Building Acoustics

140 Building acoustics The width w is normally chosen in the range of 5–10 cm. Making the wells too narrow may increase the surf ...

Room acoustics 141 optics may be used. We shall not treat any of these methods here, but to illustrate the effect of these diffu ...

142 Building acoustics The sound scattering objects are assumed to be point like and the energy of the incident wave is scatter ...

Room acoustics 143 1 1 , 4 N i i S q V = = ∑ (4.71) when a total of N objects with surface areas Si are present in a room of vol ...

144 Building acoustics Most are developed for applications in performance rooms, i.e. for predicting the acoustics in rooms for ...

Room acoustics 145 The total energy density at a receiving point at a given distance r from the source is assumed to be given by ...

146 Building acoustics absorption characterized by the power attenuation coefficient m. All these attenuation processes may be a ...

Room acoustics 147 (^) d0() 0 Fe 2 w WK r qmr rc h h α π =⋅ ⋅⎛⎞′ −+ ⎜⎟ ⎝⎠ . (4.80) Figure 4.22 The relative sound pressure level ...

148 Building acoustics Floor: α = 0.05 Scat. elements: α =0.01 q = 0.025 1.0 23 5 10.0 2030 50100.0 Distance (m) -60.0 -50.0 -40 ...

Room acoustics 149 4.8.1.4 Reverberation time Another effect to be observed in large rooms containing a large quantity of scatte ...

150 Building acoustics In more recent time, the practical use of such analytical models is certainly reduced due to powerful com ...

Room acoustics 151 4.9 References ISO 9613–1: 1993, Acoustics – Attenuation of sound during propagation outdoors. Part 1: Calcul ...

152 Building acoustics Krokstad, A., Strøm, S. and Sørsdal, S. (1968) Calculating the acoustical room response by the use of a r ...

Room acoustics 153 Vorländer, M. (1995) Revised relation between the sound power and the average sound pressure level in rooms a ...

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CHAPTER 5 Sound absorbers 5.1 INTRODUCTION In the preceding chapter on room acoustics, we presupposed that an absorption factor ...

156 Building acoustics A number of other methods, most of them non-standard, are also in use both in laboratories and in the fie ...

Sound absorbers 157 Plastic fibres products, e.g. polyester fibres materials, are also becoming popular for sound absorption. Th ...

158 Building acoustics component, which traditionally has been accomplished by filling the cavity behind the plate partly or who ...

Sound absorbers 159 independent of the size of the specimen, which is normally quite small. The homogeneity of the material is t ...