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Software for simulation of acoustic pressure distribution
Hampl, Filip ; Schimmel, Jiří (referee) ; Kurc, David (advisor)
This semestral thesis deals with the creation of software to simulate the distribution of sound pressure. Basic principles of sound propagation are explained which are necessary for an understanding of the issue. There is a description of the velocity potential and its application in creating simulations. Another issue is the introduction of wavefield synthesis, which is essentially a technology for simulation of primary sources with secondary sources. Advantages of wavefiled synthesis are discussed as well as disadvantageous aspects. The practical part of this work is creating a user interface in Matlab, which allows user to plot the distribution of sound pressure of one or interaction of more emitters. Another possible outcome is to display the directional characteristics of real resources. At the very end of the work the direction of further work is outlined.
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Objective Criteria for Room Acoustics Assessment
Zwins, Jiří ; Kurc, David (referee) ; Schimmel, Jiří (advisor)
The aim of this thesis is to define basic concepts of acoustics, a closer acquaintance with the defined objective criteria for evaluation of acoustic spaces and practical processing algorithms in Matlab. The central part is presented technique of calculating the reverberation time by integrating the measured room impulse response and its graphical output. The reverberation time is just one of objective assessment criteria acoustic spaces. The calculation algorithm is based on the principle of a closed space Dirac excitation pulse and the subsequent decline in energy determination of the reverberation time of the acoustic pressure. The analysis of the data samples were used specified areas in VUT Brno.
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Loudness Index Measuring
Hloušek, Pavel ; Mach, Václav (referee) ; Kurc, David (advisor)
This thesis deals with noise measuring. There are described methods of measurement and evaluation of noise, focusing on Steven’s loudness calculation method. Basic concepts of acoustics are provided in the first part. There are also mentions measurement of noise using microphones and sound level meter. The second part is focused on the practical solution of thesis. In which it is made measurement of noise using sound level meter NTi Acoustilizer and implementation of the graphical user interface for calculation of the Steven’s loudness index in Matlab.
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Acoustic Signal Recording and Processing Using B-Format Technology
Kurc, David ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This bachelor’s thesis is focused on the system of recording and processing of acoustics signals called Ambisonics. It describes single sections of this system in the chain of acoustic signal processing. At most it is aimed at the B-format technology as the main ambisonic instrument, its encoding from the signals recorded with the special microphone capsule of the soundfield type or with help of encoding equations and its decoding into single speaker channels of various speaker arrays. The UHJ transmission format is also mentioned. The application B-format Decoder was created in the MATLAB programming environment. It consists of several functions and has friendly user interface, which provides the processing and decoding of B-format components for the speaker array with entered parameters. Among others this interface ensures loading, displaying, analysis and playback of source and resulting acoustic signals.
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Design of Reverberator for Room Acoustics Simulation
Húserka, Jozef ; Orlovský, Kristián (referee) ; Kurc, David (advisor)
This thesis deals with artificial simulation of acoustic spaces by using reverberators. Output of this document consists of four reverberation algorithms and function that evaluates objective parameters of acoustic space from impulse responses. Reverberators and script were implemented using Matlab. Graphical user interface is used to present all of the algorithms for easier usability. First chapter deals with objective parameters of acoustic spaces and the ways they are computed from impulse response. Second chapter describes various structures which are used to build reverberators. Those structures are used in third chapter in implementations of reverberators. Third chapter also compares all implemented reverberators . In last chapter experiment was made. Impulse responses of three spaces were measured and subsequently aproximated by algorithms implemented in this thesis.
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Simulation of sound wave propagation in closed space
Černý, Filip ; Kurc, David (referee) ; Orlovský, Kristián (advisor)
This thesis is dealing with problem and solution of simulation in room acoustics. At the beginning is introduction with sound as waves and his behavior in closed space. Following part of text is dealing with computional methods in room acoustics, statistics methods , ray-based methods, wave-based methods. Following are focused FDTD wave method, which serves as the basis for creating simulation algorithm.Last part of this work is practical sample of MATLAB aplication enviroment for simulation of sound waves in closed room by explicit sub-methods of method FDTD. The last section contains an example and discussion of the results of simulations.
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Using reverberators to modify space acoustics
Pavlikovský, Vladislav ; Orlovský, Kristián (referee) ; Kurc, David (advisor)
This diploma thesis deals with adjusting the reverberation time of enclosed spaces. It is divided into two thematic areas. The first thematic area deals with active systems that adjust the reverberation time, with a stronger focus on usage of reverberators to simulate secondary spaces. The second thematic area is the implementation of reverberators and their fundamental building blocks in Matlab.
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Simulation of sound source motion for multichannel speaker topology
Dvořák, Petr ; Kurc, David (referee) ; Orlovský, Kristián (advisor)
This paper describes the simulation of the motion of a sound source in space with several speakers. It deals mainly with the study and subsequent implementation of events necessary for simulating the motion of the virtual sound source. The theoretical part is therefore concerned with finding these phenomena and with their description. Mainly that means description of panning of the sound and of the Doppler effect. In the following practical part of the work, the previously described phenomena are applied into Matlab. In the created interface , it is then possible to select the parameters of the simulation, such as the trajectory of the motion of the virtual sound source, the number of the points of the trajectory, etc. Analyses of the generated signal are then made of the selected referential parameters of the simulation.
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Noise Source Identification Using Beamforming
Kurc, David ; Míča, Ivan (referee) ; Schimmel, Jiří (advisor)
This master's thesis is focused on the noise source identification using microphone arrays and beamforming as the signal processing method. It describes parts of such a system and provides a comparison with other systems that serve a similar purpose (eg. NAH). Various types of microphone arrays are mentioned with their influence on the resulting ability to identify the noise source. We are further focusing on Delay-And-Sum technology, on which we are explaining the basic principles and constraints of beamforming. The practical part describes the implementation of the DAS method in MATLAB and C language, the specific structures of built microphone arrays and assembly of complete systems capable of identifying sources of noise. These systems were tested by performing a practical experiment. Achievements in the form of distribution maps of acoustic energy in the focused space are interpreted in the last chapter.
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