The paper concerns the eigenanalysis of acoustic cavities with the use of radial basis functions (RBF). The Kansa collocation method was used for determination of the natural frequencies and eigenvectors of 1D, 2D and 3D acoustic elds. Due to validation analysis of the proposed method, in simple examples like 1D, 2D rectangle and 3D rectangular parallelepiped all calculated eigenferquency and eigenvectors were compared with exact (analytical) results. All results indicate that using of multiquadric radial basis functions provide a results with very high accuracy in comparison to analytical results. In the paper a new method for determining the shape parameter of the multiquadric radial basis functions is described.

In this paper, an automated measurement system was proposed that uses a probe hung below a remotely controlled balloon to measure parameters of the acoustic eld in the whole volume of a room. The study was conducted to estimate distortions that such system may cause in the acoustic eld at the measurement point. The most signicant source of the distortions will be the buoyancy element one large balloon or a number of smaller ones. This paper considers dierent spatial congurations of spherical balloons with regards to alterations they cause in the acoustic pressure levels measured below them. Interior of a room without and with a group of spherical balloons was modeled using the boundary element method. Using a larger number of smaller spheres instead of a single large one did not signicantly reduce the related distortions. However, using two spheres slightly decreased distortions when the distance between the balloons and the recording point was relatively small.

The article presents the model of sound insulation of single homo-geneous baffles based on the Statistical Method of Energy Analysis. The determined frequency characteristics of airborne sound insulation of the baffles obtained from the calculation model with the results of experimental tests were compared. Calculations using the Statistical Method of Energy Analysis and laboratory tests were performed for plates made of plexiglass and acrylic.

In the paper basic theoretical models of transmission loss calculation are described. Here only single homogeneous isotropic panels are analysed. Three impedance values of one rigid and two flexible body models of panel are described and analysed. As flexible models the thin plate (Kirchhoff-Love plate model) i thick (Mindlin – Reissner model) are analysed.

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