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Room acoustic modeling
Bernát, Michal ; Balík, Miroslav (referee) ; Míča, Ivan (advisor)
This Master's Thesis deals with geometric modeling methods and theirs implementation in Octave (Matlab), which is ideal for the practical realization. The first part of the thesis is focused on a very simplified image source method, which is able to calculate and render the 2D impulse response of rectangular rooms. The next part is aimed on~the same method, but extended by three-dimensional simulation of polyhedral prism-shaped rooms. There is both an explanation of theoretical and mathematical aspects and a~documentation of the implemented source code. Extended image source method is able to generate sound representation of impulse response characteristics, and use it for auralization, which is achieved by using convolution of both the input sound source and the calculated impulse response. At the end there are two practical examples for both methods with explanatory illustrations.
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Design of modern speaker body with usage of new technology
Kůst, Martin ; Prokop, Aleš (referee) ; Řehák, Kamil (advisor)
This diploma thesis deals with the analysis and design optimization of a speaker cabinet (enclosure) produced by the additive technology of 3D sand printing. The introductory part is devoted to the theory, both in the field of noise, vibration and the method of their calculations, as well as the theory of speakers and their systems. Numerical and experimental modal analysis is performed, which were compared to determine the mechanical properties of the new material, including material damping. This is followed by experimental and numerical harmonic analysis, with output in the form of a numerical model describing the behaviour of the structure during its excitation. The data are compared with a modal analysis of the internal acoustic space and the critical shapes and their frequencies are determined. At the end of the work, construction modifications are proposed to increase the rigidity of enclosures, the influence of which is evaluated on the created numerical models.
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The analysis of acoustic properties of innovative wood-based materials
Svojanovský, Jan ; Nop, Patrik (referee) ; Jirásek, Ondřej (advisor)
The content of this work is research of innovative wood-based materials in the acous-tic perspective. Basically, the goal is to determine the influence of the internal structure of the wood-based material on variables, which are sound speed, acoustic resistance, or acous-tic constant. In total were measured 15 samples, each one was made in a different way. Each sam-ple was weighted, and the length of its sides was measured. By using the ultra sonic timer, it was measured the time of the sound impulses, which go through the samples in all of their axes for the purpose of observation the influence the fibers on speed of sound in the materi-al. The next thing to do was to determine another magnitude, which describe acoustic of the material. All measurements were taken in room conditions (room humidity). Six of the sam-ples, which were randomly selected from those 15 samples, were measured once again after two weeks. In those two weeks were all the samples saved in air-conditioned place in which was the room humidity distinct lower. In the end all the samples were compared with each other and they were also com-pared with materials which are commonly used in production of musical instruments or acoustic components. Possible use in the music industry was assigned to each sample.
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Acoustic emissions of buildings
Smažinka, Josef ; Uher, Pavel (referee) ; Rubinová, Olga (advisor)
The diploma thesis deals with acoustics with the main focus on acoustic emissions of buildings. The first part of the thesis aims to familiarize the reader with the field of acoustics as a whole. They will learn the basic concepts, quantities and relations that exist in acoustics. In the second part I focus specifically on the sources of noise in buildings and their surroundings, how can excessive noise affect health, what standards must be met and how to prevent excessive noise. The last part is devoted to practical measurements in the field, which is focused on real sources of noise in the city of Brno. The aim of this measurement is to compare the noise generated by buildings with other noises in the urban environment.
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Acoustical analysis of mechanical watsches
Dohnal, Marek ; Balík, Miroslav (referee) ; Sigmund, Milan (advisor)
This thesis is focused on the analysis of the characteristics of mechanical watches on the basis of their sound. There are theoretically analysed usual mechanical defects and disorders of watches and compensation of those defects. Particular attention is given to disorders, that can be extracted from the recorded acoustic sound of watches. There are also solved most appropriate methods of recording with a respect to the minimisation of ambient acoustic interference. The main part of this work is experimental measurement on watches and evaluation of achieved acoustic data. For this purpose, an autonomously running software were developed.
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Civic amenities building
Tesař, Ondřej ; Svoboda, David (referee) ; Berková, Petra (advisor)
The aim of this Master´s project is the design of the elementary art school in Slavkov u Brna. The thesis is divided into three parts. The first part deals with architectural and structural design of the building, the second part with design of selected building services, and the third part with a noise study of the building. The building has two floors and a flat green roof. It is operationally divided into two sections with a common entrance - the art school itself and the concert hall. The first section consists of the office, six classrooms, a room for music theory, a choir room, a storage room, and sanitary facilities. The second section includes the concert hall, gallery, foyer, prep room, and sanitary facilities. The technical equipment of the building is located on the second floor. The building has load-bearing ceramic masonry walls, based on plain concrete foundation strips. The floor and roof structures are designed as cast-in-place reinforced concrete slabs. The partitions design is ceramic masonry units and acoustic plasterboard walls. The facade design combines greenery and ventilated cladding. The design building services include heating with two heat pumps, ventilation and cooling with two air ventilation systems, rainwater management for toilet flushing, artificial lighting, and photovoltaic power plants for the building services. The noise study covers issues of sound insulation of the building structures, reverberation time in selected rooms, and an urban acoustic study. The result is the correct design of the building in terms of acoustic comfort.
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Design and Realization of Modification of Acoustic Field in Laboratory
Ješko, Petr ; Rášo, Ondřej (referee) ; Schimmel, Jiří (advisor)
The thesis deals with the problems of closed spaces. It deals with situations where it is necessary to reduce the reverberation time in certain octave bands. It provides procedures comparing conventional method of solving by calculation of the mean sound absorption coefficient of the area and the subsequent experimental addition of acoustic absorbers which occupy different areas and method that uses an acoustic simulation software for the 3D model. It also deals with a concept of Reflection Phase Grating diffuser.
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Acoustical measurent in real environment
Mach, Václav ; Mačák, Jaromír (referee) ; Míča, Ivan (advisor)
This bachelor thesis discusses the issue of acoustical measurement. There are dierent signals described, which are used for this purposes, both MLS and esweep, compared their advantages and disadvantages and made some practical demonstrations of impulse response measurement. Furthermore, the fundamentals of reberbation time measurement are described in theory. The practical part of this thesis consists of the measurement application, written in the C++ language and mainly targeted for Linux systems. Qt multiplatform toolkit has been utilized for the GUI part.
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Primary School
Forman, Daniel ; Manová, Ludmila (referee) ; Maceková, Věra (advisor)
Thesis Theme is a primary school, namely the outbuilding primary school Havlíčkův Brod, Konečná 1884. I suggest first grade pavilion and pavilion with school canteen with kitchens. Pavilions are based on the footings. Pavilions are designed as a two-way system from the wall HELUZ. Construction of ceiling are from ferroconcrete slabs are cross reinforced, single-layer roof is flat with a classic sequence of layers. In addition to construction and process layout I solved also the statics of building in specialize of concrete structures. The following are also evaluated heat and acoustic requirements and requirements for fire safety of buildings. New pavilions are solved as wheelchair accessible. Pavilion of the first grade has two floors with 5 classes of stem, 1 vocational and 2 classes are earmarked for after-school clubs. This pavilion is connected to the connecting neck between the former pavilon A and pavilion B. Dining pavilion has one floor, which is divided in the school canteen and kitchen is connected to the connecting neck leading to the gym. The land is mildly sloping to the south side. All consstructions comply with the applicable standards and recommendations ČSN.
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