the material material of of the the ceiling ceiling structure structure is is wood wood or or masonry. masonry. TableTableTable 12. 12. TableThe 12. TheTable measured TableThe 12. measured TableThe12.measuredTable 12. The measured valuesThe 12.12. measuredvalues Themeasured Thevalues of measured measured valuesacousticalof of acousticalvalues acousticalvalues of acousticalvalues valuesofparameters of acousticalparameters acoustical parameters ofof acoustical acousticalparameters in parameters eighinparameters ineigh t parameters parameterseighmosques int mosques eight inmosques ineight eighmosquesand inint and mosques eightrecommendedeigh andmosques recommendedtt and recommendedmosquesmosques and recommended and recommended andrecommendedvalues.and values. recommendedrecommended values. ( values. ( (values. masonry values. masonry ( masonry values.values. ( (top- masonry top- masonry (( top- masonry top- masonry masonry toptop- top-top- coveredcoveredcovered mosquescovered mosquescovered mosquescovered mosques covered covered mosques woodenmosques wooden mosques mosqueswooden top-covered wooden top-covered wooden top-covered wooden top-covered woodenwooden mosques)top-covered top-coveredmosques) mosques) top-coveredtop-covered mosques). .mosques) .mosques) .mosques)mosques) . . .. TableTableTable 12. The12. 12. The The measured measured measured values values values of of acousticalof acoustical acoustical parameters parameters parameters in in in eight eigh eight mosquest mosques mosques andand and recommended recommended values. values.values. ( ( ( masonry masonry toptop- covered mosques wooden top-covered mosques). top-coveredcovered mosques,mosquesMASONRYMASONRYMASONRY MASONRYwooden wooden TOP-COVEREDMASONRY MASONRYTOP-COVERED TOP-COVERED top-coveredMASONRY MASONRYtop-covered TOP-COVERED TOP-COVERED TOP-COVERED mosques). TOP-COVEREDTOP-COVERED mosques) . WOODEN WOODEN WOODEN WOODEN TOP-COVERED WOODEN TOP-COVERED WOODEN TOP-COVERED WOODEN WOODEN TOP-COVERED TOP-COVERED TOP-COVERED TOP-COVEREDTOP-COVERED

LMMASONRYMASONRYLM LM LM TOP-COVERED LM TOP-COVEREDİLMM İ M LMLMİ MMASONRY İM İM İM ÇM TOP-COVEREDÇMİİ MMÇM ÇMÇM AHMÇM AHM ÇMAHMÇM AHM AHMGMMAHM WOODEN WOODENGMM AHMAHMGMM GMM TOP-COVERED WOODENGMMTOP-COVEREDGMM EM GMMEMGMM EM TOP-COVERED EM EMMMEM MM EMEMMM MM MM MMÇM ÇMMM MMÇM ÇMÇM ÇM ÇMÇM LM IM˙ ÇM AHM GMM EM MM ÇM LMRECOMMENDED İM ÇM AHM GMM EM MM ÇM PARAMETERS LM İM ÇM AHM GMM EM MM ÇM RANGES

T30 0.7–1.1 [10]

1.99 1.97 1.95 1.52 1.27 1.15 1.48 1.26

(500–1000 Hz) 1.991.75–1.91.99 1.99 [14 1.99] 1.99 1.971.99 1.97 1.991.971.99 1.971.97 1.97 1.95 1.97 1.951.97 1.95 1.95 1.95 1.951.52 1.52 1.95 1.951.52 1.521.52 1.271.52 1.27 1.521.521.27 1.271.27 1.271.15 1.15 1.271.271.15 1.151.15 1.151.48 1.48 1.151.151.48 1.481.48 1.481.26 1.26 1.481.481.26 1.261.26 1.26 1.261.26 1.2< excellent Bass ratio 1.21 1.34 1.16 1.08 1.15 0.96 0.95 1.13 1.991.991.21 0.9> 1.21 poor1.21 [36 1.21]1.971.971.21 1.34 1.21 1.34 1.211.341.21 1.34 1.951.34 1.951.34 1.16 1.34 1.161.34 1.16 1.161.521.52 1.16 1.161.08 1.08 1.16 1.161.08 1.081.271.271.08 1.15 1.08 1.15 1.081.081.15 1.151.151.151.15 1.150.96 0.96 1.151.150.96 0.961.481.480.96 0.960.95 0.95 0.960.960.95 0.951.261.260.95 0.951.13 1.13 0.950.951.13 1.131.13 1.13 1.131.13 RT − (%10x RT) ≤ EDT 1.79 < 2.09 1.77 < 2.02 1.75 < 1.98 1.37 < 1.5 1.14 < 1.24 1.04 < 1.13 1.33 < 1.49 1.13 < 1.25 1.21EDT ≤RT + (%10x1.34 1.16 1.08 1.15 0.96 0.95 1.13 (500–1000 Hz) 1.21 1.34 < 2.19 1.16 < 2.17 1.08<1.37 2.141.37 <1.37 < 1.37 < 1.15<1.37 < 1.681.141.37 <1.14 1.37<1.37< 1.14 < < <1.14 < 1.40 0.961.14 <1.14 1.04 <1.04 1.141.14< 1.04 < 1.27< << 1.04 < 0.951.04 <1.04 1.33 <<1.33 1.04 1.631.04<1.33 < << 1.33 < 1.131.33 <<1.33 1.13 1.38 <1.13 1.33 1.33< <1.13 < << 1.13 < 1.13 <1.13 < 1.131.13< << 1.791.79 <1.79 RT)2.09 < 2.09 [1.7934< 2.09] 1.79 <1.771.79 2.09 1.77< < 2.091.791.771.79< 2.02 2.09< 2.02 1.77<< 2.09 2.022.091.77 < 1.77 2.021.75 <1.75 2.021.771.77< < 1.752.02 1.98 < << 1.98 1.75 2.02<2.02 < 1.98 1.75 < < 1.75 1.98< < 1.981.751.75< < 1.98 << 1.98<1.98 << −4< < 0 dB; for 1.51.5 1.5 1.51.241.5 1.24 1.51.241.5 1.241.241.13 1.13 1.241.24 1.13 1.131.131.49 1.49 1.131.13 1.49 1.491.491.25 1.25 1.49 1.49 1.25 1.251.25 1.251.25 C80 1.37 < 1.51.14 < 1.241.04 < 1.131.33 < 1.491.13 < 1.25 1.79 << 2.09 2.19< music2.19 < 2.19 1.77< 2.19< < < 2.19< 2.02 2.17 2.19< 2.17 << 2.192.172.19 <1.75 2.17< 2.17< 1.982.172.14 <<2.14 2.17<2.17 2.14 2.141.372.14 2.14< 2.142.14 1.14 < 1.04 < 1.33 < 1.13 < (500–1000–1.79 < 2.09 1.77 < 2.02 −0.601.75 < 1.98−0.63 < −1.41< 1.68 <1.60 1.68< 1.68< 1.40< 1.68 2.39 < 1.40< 1.40< <1.27 1.403.36 < 1.27< 1.27< 0.86 <1.63 1.27 < 1.63<2.57 1.63< <1.38 1.63 < 1.38< 1.38 < 1.38 −2< <+2 dB for 1.5< 1.68 < 1.68< 1.681.24< 1.40 << 1.68 1.40< 1.401.13 < 1.27 < < 1.40 1.27< 1.271.49 < 1.63 < < 1.27 1.63< 1.631.25 < 1.38 < <1.63 1.38< 1.38 < 1.38 2000 Hz) < 2.19 < 2.17 2.14 1.5 1.24 1.13 1.49 1.25 < 2.19 speech [6]< 2.17 2.14 < 1.68 < 1.40 < 1.27 < 1.63 < 1.38 D50 -0.60 -0.60-0.60-0.63 -0.60 -0.63 -1.41-0.63 < 1.68 -1.41 1.60 -1.41 < 1.401.60 2.39 1.60 < 1.272.39 3.36 2.39 < 1.633.36 0.86 3.36 < 1.380.86 2.57 0.86 2.57 2.57 -0.600.3< <0.7-0.60 [33-0.60 ] -0.63 -0.60-0.63-0.63 -0.63 -1.41 -0.63 -1.41 -1.41 -1.41 1.60 -1.41 1.60 1.601.60 2.39 1.602.39 2.392.39 3.36 2.393.36 3.363.36 0.86 3.360.86 0.860.86 2.57 0.862.57 2.572.57 2.57 (500–1000– 0.37 0.36 0.30 0.46 0.47 0.54 0.38 0.49 0.2 < [38,39] 2000 Hz) -0.60-0.600.37 0.37 0.37 0.37-0.63-0.630.37 0.36 0.37 0.36 0.370.360.37 0.36 -1.410.36 -1.410.36 0.30 0.36 0.300.36 0.30 0.301.601.60 0.30 0.300.46 0.46 0.30 0.300.46 0.462.392.390.46 0.47 0.46 0.47 0.460.460.47 0.473.363.360.47 0.470.54 0.54 0.470.470.54 0.540.860.860.54 0.540.38 0.38 0.540.540.38 0.382.572.570.38 0.380.49 0.49 0.380.380.49 0.490.49 0.49 0.490.49 0.00–0.30 (bad); 0.370.370.30–0.450.52 0.52 0.52 (poor); 0.520.360.360.52 0.52 0.52 0.52 0.520.52 0.52 0.300.52 0.300.52 0.51 0.52 0.510.52 0.51 0.510.460.46 0.51 0.510.58 0.58 0.51 0.510.58 0.580.470.470.58 0.62 0.58 0.62 0.580.580.62 0.620.540.540.62 0.620.63 0.63 0.620.620.63 0.630.380.380.63 0.630.55 0.55 0.630.630.55 0.550.490.490.55 0.550.61 0.61 0.550.550.61 0.610.61 0.61 0.610.61 0.45–0.60 STI 0.520.5227.9 (medium);27.9 27.9 27.90.520.5227.9 30.8 27.9 30.8 27.930.827.90.52 30.8 0.5130.8 0.5130.8 29.1 0.52 30.8 29.130.8 29.1 29.10.580.58 29.1 0.51 29.1 27 27 29.1 29.1 27 270.620.62 0.58 27 28.2 27 28.2 28.227 27 28.20.620.630.63 28.2 28.228.1 28.1 28.2 28.228.10.63 28.10.550.5528.1 28.130.5 0.5530.5 28.128.130.5 30.50.610.6130.5 0.6130.524.4 24.4 30.530.524.4 24.424.4 24.4 24.424.4 0.60–0.75 (good); 27.9 0.75–1.00 30.8 29.1 27 28.2 28.1 30.5 24.4 27.9(excellent) [4030.8] 29.1 27 28.2 28.1 30.5 24.4 Background 5.2.5.2. The5.2. The Evaluation 5.2.The Evaluation5.2. TheEvaluation5.2. The Evaluation 5.2.The5.2. in Evaluation TermsinTheEvaluationThe inTerms EvaluationEvaluationTerms inof Termsthe ofin ofinthe TermsEffect theTerms Effect ofinin Effect the sTerms Terms ofof s of theEffect Architecturalof sthe ofArchitectural Effectofof ArchitecturalEffects thethe of s ArchitecturalEffectEffect ofs ofArchitectural Features Architecturalss ofFeaturesof ArchitecturalFeaturesArchitectural onFeatures on theFeatures on Featuresthe Acoustic the on AcousticFeaturesFeatures Acoustic theon on theAcoustic the ononAcoustic Acoustic thethe AcousticAcoustic <30 dbA [6] 27.9 30.8 29.1 27 28.2 28.1 30.5 24.4 Noise Level EnvironmentsEnvironmentsEnvironments Environments 5.2.5.2.Environments The The Evaluation EnvironmentsEvaluationEnvironments in in EnvironmentsTerms Terms of of the the Effect Effect ss of of Architectural Architectural Features Features on on the the Acoustic Acoustic EnvironmentsEnvironmentsWhenWhenWhen theWhen the average theWhen averageWhen averagetheWhenWhen thevaluesaverage the values average values averagethethe of values average averagereverberationof valuesofreverberation values reverberation of values valuesreverberation of of reverberation reverberationtimes ofof times reverberationreverberation times for timesfor mid for timesmid times frequenciesmidfor frequencies times timesformid frequencies for mid frequencies mid forfor frequenciesare mid midfrequencies are examined, are frequenciesfrequencies examined, examined,are areexamined, are it examined, itexamined,areare it examined,examined, it it it itit 5.2. The Evaluationis seen that inis Termsis seenthe seen ismosques that ofseen that the the Effectsthatthe mosqueswith mosquesthe of masonrymosques Architectural with with masonrytops with masonry Features have masonry tops reached tops on have thetops have Acoustichigher reachedhave reached reachedvalues Environments higher higher than higher values values the values woodenthan than the than the wooden woodenthe wooden isWhen Whenseenis seenthat the isthe seen theaverage thataverage mosquesthat theis seenmosquesvalues thevalues mosques thatwith of of the withreverberation masonryreverberation mosques with masonry masonry tops with timestopshavetimes masonrytops have reachedfor for havemid midreached tops frequencies higherreachedfrequencies have higher values higherreached arevalues are than examined, valuesexamined, higher thanthe thanwooden the values it it woodenthe woodenthan the wooden Whenones. the averageWhileones.ones. the values ones.While Whilemasonry ofWhile the reverberationthe masonrycovered themasonry masonry mosquescovered timescovered covered for mosqueshave midmosques mosques frequencieshigher have have values higherhave higher are forhigher examined, values valuesthe valuesspeech for for it the theforrituals, speech thespeech speech rituals, rituals, rituals, isis seen seenones. that thatones. While the ones.the While mosques mosquesthe While masonryones.the with themasonrywith While masonry masonry coveredmasonry the covered masonry covered mosquestops tops mosques havehave coveredmosques havereached reached have higher mosques havehigher higherhigher values higher values values havevalues for values higherthan than thefor the speechtheforthe values wooden woodenthespeech rituals, speechfor rituals,the rituals, speech rituals, is seen thatwooden the mosques mosqueswoodenwooden withwooden mosqueshave masonrymosques mosquesreached have topshave morereached have reached reachedsuitablereached more more highervaluesmoresuitable suitable suitable valuesfor values valuesthis than values function.for for the this woodenthisfor function. Moreover, thisfunction. function. Moreover, Moreover,the Moreover, the the the ones.ones.wooden WhileWhilewooden wooden mosques thethe mosquesmasonrymasonry woodenmosques have coveredhave coveredreached mosques have reached mosques mosquesreachedmore have more suitable reachedmorehavehave suitable highersuitablevalueshigher more values valuesfor valuesvaluessuitable thisfor for forforfunction.this values thethe thisfunction. speechspeech function.for Moreover, this rituals,Moreover,rituals, function. Moreover, the the Moreover, the the ones. Whilelower the reverberation masonrylowerlower lowerreverberation coveredreverberation times reverberation mosquesin woodentimes times timesin have in mosqueswooden wooden higherin wooden mosquesindicate valuesmosques mosques forthatindicate indicate the there indicate speech that isthat a there dry that rituals,there environmentisthere isa adry isdry aenvironment dryenvironment environment woodenwoodenlowerlower mosquesmosquesreverberationlower reverberation reverberation havehavelower times reachedreached reverberation times in times wooden moremore in wooden in suitablesuitable timeswoodenmosques mosques in valuesvalues woodenmosques indicate forindicatefor mosques thisindicatethatthis function.thattherefunction. thatindicate there is athere Moreover, Moreover,dryis thata isenvironmentdry athere dryenvironment thethe environmentis a dry environment wooden mosquesfor musical haveforfor rituals.musical musical reachedfor musical In rituals. therituals. more grouprituals. 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It Itis ob- isclearly Itclearly is clearly ob- ob- ob- forfor doesn’t musicalmusicaldoesn’t revealdoesn’t rituals.rituals. reveal significant InrevealIndoesn’t thesignificantthe groupsignificantgroup reveal differences of ofdifferences significant woodenwooden differences in the ceiling ceiling indifferences reverberationthe in mosque,themosque,reverberation reverberation in the thetime variationreverberationvariation timevalues. time values. in inItvalues. theisthe time Itclearly ceiling ceilingis It values.clearly is ob- clearly ob-It is ob- clearly ob- musical rituals.served In that theservedserved the group servedT30 that that of values the wooden thatthe T30 T30varythe values ceiling T30values according values vary mosque, vary a varyccording toaccording the the a ccordingmaterial variation to to the the toofmaterial in materialtheceiling. the material ceiling of of ceiling. ceiling.doesn’t of ceiling. doesn’tdoesn’tserved servedrevealreveal thatserved thethatsignificantsignificant T30that theserved valuesT30the differences differencesT30 valuesthat vary values the varya T30ccording invaryin avalues ccording thethe a ccording reverberationtoreverberation vary the to material athe ccordingto materialthe time materialtimeof toceiling. values.ofthevalues. ceiling. materialof ceiling. 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Just 1.26.1.48,1.48, 1.26.Just Just1.26. 1.26. Just Just Just AccordingAccording to the to T30the T30 results, results, masonry masonry covered covered mosques mosques have have values values as 1.99, as 1.99, 1.97, 1.97, 1.95noticeable andnoticeablenoticeable woodennoticeable differencenoticeable differencenoticeable covereddifferencenoticeablenoticeable difference fordifference mosquesfordifference T30 for T30differencedifference hasT30for has for haveT30specified hasfor specifiedT30 has specifiedT30forforthe has specifiedT30T30 averageshasto specified to behashasspecified to be5% bespecified specified to5%as (0.1 5% be to1.52,(0.1 to s)5%be(0.1 be s)in1.27,to to5% (0.1 s) in5% thebebe in(0.1 the1.15, s) 5%(0.1 literature5%the in s)literature (0.1 (0.1 1.48,s)theliteraturein in thes)s)literature 1.26.the [44].inin literature [44]. theliteraturethe [44].JustIn literature literature Inthe[44]. Inthe [44]. the[44].In the In[44].[44]. In the the InIn thethe 1.951.95 and and wooden wooden covered covered mosques mosques have have the averagesthe averages as 1.52, as 1.52, 1.27, 1.27, 1.15, 1.15, 1.48, 1.48, 1.26. 1.26. 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However,havehavehave a completelyitahave iscompletelya havecompletelyexpected havea completely haveahave acompletelydifferent completely that different aa different completelycompletely someone different perception differentperception differentperception coming differentdifferentperception ofperception perception ofthe out of theperceptionperception environment the ofof environment the theenvironmentof of themasonryenvironment the ofof environment theenvironmentthewhen when coveredenvironment environmentwhen you whenyou youenter whenmosque whenenter you enter a whenwhenyou woodenenterayou will woodena enter you woodenyou entera wooden enterentera awooden wooden aa woodenwooden However,However, it is expectedit is expected that someone that someone coming coming out of theout masonry of the masonry covered mosquecovered willmosque have will havemosque. mosque.a mosque.completelymosque. mosque. mosque. different mosque.mosque. perception of the environment when you enter a wooden a completelyhave a completely different perception different perception of the environment of the environment when you enter when a woodenyou enter mosque. a wooden mosque.Masonry-covered Masonry-coveredMasonry-coveredMasonry-coveredMasonry-coveredMasonry-coveredMasonry-coveredMasonry-covered mosques mosques mosques mosques have mosqueshave mosqueshave higher mosques mosqueshigherhave higher have T30 havehigher T30 vahigherhaveT30have higherluesva T30values higherhigher luesinT30 va T30 inbasslues va in bass T30T30va lues bassfrequencies inlues vafrequenciesva bass infrequencieslues luesin bass frequenciesbass inin frequencies thanbassbass frequencies than than frequenciesinfrequencies in midthan inmid than mid thanin mid in thanthan in mid mid inin mid mid mosque.Masonry-covered mosques have higher T30 values in bass frequencies than in mid frequencies,Masonry-coveredfrequencies,frequencies,frequencies,frequencies, andfrequencies, and bassfrequencies,andfrequencies, bass mosques and bassratios andratios bass andratios implybass andhave andratiosbassimply imply ratios bassbass thehigherratios implythe feeling ratiostheratiosimply feeling imply T30feelingthe imply implyof thefeelingva theofwarmthlues feeling ofwarmth feelingthethe warmth inof feelingfeeling bass warmthwhichof of whichwarmth whichfrequencieswarmth of ofis whichwarmth warmthtois istowhichbe which to beensured is be thanensuredwhichtowhich is ensured beisto in to ensuredbeindoors. is is midbe indoors. ensuredtoto indoors.ensured bebe indoors.ensuredensured indoors. indoors. indoors.indoors. frequencies,Masonry-covered and bass ratios mosques imply the have feeling higher of warmthT30 values which in bass is to frequencies be ensured indoors.than in mid frequencies,TheThe lineThe line Theofline and TheofT30 lineThe ofbassT30 lineformsT30 The Theof line formsratios T30offorms lineline of anT30 forms T30 animply almostofof an forms almost T30T30forms almostan the formsflat formsanalmost feelingflatan linealmostflat almost anlinean flatinline ofalmostalmost inthe flatwarmth line inflatthe transitionlinethe inflatlineflattransition thetransition in which linelinein thetransition the fromin in transition is fromthetransitionthe tofrom low betransitiontransition lowfrom ensuredfrequencieslow from frequencies from lowfrequencies fromlowfrom indoors. frequencieslow frequencies tolow lowfrequencies tomid tofrequenciesmidfrequencies mid to mid to to mid mid toto mid mid Thefrequencies, line of T30 formsand bass an ratios almost imply flat line the infeeling the transition of warmth from which low isfrequencies to be ensured to midindoors. Thefrequencies linefrequenciesfrequencies of frequenciesT30 frequenciesin frequenciesforms inwooden-covered infrequenciesfrequencieswooden-covered wooden-coveredanin almostwooden-coveredin in wooden-covered wooden-covered inin flat wooden-coveredwooden-coveredmosques. linemosques. mosques. in mosques.the Ther mosques. transitionThermosques. 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It mosques. isItmosques. seenisIt isseenmosques.mosques. seenthat Itthat Itisthethat is seenthe ItdistributionItseen the is isdistribution that seen seendistribution that the that thatthe distribution of distributionthethe ofsound ofdistributionsounddistribution sound energy ofenergy ofenergysound sound is ofof balanced is soundsound energyisbalanced energy balanced energyenergy isfor is balancedfor sixbalanced for isissix mosques. balancedbalancedsix mosques. mosques.for for six six forfor mosques. mosques. six six mosques.mosques. 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C80 C80 averagesshow C80averages averages show show show masonrymasonryAccording ceilingsAccordingmasonrymasonry ceilings provide toto ceilings thethe masonryprovideceilings the graphgraph appropriateprovide theofprovide ofceilings C80 C80appropriate the values, values,appropriate conditionstheprovide appropriate it itcondit canthecan for conditappropriate bebeions music saidconditsaid forions that rituals.that musicions for condit mostmost musicfor rituals. C80 music ofionsof averagesrituals. thethe C80for rituals. mosquesmosques music averagesC80 show C80 averages rituals. withwith averages show C80 show averagesshow show that all masonrythatthat all thatall masonrymosques masonry all masonry mosquesprovide mosques mosques a provide suitable provide provide a living suitablea suitable a environmentsuitable living living livingenvironment environment for environment music for function, for music music for music function,while function, function, while while while thatmasonry allmasonrythat masonry allthat ceilings ceilings masonrythat all mosques masonry all provide provide masonry mosquesthat provide mosquesall the the masonrymosques provideappropriate appropriate a suitable provide mosquesaprovide suitable living condit condita suitable aprovide environment livingsuitableionsions livingfor for environment a music livingmusicsuitable environment for environmentrituals. rituals. music living for function,C80 C80music environment for averages averages musicfor function, music while function, show show for function, while music while function, while while values of valueswoodenvaluesvalues of of mosqueswooden wooden of wooden mosquesare mosques obtained mosques are are obtainedabov obtainedaree obtained 0 as abov abovbeinge abov 0e dryas0 as ebeing spaces.0being as beingdry dry The spaces. dryspaces. values spaces. The Theof valuesD50 Thevalues values of of D50 D50 of D50 valuesthatthat ofvalues all all wooden masonry masonryvalues ofvalues wooden mosquesof mosques mosqueswooden ofvalues woodenmosques are provide providemosques of obtained mosqueswooden are a aobtained suitable aresuitable above mosques obtainedare obtained 0living abovliving as being areabove environment environment0 obtainedasabove dry being0 ase spaces. 0 being asabovdry for beingfor spaces. Thedrye music music 0 asdry valuesspaces. being function, Thefunction,spaces. ofvaluesThe dry D50 The valueswhile spaces.while of values D50 of The D50 of values D50 of D50 havevaluesvalues been foundofof woodenwooden in the mosquesmosques appropriate areare obtainedobtained range in abov allabov mosques.ee 00 asas beingbeing However, drydry spaces.spaces. this parameter TheThe valuesvalues has ofof D50D50 reached higher values in wooden-ceilinged mosques, and it seems that speech intelligibility

is better than masonry-ceilinged mosques.

Acoustics 2021, 3 578

The differences in background noise levels for eight mosques are obtained as similar between inside and outside. This analysis was carried out to observe the behavior of the building envelope for sound transmission between the indoor and outdoor environment. In these examples, where the building walls were built with a masonry system and the interior surface materials are similar, the ceiling material and shape differ. Despite this, it can be said that mosques with different types of ceilings do not create great differences in sound transmission behavior, and almost all mosques behave similarly. According to the evaluation results, it has been determined that the values of acoustical parameters of the mosques show different behaviors concerning the ceiling types. The wooden-ceilinged mosques seem to be more appropriate for rituals with speech functions such as Friday’s sermon or informative speech from the lecture chair. However, masonrycovered mosques have a better acoustical environment for musical activities such as the recital of the musical version of the Holy Quran. However, it should also be stated that they are important examples of architectural history and have their own characteristics and re- ﬂect that the communities were using them to experience different acoustical environments, but none of them are far away from the decent limits.

6. Conclusions Although acoustical parameter values of cases are different depending on the typology of the examined mosques, it is determined that all of them are in the acceptable range. On the other hand, it can be concluded that there will be differences in the user perceptions of the praying halls depending on the acoustical ambiance. This is because the differences between the values of acoustical parameters are above the JND range, when the mosques are compared. In addition, it is found that the material of the ceiling construction has more singular effect than its formation on acoustic characteristics of the sound volume. While reverberant environments are more appropriate for creating the desired sacred feeling, in some cases, short reverberation times and good speech intelligibility are desired during rituals such as Friday sermons or praying. In other words, acoustic evaluation of the mosque volume is quite a difficult process because of the challenge between T30 requirements of the intelligibility of speech and the need of sacred feeling. While these debates continue for the reverberation time values in mosques, the acoustic environments in historical mosques that have been used for centuries have been accepted as they are by people that use them. Electro-acoustic reinforcement can be used as a solution in wooden- ceilinged mosques with low reverberation times, in accordance with the recommendations of acoustic consultants, to create the vitality of the volume and spiritual feeling for rituals with musical functions such as Quran recitals or hymns. However, it should be kept in mind that musical instruments are not included in these sermons. Another important aspect of the study is to emphasize the preserving and sustaining the original acoustical perception of the historical volumes. In the context of the importance of evaluating the intangible values specific to societies as cultural heritage in terms of diversification and enrichment of cultural heritage, the genuine acoustic environment of mosques is an issue that should be taken into consideration in renovation studies. In the renovation works of historical mosques, it is necessary to consider the unique acoustic perceptions of the volumes rather than the architectural features of the mosques. It is important to choose suitable and sustainable materials, especially in the renovation of historical mosques, to sustain rituals with speech and musical functions without harming the original acoustic environment of the prayer hall. Finally, it can be said that increasing the number of studies in which acoustic comfort conditions of mosques are analyzed by subjective evaluation methods and evaluating the data obtained from such studies together with objective findings are expected to be developed in this field. Acoustics 2021, 3 579

Author Contributions: Conceptualization, F.Y.S. and Ö.Y.K.; methodology, F.Y.S. and Ö.Y.K.; software, F.Y.S. and Ö.Y.K.; validation, F.Y.S. and Ö.Y.K.; formal analysis, F.Y.S. and Ö.Y.K.; investigation, F.Y.S. and Ö.Y.K.; resources, F.Y.S. and Ö.Y.K.; data curation, F.Y.S. and Ö.Y.K.; writing—original draft preparation, F.Y.S. and Ö.Y.K.; writing—review and editing, F.Y.S. and Ö.Y.K.; visualization, F.Y.S. and Ö.Y.K.; supervision, F.Y.S. and Ö.Y.K.; project administration, F.Y.S. and Ö.Y.K.; funding acquisition, F.Y.S. and Ö.Y.K. Both authors have read and agreed to the published version of the manuscript. Funding: This research received no external funding. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: The data presented in this study are available on request from the corresponding author. Conﬂicts of Interest: The authors declare no conﬂict of interest.

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