Examinando por Materia "Tiempo de reverberación"
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- PublicaciónAcceso abiertoAnálisis de absorción en baja frecuencia que produce el uso de varias capas de material absorbente y diferente distribución mediante método analítico y medición con estándares tipo ISO(2020) Arias Arboleda, Susana; Ochoa Villegas, JonathanAbsorption coefficients represent the capacity of sound absorption acoustic materials. This parameter is estimated from measurements such as those specified in ISO type parameters. As for example, regulation 354 estimates the coefficient of absorption at random incidence through the measurement in reverberant chamber and regulation 10534 estimates the absorption at normal incidence using as a tool a tube of standing waves. Most manufacturers of absorbent materials have the estimated absorption coefficient between the frequencies of 125 Hz to 4000 Hz. The low frequency range is usually not reported since the absorption coefficient is not relevant, although it is also of interest in the implementation and therefore an evaluation is necessary. This project aims to find a methodology that allows, through international methods and analytical methods, to estimate the absorption coefficient at low frequency when the thickness of three absorbent materials increases, Frescasa (glass wool), Acustiplaca (pressed rock wool) and Acustifibra (pressed glass wool). The study focuses on the study of frequencies between 63 Hz to 250 Hz, in addition to this, the effect of estimating the absorption coefficient on different distributions is investigated. For this purpose, panels with several layers of absorbent material have been designed to be measured by ISO 354, placing the panels in two positions, vertical and horizontal. The absorption coefficient is estimated using several layers of absorbent material according to ISO 10534-1 in impedance tube. With the proposed methodology, the measurements in the impedance tube were analyzed according to layers of material to determine how to modify the absorption coefficient as the thickness increases. In a reverberant chamber, measurements can be made with the multilayer panels in a vertical position and in a horizontal position. As an analytical method, the Allard and Champoux absorption model is implemented by varying the thickness of the materials and taking into account the resistivity value for each material. With the results obtained, it was concluded that the thickness of the absorbent materials increases, which represents an increase in the absorption coefficient at low frequencies and is also a physical characteristic that predominates over density. However, it is necessary in future studies to define the feasibility of this method, in order to optimize the strategies that are required in each case of acoustic conditioning that link problems in low frequency.
- PublicaciónAcceso abiertoAnálisis del impacto de ruido de fondo y tiempo de reverberación en procesos cognitivos por medio de Auralizaciones(2017) Escobar Ochoa, Sara; Pérez Betancur, Diana Carolina; Ortega, AlexánderThe research below proposes a method to analyze the influence of reverberation time and background noise upon cognitive processes of attention, memory and executive function. To characterize the acoustic variable (reverberation time) acoustic models are implemented using the software CATT-Acoustic, making auralizations with the messages with four different reverberation time conditions, matching a characteristic enclosure of a learning area from the San Buenaventura University, to use along with the psychological tools. Background noise conditions from the room were measured with a binaural head [Cortex MK2b, 01dB], assessing four of this levels. The pilot test mode applied showed a negligible impact from the acoustic variable on cognitive processes, due to the amount of specimens and variations observed on the application protocol, i.e. examination mode, timekeeping of the test, compromising consequently the results. In a complementary test in which the amount of four specimen groups where increased it showed a positive influence of a high background noise in four components of the verbal memory plot curve, where the attention and memory processes are assessed, and a negative influence of a long reverberation time, in the verbal memory components as well as in the Wechsler memory scale.
- PublicaciónAcceso abiertoDeterminación del efecto causado en procesos cognitivos por el tiempo de reverberación y ruido de fondo mediante el uso de auralizaciones(2018) Restrepo Dávila, Felipe; Ochoa Villegas, JonathanIn this work, the experimental design was presented in the form of a replica, in which a sample of sixty university students was evaluated in order to determine the effect caused by reverberation time and background noise on the cognitive processes of memory, attention and executive functions, seeking to contrast the results obtained in previous researches. Statistical analysis is presented in order to relate the effect of these acoustic parameters. Five psychological instruments were applied where four of these psychological instruments were auralized taking into account the acoustic conditions measured and the hypothetical treatment of the mini auditorium 2 of the University of San Buenaventura, San Benito Medellín. For the application of the test, the recording room of studio A of the University of San Buenaventura Medellín was used and the psychological instruments were reproduced using the Opsodis binaural reproduction system as specified in the connection diagram of section VII.A and the distribution within the recording room as shown in Figure 8. It was found that the results found in previous theses where the impact of reverberation time and background noise on cognitive processes was evaluated are similar, corroborating in the same way the foreign investigations, where it is proven that background noise and reverberation time significantly affect attention, memory and executive functions, being reverberation time the most affected acoustic parameter. High background noise causes interference in the communication of verbal messages, causing the individual to remain in an unnecessarily high attention span, which can have negative health effects such as fatigue and stress. The long reverberation time in turn causes loss of speech intelligibility, i.e. verbal messages are partially understood or sometimes confused
- PublicaciónAcceso abiertoDiseño y Construcción de un Paquete de 3 Plug-Ins en Formato VST.(2010-06) Vásquez Perdomo, Andrés Felipe; Delgado, David
- PublicaciónAcceso abiertoEvaluación de la influencia de las condiciones acústicas de las aulas en tres ciudades del país en el rendimiento docente y estudiantil(2018) Rodríguez González, Mauricio; Ochoa Villegas, JonathanThis project seeks to evaluate the acoustic conditions of the classrooms located in three cities of the country (Medellin, Bogota and Cali) to determine the acoustic impact they have on the teaching-learning process, the health of the teachers and the student’s cognitive performance. The next job is part of the macro project " Identification of factors of environmental performance (acoustic, thermal and visual) determinants of the mental health of teachers and students of public schools of Bogota, Medellin and Cali: Line bases for the analysis of impact of the public politics according to the norm NTC 4595 " conducted by COLCIENCIAS. To execute this project measurements of background noise, time of reverberation and acoustic isolation were realized in the selected classrooms, and there were obtained results that do not fulfill with the regulations, which makes necessary the development of a process of management of noise to control the acoustic problems that they present in the classrooms of the different schools studied. Keywords: Cognitive process, Background noise, Reverberation time, Acoustic isolation, Acoustic conditioning.
- PublicaciónAcceso abiertoSoftware que calcula el Tiempo de Reverberación para Cualquier Indice de Absorción.(2010-10) Gómez Londoño, Eduardo José
- PublicaciónAcceso abiertoUbicación estratégica de material absorbente basado en el análisis modal de una sala(2019) Tapias Pinzón, Diego Alejandro; Berrío Bernal, Juan DavidThis grade work was carried out in order to test the hypothesis that the location of the absorbent material at the absolute sound pressure maxima of a room decreases the reverberation time in the octave band to which the mode frequency belongs. The results obtained in the reverberation time T_15 and T_20 of a room in the 125 Hz octave band are presented, in which, by means of a modal analysis, the location of the absorbent material was varied in order to obtain the maximum absorption of sound energy. For its implementation it was necessary to carry out a survey of a 3D model of the room and import it into a finite element simulation software, with which the absolute maximum and minimum sound pressure was determined. A simulation was then carried out in the CATT-Acoustics v9.1 software, in which two panel configurations were tested, one in which the absorbent material was placed at absolute maximum pressure and the other at minimum pressure. After the simulation, a measurement based on an experimental design was performed. The measurement involved 18 combinations of source location, microphones and absorber panel configuration, after which the responses to the impulse of each combination were found by means of the MATLAB software and the reverberation time for each measurement point was estimated consecutively by means of the plug-in aurora software Audacity 2.0.5. Finally, a statistical analysis was performed to determine the factors that were statistically significant in the measurement results.