Arena tip salonlarda mimari tasarım öğelerinin bilgisayar simülasyon çalışması ile akustik açıdan irdelenmesi
The examination of architectural design elemnts in arena type of halls with computer simulation
Yazar: DİLARA TEKE
Danışman: PROF. SEVTAP YILMAZ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Mimarlık Ana Bilim Dalı / Çevre Kontrolü ve Yapı Teknoloji Bilim Dalı
Derece: Yüksek Lisans, 2012
Konu: Mimarlık = Architecture
Dizin: Akustik = Acoustic

Özet:
Yıllar boyunca salonlarda akustik, dikdörtgen tipli salon şemalarında ve kaynak olarak klasik müzik kullanılarak incelenmiştir. Fakat günümüzde farklı müzik türleri için de uygun akustik ortamın sağlandığı salonlar inşa edilmektedir. İnşa edilen bu salonlar farklı plan şemalarından oluşabilmektedir. Bu şemaların ana karakterleri sahne yerleşimine ve izleyicilerin konumlanışına göre değişmektedir. Sahnenin kenarda olduğu klasik plan şeması, en uygun müzik koşulu gibi gözükse de, seyircinin sahneye uzaklığının artması gibi bazı sorunlara neden olmaktadır. Ayrıca sahne kabuğunun ayrı olması müzisyen ile seyircinin bulunduğu akustik çevreyi farklılaştırmaktadır. Salon içerisinde yansımaların homojen olarak dağılması gerekmektedir. Sahnenin ortada olduğu arena tipli salonlarda ise seyirci ile sahne etkileşiminin artmasına rağmen, sahnenin ve dolayısıyla müzisyenlerin yeterli yansıma alamaması gibi sorunlar açığa çıkmaktadır. İlk bölümde salon tasarımı için uyulması gereken tasarım kriterlerine değinilmiştir.Çalışmanın ikinci bölümünde salon değerlendirmesi yapılırken genel olarak kullanılan nesnel ve öznel değerler tanımlanmıştır. Aynı zamanda en önemli parametre olan müzik eylemi ve enstrümanların frekans değerleri ile ilgili bilgiler verilmiştir. Bu bilgilere göre klasik müzik dışındaki pop, caz gibi diğer müzik türlerine uygun akustik çevrenin tasarımı da tartışılmıştır.Çalışmanın üçüncü bölümünde, tasarlanan bir salonun özellikleri ODEON simülasyon yöntemi ile değerlendirilmiş, nesnel ve öznel değerler açısından irdelenmiştir. Üzerinde çalışılan ana salon şemasının plan, kesit şeması, malzeme kabulleri ve malzeme uygulama detayları bu bölümde verilmiştir. Kabuller ikinci bölümde belirtilen tasarım kriterlerine göre yapılmıştır. Simülasyonda kullanılacak olan alıcı ve kaynak noktalarının konumları, özellikleri bu bölümde yer almaktadır.Çalışmanın dördüncü bölümünde ise tavan, duvar, yansıtıcı panel gibi fiziksel tasarım parametreleri kontrollü olarak değiştirilerek farklar bulunmaya çalışılmıştır. Karşılaştırmalar çınlama, erken yansıma, geç yansıma, noktasal dağılım, bütünlük gibi değerlendirmelerin yapıldığı nesnel parametreler üzerinden yapılmıştır. Karşılaştırmalar seyirciler açısından yapılmakla beraber sahnede konumlandırılan ayrı bir alıcı ile performansçılar açısından da yapılmıştır. Alıcı noktaları bazında incelenen salon aynı zamanda parter bazında da irdelenmiştir.Son bölümde ise değerlendirmeler akustikçilerce ve ISO standartlarınca önerilen değerler ile karşılaştırılarak fiziksel tasarım kriterleri ile ilgili sonuçlar elde edilmiştir.

Abstract:
Over the years, the acoustic of halls has analyzed in rectangular shape halls with classical music as a source. However, today, different type of halls can be built, which provide proper conditions not only for classical music, but also for popular music such as jazz, pop, Latin music. These different types vary according to stage and audience situation. The plan scheme, which the stage is located in the side, seems to be the best type for halls, but with the enlargement of hall, the audience starts to become wider to the stage. Also when the stage has another ceiling and rear walls, it has different acoustic conditions from the audience hall. This conditions seperate the musician from the hall. When the stage is in the middle, the warmth and spaciousness increase due to the close connection between source and receiver. Also musician and audience share the same acoustic conditions. However, when the stage is in the middle, the lack of walls near the stage and audience, which provide beneficial reflections, cause weak situation for the stage and audience. In the first section, the general purpose and the method of the study have explained.In the second section, the acoustical parameters and the instruments? frequency spectrums have explained. There are subjective and objective acoustic parameters. The reverberation time, early decay time, sound strength, clarity, eraly lateral, late lateral sound strength and support are main musical parameteres. Early reflections mostly creates appereant sound with which effects the first impression and spaciousness. Late reclections are mostly important for the envelopement. Every instrument have different rising and decreasing sound curves. There are some criteria to design a halll such as material combination, room shape, room volume. To make the material design, it is important to have the suitible reverberation time according to type of performance, hall volume. After deciding the reverberation time, the bass and treble ratio of the hall should be decided. Material combination efects the low frequency and high frequency distribution in the hall. When the low frequency distribution is too much the music in hall sounds without brightness. On the other side when the high frequency distribution is too muchs, the hall will loose its warmth. In every type of music, it has own tempo, frequency spectrum and instrument combination. The hall is also discussed which type of music can be performed in. There are three main musical genre which are classical music, jazz music, popular music (pop, rock etc). The classical music and jazz music have close instrumentation but different tempo and melody. But rock music is very different from classical with its low frequency instruments such as drum.The ideal acoutic design is distrubute the low frequency much. But the rock music has too much low frequency which dıstrubs the audience in a hall suitable for classical music. The hall which rock music is performed in should be absorbtive in low frequencies.xxiiIn the third section the information of hall, which designed for the study, has given. The plan and section scheme of the hall designed according to acoustical design criteria. The sight lines, audience number, reflection surfaces are important to evaluate the plan scheme. The material decisions are given according to hall volume, reverberation time and the bass ? treble ratio. Because the stage locates in the middle, the stage walls should have maximum reflection as the side walls in the hall. The back side of the hall should be more absorbing to control the sound. To analyse the audience situation the receiver points are placed in every audience platform in the hall. The reciever - source positions and properties are given in this section. The source provides white sound which gives equal sound power in every one - third oktav frequency band. Receivers are omni receiver which collects reflections from every direction.In the fourth section, the physical design parameters have changed in computer based simulation program ODEON Combined 10.0, to make a compare in order to have the numerical information about effects of these parameters. To analyze the effect of ceiling form, the plan scheme, material choices stayed constant and different type of ceiling forms are evaluated in the simulation.The ceiling forms veried from straight to convex and to concave form. Mostly in arena type of halls the suspended ceiling reflectors are used in order to increase the beneficial reflections to the stage. But the shape, dimension and the height of the reflector effects the quality of the stage acoustics. In the second comparison different type of reflectors with different dimensions are simulated. The dimesions of the reflector should be enough to contrubute the distribution of reflections especially to the back side of the hall. The dimension of the reflector also should be enough big to reflect the low frequency reflections. When the hight of the reflector lower than the optimum height, the sound is stuck between the stage and the reflector which causes lack of reflection in the back side of the hall. In this chapter the sound rays are showed distributing from the source until it is absorbed by the hall. The simulations are analysed for both audience and the performer. The side walls are another acoustical design parameter which provides envelopement and spaciousness. Due to the location of the stage, the platforms are located as wineyard to provide reflection to the stage and front platform. So that the side walls form and hight are important for the acoustical surronding. When the surface is convex it becomes more diffuser, which makes the sound distribution more homogen. In the third comparison the side walls between the stage and the platforms are designed in two different forms which are straight and convex. The height of the side walls are also important for lateral reflections. As the height of the side walls increase the acoustical quality of the front platforms increase. On the other hand due to the increased height of the side wall, the back platforms got further from the stage which causes bad acoustical surrounding. Also the hall is simulated with a symphony orchestra which has 80 musical instruments such as violin group, chello group, brass group, string group, wood wind, percusion group.In the fifth section, the evaluation of receiver values and the average values in different type of halls have compared with the optimum values. The objective parameters such as reverberation time, early decay time, early lateral reflections, late lateral reflections, support, ensemble, sound strength are copmpared in each type of halls. When the ceiling forms are discussed the most effective ceiling form is the convex form which has optimum height. If the convex celing form is too low, it prevents the reflections to reach the back side of the hall. To improve the reflectionsxxiiicoming to stage the reflectors are analyzed and the optimum reflector is the seperate one which improves the reflections and doesn?t prevent the reflections reach the back side of the hall. Especially reflections coming from side wall are important to create envelopement for the audience. So that the convex form of the side walls are more effective then the straight side walls. The convex form let the reflections reach the back side of the hall. The convex form of the walls provides diffusion in order to have homogen sound distribution. The increasing the height of the side walls increase the early and late lateral reflections for the lower platforms but decreases the early - late lateral reflections and sound stength. When the orchestra has used in the simulation, the hall parameters provide the optimum values.The study has foucsed on the design effects on acoustical surrounding. Both the audience and performers are effected from these design decisions. Arena type of halls can have difficulties on having reflection especially for the stage conditions. On the other hand, it provides strong connections between stage and the audience. Differenet form of architectural design elements of the hall have compared with each other and with the optimum objective parameters such as reverberation time (RT), early decay time (EDT), early lateral reflections (LF80), sound strength (G), Late lateral sound strength (LG80), time center (TS) and support for the stage conditions. These subjective parameters calculates reflections and direct sound coming from the source and give results in every frequency band.