Examinando por Materia "Fuentes de sonido"
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- PublicaciónAcceso abiertoAuralización interactiva de barreras acústicas utilizando el método de acústica geométrica y elementos finitos(2019) Silva Carmona, Sergio; Moreno Gil, Andrés Felipe; Murillo Gómez, Diego MauricioThe present work aims to develop an interactive auralization system comprising the entire frequency range of human hearing. The objective is to auralize the screening effect produced by an acoustic barrier (AB). This objective was accomplished with the integration of two methods used to model the propagation of sound: Geometrical Acoustics (GA) and Finite Element (FE). This system allows users to move and rotate in a virtual environment perceiving the pressure variations of the sound field according to its spatial location. The inclusion of the FE method for the numerical solution of the wave equation is a consequence of the limitation of the GA method at low frequencies. In the addition, the use of this tool allows the calculation of the transmission loss (TL) of the acoustic barrier, as well as the estimation of the diffraction phenomenon. Based on the above arguments, a free-field domain was designed for both methods, with the assumption of anechoic boundary conditions. The following step was the synthesis of B-format signals that contain the spatial information of the domain. In GA, the creation of B-Format signals is done by the export of Wav files generated by the software. In the case of FE, it is done through the formulation of an inverse problem, that using discrete pressure data allows the determination of the synthesis of the complex spherical harmonic coefficients. After obtaining the B-Format signals in both GA and FE, a crossover to integrate the impulse responses (IR) obtained by both methods is designed. Additionally, an algorithm developed in Max and articulated with Unity software is created in order to generate a visual interface that allows the real-time spacialization of the effect of a AB based on the position and orientation of an avatar within a virtual environment. Finally, the result is the rendering of the sound pressure considering the effect of an AB by means of the two above mentioned methods. Consequently, a computational tool to auralize the screening effect generated of a AB in real-time is provided.
- PublicaciónAcceso abiertoCaso de estudio para la comparación de dos arreglos usando el sistema RCF HDL 20a, simulados mediante el software EASE FOCUS y las mediciones de presión sonora y direccionalidad aproximada capturadas en su implementación real(2016) Laino Guerra, Luis Felipe; Présiga Ríos, Sebastián; Buitrago Montañez, David ManuelKnowing the need that exists for sound engineers alive to deliver solutions to optimize time and resources when designing a system sound reinforcement, different tools that allow the possibility of estimating the behavior of a system in specific situations are used. A tool for this are prediction software and simulation, which are based on system behavior in a free, infinite and ideal field, omitting steps and calculations of great importance that can affect spreading response of each particular arrangement, so this work contains a case study to compare the results of simulations of sound pressure levels and approximate directionality of two arrays of speakers from RCF HCL 20 a system is performed, using the Ease Focus software against measurements specify the same parameters and the same system for real conditions. Grupo de Investigación: Modelamiento y Simulación Computacional. -- Línea de Investigación: Acústica y Procesamiento de Señales. -- Área: diseño de sistemas de sonido. -- Tema: diseño de sistemas de sonido.
- PublicaciónAcceso abiertoClasificación de escenas acústicas a través de descriptores de audio y máquinas de aprendizaje. Aplicación en escenas de Medellín(2019) Chica Osorio, Carlos Andrés; Yurgaky Valoyes, Dudley; Ochoa Villegas, JonathanIn recent years, automatic learning methods have been paired to obtain models for the analysis and classification of audio signals, such as the support vector machines, Ensemble Classifier, among others. These methods present a problem because they are not very understandable in their internal functioning, since they do not show the user an explanatory structure of how predictions are made and that they are understandable. It is worth mentioning that the models are accurate, but they are not presented properly. There is not a sound bank of the acoustic scenes of the city, it was necessary to record these outside scenes in the field. Audio descriptors such as MFCC and Chroma Vector were used to identify the acoustic scenes together with two SVM algorithms and one Ensemble Classifier. The result was an efficiency rate of 72.22% for the cases of SVM machines (Medium Gaussian and Quadratic), which are satisfactory. On the other hand, the learning machine based on Ensemble Classifier (Boosted Tree) had an Accuracy rate of 55.55%, this being a low performance machine.
- PublicaciónAcceso abiertoDesarrollo de un algoritmo de procesamiento de señales con arreglos de hidrófonos para la ubicación de fuentes subacuáticas(2017) Builes Suárez, Sebastián; Franco Bedoya, Ramiro EstebanSource location is an important aspect in defense and monitoring in different knowledge areas, in response to the need of developing a tool able to execute this task, the present work proposes the implementation of direction of arrival (DOA) algorithm designed for underwater aplications under the research project of acoustic detection of targets, focusing in advanced methods of beamforming. The algorithms were implemented and validated by the numerical method of pseudo-spectral k-space, Ąnding a high coherency in their responses compared with the theoretical far-Ąeld model. In the design stage three kind of arrays are proposed and tested in controled conditions with no satisfactory results, Ąnding failures and performing an analysis of the methods and arrays by means of array signal processing theory tools
- PublicaciónAcceso abiertoEstrategias para la adquisición de información asociada a tráfico vehicular y su aplicación en mapas de ruido(2019) Duque Gutiérrez, Carolina; Murillo Gómez, Diego Mauricio; Ladino Velásquez, AndersonThis project addresses the acquisition of non-authoritative collaborative traffic flow data to predict the noise generated by urban roads, in order to do noise maps. For this, traffic information is acquired using collaborative platforms such as Google Maps, which gives the information of travel time and speed in a length path. To determine the traffic flow, it has been done a correlation of the amount of vehicles that travel with a specific speed in a certain type of road. For this, it was necessary to characterize the roads in the city of Medellń and to study its typical behavior with help of data taken in field by studentes of the Universidad de San Buenaventura and information given by the Secretaría de Movilidad of Medellín, and data taken from Google Maps. One of the methodologies proposed was to find the correlation by filling an area with the amount of vehicles that typically travels a specific road then according to the speed determinate the amount that circulate in certain time, taking into account the space between vehicles called Gap. Besides, it was studied the sensibility of the obtained data in terms of the noise emission doing some simulations with it. The proposed methodology has been tested in two areas of the city. The results indicate that it is possible to use Google Maps information to predict urban noise although further analysis are required to improve the estimation of traffic flow based on the type of road, speed and time travel
- PublicaciónAcceso abiertoLocalización de fuentes sonoras mediante reconocimiento de del vector de intensidad acústica y la técnica de Beamforming haciendo uso de la Sonda P-U(2016) Araque Argüelles, César Augusto; Acosta Agudelo, Oscar EsneiderIn this document are presented how, by the use of the Microflown Technologies’s P-U probe, is obtained the localization of a sound source. This source localization is tackled by two techniques: by the recognition of the acoustic intensity vector and using the beamforming technique. Also, this document presents the methods to carry out the measurements, the restrictions of the source characteristics, the limitations of both techniques and the actual used procedures. The localization is plied to two different sound sources, an electroacoustic source radiating a controlled signal and a non-electric-acoustic source (a blender motor). For both sources it is wanted to obtain its localization in two different places: A closed space, with low levels of background noise and controlled absorption, and an open space. From the results it’s made comparison between the found localization for different frequencies, between the evaluated sources and between the chosen places.