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Loudspeaker System for Laboratory Measurements of Polar Patterns
Morkus, Filip ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
In the first part the attention is aiming to the choice of suitable loudspeakers. For this choice it was necessary to set required criteria and parameters. The aim of the system was to have as wide reproducibility range of frequency as possible but on the other hand not to be too large. The other criterion was the quality of the loudspeakers and its price. In the second part there was frequency crossover suggested according to the parameters of the chosen loudspeakers. This was suggested for low frequency spectrum as well as for high frequency spectrum. When determining the dividing frequency there were thought over producer’s recommendations and frequency characteristics of the loudspeakers so that the dividing frequency was not set in the place where the loudspeaker does not have “constant” character. The third part concerns the construction of the loudspeaker case. There one can find more details about the construction of the loudspeaker system called D´Appolito and its constructional requirements. This part was kept to the previous parts because integrating “D´Appolito” needs setting the distance between the loudspeakers according to the dividing frequency. It was also necessary to count with their size. According to the loudspeakers parameters it was possible to calculate the capacity of the loudspeaker case, also its shape was said and geometric proportions were calculated. Then everything was simulated in suitable software. In the last part the complete loudspeaker system was measured in an anechoic room. There were the direction characteristics and frequency characteristics measured there. The results of the measuring were compared with the software simulations.
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Microphone arrays for spatial separation of acoustic signals
Grobelný, Petr ; Schimmel, Jiří (referee) ; Míča, Ivan (advisor)
The goal of this master’s thesis is to explore the possibilities of multichannel localization of acoustic signal sources and their following application on a real signal localization and separation, using Beamforming methods. During this thesis two beamforming methods were selected, namely Delay and Sum a Constant Directivity Beamforming - Circular Arrays, and were applicated on real environment signals using two microphone arrays’ geometries ULA (Uniform linear array) and UCA (Uniform Circular array).
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Application for Measurement of Musical Instruments Directional Characteristics
Ustohalová, Iveta ; Orlovský, Kristián (referee) ; Mach, Václav (advisor)
This bachelor thesis is focused on the directional charateristics of acoustics music instruments measurements. Compilalation of measuring apparatus including microphone array and the individual steps of measurement and post-processing of audio recordings in *.wav format using program created in MATLAB and ment for this purpose is described. The output are graphs showing the directional charakteristics of selected instruments - violin, clarinet, guitar and accordion in selected one-third octave bands. The measurement results are interpreted and if available, compared with results given in literature.
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Assemblies for ambient microphone techniques
Šesták, Petr ; Schimmel, Jiří (referee) ; Jirásek, Ondřej (advisor)
For proper understanding of a function of individual ambient microphone techniques, the presented bachelor’s thesis first describes, among other things, the principles of the behaving of microphones and selected pair techniques. Furthermore, the work describes the process of design and then manufacture of two constructions for ambient microphone techniques. It focuses on their properties, function and differences between them, for example in applications. It contains the marking of the directionality of individual ambient techniques.
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Analysis of the spectra of violas with respect to their different bodies
Smola, Ondřej ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This work focuses on the spectral analysis of three different violas, the modern one, the renaissance one and viola da gamba. Further the work focuses on the formant areas, resonance modes of its resonance corpus and how the resonance modes influence the tembre of the instruments. The theoretical part deals with the history of viola, acoustic-mechanical features, which influence the wood resonance. The practical part focuses on creating the graphic forms of required data needed for spectral analysis, identifying the resonance modes of the instruments and directional characteristics. The sound spectrums of all instruments are compared across the whole practical part. The practical part contains spectrograms, graphs of LPC analysis, graphs of directional radiation and table with formant frequencies of both instruments.
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D'Appolito loudspeaker enclosure and its measurement
Dočekal, Ondřej ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This bachelor’s thesis deals with a modular two-way speaker system with two mid-bass speakers in a D’Appolito arrangement. Both the effect of the D’Appolito arrangement on the directional characteristics and the effect of the relative position of the loudspeakers on these characteristics are investigated here. Part of this work is also a theory that explains basic knowledge about speaker systems and their parts, and which also clarifies the meaning of this work.
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