Analýza šíření hluku se zvláštním zaměřením na nízkoúrovňová měření

Abstract

The present dissertation deals with the comparison of experimental, analytical and mathematical analysis of noise propagation in spaces with extremely low noise levels. All analyses are performed for special acoustic laboratories – anechoic and semi-echoic measurement rooms with known acoustic performance requirements and known design. The main objective is to verify the mathematical models to match the experimentally determined values and to be further used for other acoustic problems. A sub-objective is then the design of the acoustic performance mapping of these measurement rooms, especially in terms of the effectiveness of the applied vibration isolation of the installation, the sound insulation of the main building structures, the background noise values, the validity of the inverse square law and the length of the reverberation time. The second sub-objective is the construction of mathematical models of specific parts of the measuring room with sufficient predictive ability, especially for the vibration isolation of the measuring room installation, the measuring room building envelope in regard to its sound insulation, the analysis of the reference environment with regard to the absorption of the surrounding structures and the analysis of the reverberation time or absorption in the reference environment. In the introduction, the use of measuring rooms is generally summarised, the basic characteristics of the measuring rooms under investigation and the basic physical principles used for the design of these laboratories are described. The basic technical standards and publications that served as the main basis for defining the objectives and preparing the present work are described. A significant part of the thesis deals with the description of the methods used for the analytical determination and experimental mapping of the properties of the laboratories, as well as the methods used in the mathematical modelling of the individual structures. The final part of the thesis presents the specific procedures that led to the quantification of the required properties of the laboratories and the results of the individual sub-measurements followed by the results of the mathematical modelling. The results of the individual parts are then evaluated and compared with each other, and procedures for further potential use of the selected procedures and a description of follow-up research topics arising from this work are outlined.