Assessment of a hybrid numerical approach to estimate sound wave propagation in an enclosure and application of auralizations to evaluate acoustical conditions of a classroom to establish the impact of acoustic variables on cognitive processes

摘要

In this research, the concept of auralization is explored taking into account a hybrid numerical approach to establish good options for calculating sound wave propagation and the application of virtual sound environments to evaluate acoustical conditions of a classroom, in order to determine the impact of acoustic variables on cognitive processes. The hybrid approach considers the combination of well-established Geometrical Acoustic (GA) techniques and the Finite Element Method (FEM), contemplating for the latter the definition of a real valued impedance boundary condition related to absorption coefficients available in GA databases. The realised virtual sound environments are verified against real environment measurements by means of objective and subjective methods. The former is based on acoustic measurements according to international standards, in order to evaluate the numerical approaches used with established acoustic indicators to assess sound propagation in rooms. The latter comprises a subjective test comparing the virtual auralizations to the reference ones, which are obtained by means of binaural impulse response measurements. The first application of the auralizations contemplates an intelligibility and listening difficulty subjective test, considering different acoustic conditions of reverberation time and background noise levels. The second application studies the impact of acoustic variables on the cognitive processes of attention, memory and executive function, by means of psychological tests.