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Article Excerpt
Abstract: The influence of the interior surface materials on the acoustic performance of spaces is well known, both theoretically and practically. This paper gives a concrete example of this reality and summarizes the results of a detailed case study. The detailed measurements, calculations and evaluations were carried out on the auditorium of Yildiz Technical University, Istanbul, Turkey. As part of a renovation project, acoustic measurements were performed in the hall before the renovation, on the unfurnished hall and after renovation. The results obtained from these three distinct situations were evaluated in order to show the impact of interior surface materials on the acoustic characteristics of the space. In addition, the theoretically calculated acoustic environment was compared with the actual results after the renovation to evaluate the accuracy of the theoretical calculations.
Keywords: Acoustic performance, Auditorium, Interior surface materials
Introduction
The acoustic performance of a space is greatly influenced by the sound absorption capacity of the space itself. Thus, determining the sound absorption coefficients of the materials used on the interior surface of a space and the surface areas of these materials are considered to be among the critical design criteria. It should be borne in mind that, when the interior decoration or the surface furnishings of a room areas change, the acoustics of that room may also change. However, these parameters and the extent of the changes can only be determined properly by evaluating the real situation. Several studies have been published on this topic (Fausti, Farina, & Pompoli, 1995; Larsen, Olmos & Cade, 2004; Su & Yilmazer, 2006). One of the most comprehensive of these studies was carried out by Hodgson (2004) on university classrooms. In that study, detailed investigations were undertaken on 14 classrooms at the University of British Columbia, Vancouver, Canada, in order to compare the acoustic conditions before and after renovation. In another study conducted by Diaz and Pedrero (2005), the differences between the reverberation times (RTs) of unfurnished and furnished living rooms and bedrooms of dwellings were considered. In our study, unlike the previous studies, we aimed to compare the acoustic properties of an auditorium before and after renovation and also in the unfurnished condition during the renovation, by taking not some, but most of the significant acoustic parameters (Background Sound Level (BSL), Reverberation Time (RT), Early Decay Time (EDT), Definition (D50), Speech Transmission Index (STI) and Total Sound Level (TSL) into consideration. The auditorium of Yildiz Technical University (YTU) was examined. It was modified, in terms of both architectural design and interior surface materials, during a renovation project. The capacity of the hall was also increased by approximately 25% in order to accommodate a larger audience.
The study of the influence of the interior surface materials on the acoustic performance of the space included calculations and measurements. RTs, calculated in accordance with the Eyring method (Maekawa, 1994), were used to determine which surface materials would give the optimum acoustic performance and their surface areas. In order to predict the speech intelligibility and sound level in the hall, some calculations and evaluations were also made. Measurements of the hall's acoustic parameters (BSL, RT, EDT, D50, STI and TSL) were performed on the unfurnished and furnished (before and after renovation) auditorium. The distribution of the acoustic conditions throughout the space and the effects of the renovation on this distribution were determined by performing measurements at several audience locations in the hall.
Architectural Properties of the YTU Auditorium and the Selection of Interior Surface Materials
The auditorium, located in the central campus of the YTU, is mainly used for congresses, symposium, conferences and various other ceremonies. From time to time, it also hosts events such as concerts.
The hall was renovated in order to increase the audience capacity and eliminate some of its disadvantages, while preserving its general architectural characteristics. First, two additional spaces were constructed adjacent to the two opposite edges of the building, one of which was designed as a foyer, and the other as a service office. The new spaces were designed to include entrances to the main hall. This design solution eliminated the negative situation of the entrances and exits being very near to the stage (Figure 1). The absence of a professional translation system, which had been considered to be a significant drawback of the hall, was also been eliminated by establishing the required space and system. Unfortunately, due to the lack of space, part...
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