Building Acoustics

240 Building acoustics measured and calculated results compares very well. The standard EN 12354–2 gives an alternative expressi ...

Sound transmission 241 6.5.1 Sound transmitted through an infinitely large plate We shall assume that the plate lies in the xz-p ...

242 Building acoustics Having characterized the plate by its mass impedance, also having no internal energy losses, the transmis ...

Sound transmission 243 () 44 B j()ˆ ˆ()x x. x pk uk Bk k ω = − (6.86) We observe again, as when discussing the radiation factor ...

244 Building acoustics The equation clearly shows the presumption for the derivation in the preceding section; the wall impedanc ...

Sound transmission 245 2 2 w w 0 0 11 cos , 10lg 10lg 1. cos 2 1 2 Z R Z Z Z φ τ φ τ ⎡ ⎤ ==⋅=⋅⎢ +⎥ + ⎢ ⎥ ⎣ ⎦ (6.98) The wall imp ...

246 Building acoustics calculatation assuming an ideal diffuse incident sound field; i.e. assuming sound incidence evenly distri ...

Sound transmission 247 Being pragmatic, we could investigate the applicability of the infinite plate model to real situations an ...

248 Building acoustics 6.5.2.1 Formulas for calculation. Examples One should not be surprised, taken the complexity of the task ...

Sound transmission 249 A major problem performing these comparisons is the availability of a complete set of specifications for ...

250 Building acoustics An example of the latter effect is given in Figure 6.24, which shows measurement data and calculated resu ...

Sound transmission 251 addition we have also plotted the resonant part separately. As evident from the figure, the resonant part ...

252 Building acoustics in industrial buildings are plates where the corrugations have a trapezoidal shape, commonly called cladd ...

Sound transmission 253 (^) () 2 22 4 w c1 c2 j1 cos sin 1jsin. ff Zm ff ω θθηφ ⎡⎤⎛⎞ =⎢−⎜⎟+ + ⎥ ⎢⎥⎣⎦⎝⎠ (6.108) The expression, ho ...

254 Building acoustics fixed the upper limit at 0.96, which corresponds to a maximum angle of incidence of approximately 78°. Th ...

Sound transmission 255 respectively. The measured results in Figure 6.28 are reproduced from Hansen’s data but the calculated re ...

256 Building acoustics 6.5.4 Transmission through porous materials As pointed out in the introduction to this chapter, high soun ...

Sound transmission 257 Apart from the very low frequency range we get a very good fit between measured and calculated results. T ...

258 Building acoustics 6.6.1 Vibroacoustic reciprocity, background and applications Generally, presenting the reciprocity theore ...

Sound transmission 259 2200 00 44 , cc pWaF A A ρρ  =⋅=⋅ (6.115) where A is the total absorption area of the room. We further ...