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Modeling Sound Field in Closed Space at Low Frequencies
Hořák, Pavel ; Kiska, Tomáš (referee) ; Schimmel, Jiří (advisor)
This diploma thesis deals with issues of low frequency acoustics and simulation. In this work the FTDT method of simulation is used. Measuring and simulation are focused on live-sound system and are evaluated using basic sound system optimisation techniques. Main output of this work is verification of basic low-frequency acoustics principles using simulation and measuring.
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Application for Measurement of Room Impulse Responses
Vrbík, Matouš ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This paper studies problematics of room impulse response measuring. Signals appropriate for measuring are mentioned, with emphasis on stepped sine signal (sweep) and MLS signals. Measuring methods suitable for particular signals are introduced. Another parameter characterizing room qualities is reverberation time. Theoretical and practical methods for determination of this parameter are described. First part of this thesis offers solution in MATLAB environment. Functions for generating measuring signals and for subsequent processing of measured data were created. In second part of this thesis, methods were implemented in C++ language and standalone application, which uses ASIO technology, was created.
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Lossy Video Compression
Šiška, Michal ; Průša, Zdeněk (referee) ; Schimmel, Jiří (advisor)
This thesis deals with description of lossy video compression. Theoretical part of the work describes the fundamentals of the video compression and standarts for lossy as well lossless video and still image compression. The practical part follows up with design of Java program for simulation of MPEG codec.
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Loudspeaker System for Reproduction of Low Frequencies with Directional Radiation
Skvaril, Šimon ; Husník, Libor (referee) ; Schimmel, Jiří (advisor)
Final product of this work is design of speaker baffle which will have directional radiation at low frequencies. In the course of the work, propagation of sound waves and their beaviour at obstacles are described. The computational method FDTD and the K-wave toolkit for MATLAB, which uses this method, are described. In MATLAB a virtual model of speaker baffle is created and proposed solution is verified. Next step is creation of scaled model of speaker baffle on which agreement of theoretical computations with real-world measurment is verified. Final step is creation of prototype of speaker baffle,, whose parameters are measured, including polar response.
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Impedance Tube for Measuring Sound Absorption Coefficient
Raška, Adam ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
This thesis, consists of summering basic knowledge about absorption factor, methods for its measuring and construction of impedance tube for measuring with chosen method. Besides that, this thesis i salso about measuring absorbtion factor of available materials in this tube, and proposing laboratory task about absorbtion factor measurement, which should use crafted measuring equipment.
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Electric Volin with MIDI Output
Spilka, Benedikt ; Vrba, Kamil (referee) ; Schimmel, Jiří (advisor)
The main aim of this diploma thesis is to design and to construct a electric violin with MIDI output. This thesis include design and conctruction of violin pickup, violin electronic and software for translation of sound into MIDI messages. design of the instrument´s body is presented at the end of the thesis. Violin electronic include circuits for filtration, amplification, processing and AD/DA conversion of audio siganl. Software for MIDI transfer recognizes notes and translates them to MIDI messages.
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Thresholding rules for noise reduction in sound signals
Ráček, Tomáš ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The master's thesis focuses on the study of algorithms dealing with noise separation from musical signal. The first chapter is an introduction into methods which are used for noise removal of the musical signal. Furthermore, this chapter describes theory to the issue, specifically a description of transformations for converting from time to frequency domain, and finally thresholding method of spectral coefficients is explained in detail. The aim of the second chapter is an analysis of the proposed algorithm, which is engaged in testing. From the beginning fast algorithms of gradual transformation are described and then a detailed description of the algorithm as a whole. Later, this chapter deals with the selection of audio recordings and with preparation of these recordings for the actual testing. Finally, testing of audio samples is presented in the third chapter of this thesis. This chapter also concludes comparison of individual transformations, achieved results and review of algorithm.
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Measuring Loudspeaker System for Laboratory Practices
Tomešek, Jiří ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This bachelor's thesis deals with the design of a two-way speaker system and a variable baffle for a subwoofer for the purposes of demonstration measurement in the subject of Electroacoustics. The theoretical part explains the individual speakers, TS parameters and formulas for their calculation. Furthermore, various types and constructions of baffles and audio crossovers. Using the simulation program LspCAD, the designs of closed and bass reflex baffles with right and wrong parameters were fine-tuned and simulated. The proposed crossover for a two-way speaker system was also simulated. Drawing documentation was prepared for the designs. Furthermore, the baffles and crossovers were implemented, and their characteristics were measured. Finally, the existing laboratory tasks were reworked so that students could use the implemented baffles and the chosen design procedure.
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Software for audio adjustment in multiple loudspeaker system
Černý, Viktor ; Schimmel, Jiří (referee) ; Sysel, Petr (advisor)
The first part of this Master’s Thesis deals with the theory of digital signal processing and describes the JUCE library. In this part some basic operations are explained with digital audio signals, such as polarity inversion, delay and linear interpolation of signal samples. The creation of new audio applications using the JUCE library in the C++ programming language is explained too. The next parts of this thesis describe the implemented audio application that allows the user to provide the described basic operations with digital audio signals in real time. For multiple channel audio signals the channels can be processed independently.
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