Evaluación de la influencia de complementos en la respuesta biaural y su aplicación a la acústica virtual

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La acústica biaural representa aquella parte de la acústica que se centra en el estudio del sonido enfocado a la escucha del ser humano. Por esta razón, los sistemas basados en Realidad Virtual, o derivados, pueden alcanzar una relación de simbiosis con la acústica biaural. Actualmente, el audio presente en sistemas de Realidad Virtual no tiene en cuenta, de forma habitual, los efectos acústicos relacionados con la presencia de objetos en el entorno cercano del receptor. El presente trabajo evalúa la influencia del uso de complementos textiles, u otro tipo de objetos en los sistemas basados en acústica biaural, estudiando los efectos de la presencia de dichos complementos, los cuales modifican las características acústicas del sistema. Los resultados obtenidos evidencian que la presencia de objetos en el campo próximo al individuo causan una serie de modificaciones significativas en la acústica biaural del mismo, cuya relevancia depende directamente del complemento utilizado. De hecho, para algunos tipos de complemento, la magnitud de la influencia que causan sobre la recepción del sonido es tan importante, que resultaría preciso tenerlo en cuenta en el diseño de un sistema de acústica virtual que lo incluya.
Virtual Reality can be defined as the representation of a non-existent environment in which a user can to interact and receive sensory feedback. In addition, binarual acoustics represents a part of acoustics that studies how acoustics waves are received by the human auditory system. As a consequence, these systems based on Virtual Reality, or derivatives, can achieve a good symbiosis relationship with binaural acoustics. For decades, applications and devices have been developed to achieve the primary goal of Virtual Reality: the immersion of the user in a virtual world. The consecution of this objective is mainly based on the integration of sensory stimuli, that try to recreate realistic situations in an environment alien, into reality. Among these stimuli, those related to the sense of sight and the sense of hearing stand out especially. In the paradigm of acoustics, one of the main factors that act on immersion is sound spatialization. In other words, the ability of a system to give the user the capacity to place sound sources in a virtual space. To deal with this, systems based on psychoacoustics have arisen, such as stereophony, quad systems or multichannel systems, and other more sophisticated systems, non-based on psychoacoustics, such as Ambisonics, Wave Field Synthesis or the biaural method, in which this work is grounded. Currently, audio used in Virtual Reality systems ussualy does not take into account the acoustic effects associated with the presence of objects in the immediate vicinity of the receiver. This results in a loss of quality in the user experience. The objective of this work is to evaluate binaural acoustics by modifying the physiognomy of the human being through the use of textile garments or other objects that modify the physiognomy of the individual. This goal was achieved by means of a study of the acoustic modifications observed from the point of view of binaural acoustics. In addition, an empirical analysis is carried out to quantify the influence of a series of complements on the individual’s listening. Lastly, a system based on equalization is proposed, to make the user’s experience of Virtual Reality applications more complete. The construction of a binaural system is executed through a process called auralization, which consists on the convolution of a sound stimulus obtained in anechoic conditions with the binaural impulsive response of a room. In order to carry out the auralization process, the three main components of the communication process must be taken into account: the sender, the medium and the receiver. Regarding the first component, the sender, a sound source needs to be described in terms of its acoustic power and directivity. These signals used in virtual reality systems must be recorded in anechoic conditions or synthesized without any added reverberation. In addition, the signal-to-noise ratio, binary regime and signal quantification must be high enough to avoid glitches or other unwanted effects...
Acústica, Acústica biaural, Realidad Virtual, Head-Related Transfer Function (HRTF), Proceso de señales, Signal processing, Control theory, Acoustics
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