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Two-way stereo speaker system
Kočvara, Pavel ; Polák, Ladislav (referee) ; Kratochvíl, Tomáš (advisor)
The Bachelor thesis deals with design of a passive two-way stereo speaker system with performance 50 W RMS / 8 for normal domestic use. With respect to its sensitivity 90 dB/W/m mid-range speakers Beyma 5MP50/N and tweeter Beyma T2030 were used. The enclosure is a type of bass-reflex and it is made of MDF material with internal damping from polyurethane coat.
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Design and Construction of Transmission Line Loudspeaker Cabinet
Dobiášovský, Jiří ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
Thesis is dealing with the topic of design and construction of the transmission line loudspeaker enclosures. Theoretical part is focused on speaker choice, its design elements and their influence on parameters of the speaker. Individual parameters of the speaker, mathematical equations for their determination and choice of suitable speaker for transmission line loudspeaker enclosure is furthermore discussed and defined. Principle of transmission line enclosures is discussed together with its advantages and disadvantages compared to other types of enclosures. The individual design elements and their influence on the resulting characteristics of the enclosure are described. In the practical part, with regard to the facts stated in the theoretical part of the work, a suitable speaker is selected and the subsequent design and construction of a variable transmission line speaker is described. This might serve as a teaching aid in future. Part of the work is also a description of procedures for measuring loudspeakers with multiple speakers or resonators.
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Loudspeaker Box with Variable Crossover Frequency
Tomášek, Martin ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This bachelor´s thesis deals with middle-sized loudspeaker system in D´Appolito configuration. The aim of this thesis is to design and to realize the loudspeaker system, which includes selection of suitable loudspeakers and their position in designed baffle including design of variable crossover frequency. The text is divided into a few sections, where are the points of this project described. In the first half there are briefly described basic principles of loudspeakers and design loudspeaker systems, especially 2-way loudspeakers, and specific properties of D´Appolito configuration. Then there are described principles of frequency crossovers used in loudspeaker systems and what is expected for their construction. In the second half, there is described realization of baffle itself and variable frequency crossover. Because this thesis concurs to semestral thesis, there is also a chapter about simulation. In the end there are diagrammatized the measured data of frequency and dispersion characteristics and a few dispersion characteristics for different crossing frequences.
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Compensation of loudspeaker measurements using standard baffle
Štěpáník, Jiří ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The frequency response of the loudspeaker is one of the key data that needs to be known, for example, when designing a speaker cabinet or speaker system. The frequency response should be achieved with the highest possible accuracy and with a minimum of distortion. How to achieve such characteristics is described in the standard ČSN EN 60268-5, which states as one of the ways the use of standard enclosures. Except for the standard baffle, these baffles have correction curves for the measured characteristics described in the standard. However, this does not mean that the standard baffle does not distort the measurement. The aim of this work is to analyze the distortion of measurements caused by this baffle and other elements and their compensation. The work contains a description of certain parts of the standard ČSN EN 60268-5 with focus on the standard baffle. Especially on its construction and methods of measuring the speakers mounted on it. Several test measurements were performed within the work. These measurements were performed in a anechoic chamber with speakers mounted on a modular standard baffle, which is a modification of the standard baffle which is also described in the work. The measurements performed include the measurement of frequency characteristics at different distances of the microphone from the speaker at different positions of the baffle in the anechoic chamber. The test measurements show that the modular standard baffle and anechoic chamber cause measurement distortion. In other measurements, the distortion by the anechoic chamber is minimized and the distortion caused by the base of the modular standard baffle is completely eliminated. The thesis then presents the theory of sound diffraction at the edges of a standard baffle and the theory of the extended Biot-Tolstoy-Medwin method of modeling these diffractions using numerical calculations. Based on this theory, software compensation of diffraction distortion was performed in Matlab. It is not entirely clear from the results of the compensation to what extent it can be considered successful. It can be speculated that it only works on certain frequencies. It is necessary to verify the functionality of this compensation method by another test measurement.
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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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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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Amplifier with Speaker Protection
Přibyl, Libor ; Schimmel, Jiří (referee) ; Kubánek, David (advisor)
The present work deals with the issue of speaker damage due to large displacement of the membrane at low frequencies. The main focus is the design and construction of the circuit to protect the speakers from this type of damage and the subsequent measurement of its parameters. The thesis includes theoretical predictions for the optimal design and implementation of the circuit. The work includes complete construction of equipment, including power supply and auxiliary circuits.
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Design and Implementation of Active Loudspeaker System with Digital Input
Uchytil, Filip ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
The work is focused on a design of an active loudspeaker system with a bi-amp amplifier and a digital input. There is described the theory of a loudspeaker enclosure design and its practical implementation. Furthermore the work deals with a design and construction of input circuits such as a preamplifier, Baxandall tone control, active crossover, all-pass filter and S/PDIF. On the basis of the amplifier´s theory the optimal construction of amplifiers and their design are selected. The complex design of the loudspeaker box is devised so that it would reach a maximum acoustic power during the preservation of a low distortion.
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Up-firing loudspeakers for 3D Audio
Pešek, Marko ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This bachelor theses dealing with study multichannel 3d audioformat Dolby Atmos and parameters of up–firing loudspeakers, which assures overhead audiosignal reproduction coming towards hearer. According to the knowledge is made proposal of up–firing loudspeakers, fabrication and measurement their properties.
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