Jorge Francés Monllor

Influence of material properties on sound radiation for flat loudspeakers

This work aims to analyze numerically, analytically and experimentally, the influence on sound power radiated, frequency response, and directionality of different materials in flat loudspeakers. Concerned experimental setup, the excitation force consists in a shaker which his mechanical characteristics are completely known. Finite Element Method has been used to simulate this configuration .The analytical model used couples the electrical, mechanical and acoustical system of the panel. The parameters of the panel material which we are focused are elastic modulus and loss factor. The analytical formalism serves as the basis to study the structural and vibrational behaviour of the system that also is analyzed with experimental results. The results obtained from different materials and different excitation position serves as basis for optimum configuration in this type of speakers.

Psychoacoustic evaluation of compression drives

The following work tries to be an approximation to the sound quality valuation of radiant systems, in concrete, the case of compression drives. This approach is realized from different perspectives: on one hand, an evaluation of the quality of these systems from the point of view of the psychoacoustic classic parameters described by Zwicker will be done. On the other hand, a perceptual model described by Moore and based on the human auditory system will be applied. Both models will be applied in signals registered on different commercial models of compression drives. The work also includes the accomplishment of a psychoacoustic experiment in which a hearing will realize a valuation of perceived quality. Finally, one will try to establish a correlation with the information obtained in the three mentioned approaches.

Characterization of laminated glasses by means of an inversion method using Finite Elements

The experimental determination of elastic modules and loss factor in laminated glass components is of great interest in building acoustics since at present there are a lot of building systems using these types of devices. This makes it necessary to predict the transmission losses in a partition. Even though described in regulation, the process is not exempt from serious difficulties. In this work we present a method in order to obtain the parameters mentioned above for a laminated glass composed of a sequence of isotropic layers by solving the model‐based inverse problem for frequency admittance experimentally obtained. The parameter that best describes the mechanical constants of material of the layers is obtained by minimizing the discrepancy between the real numerically and numerically predicted waveform. This is done using an iterative optimization. A sensitivity study of the parameters uncertainty is performed in order to establish the feasibility of this technique.