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Loudspeaker Box for Wavefield Synthesis
Naňák, Pavel ; Kubánek, David (referee) ; Schimmel, Jiří (advisor)
Purpose of this work is to design active loudspeaker system as a source of sound proper for wavefield synthesis. Loudspeaker system is considerate as a singleband and its length should not overlap 15cm. System should be designed at the best in parameters like frequency characteristic and directional characteristic. Part of work is dedicated to theoretical aspects, explanation of wavefield principles itself and its usage on the field of surround sound, further this work concerns aural transducers, especially electrodynamic one, which is used in this work, and the last topic is about baffle-board for loudspeakers. Hereinafter there are laid two proposals of baffles, one conception is closed baffle and second is bassreflex baffle. Both of those baffle conception are simulated in program LEAP-5 and are optimized for this current work. All construction possibilities introduced in this work are digestedly documented in appendix. Special attention is dedicated to right choice of aural transducer for this loudspeaker and to description of its attributes, there are discussed pro and cons of every chosen transducer and its suitability for this work. Electronic part of work is designing of amplifier and power source suitable for at least four of loudspeakers. Amplifier is modified for switching input level of signal between -10 dBu and +4 dBu, this range is reached by switching the amplification of amplifier. Amplifier is realized in class D, because of the demands on small the size of the system. Amplifier is powered by external source designated to be small and effective at the same time. Each module of power source and amplifier has their schemes and designs of printed circuit boards are documented in appendix.
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Loudspeaker Box for Laboratory Measurements of Loudspeaker Impedance
Nevole, Tomáš ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
In this thesis there are solved problems of design and construction of a universal modular loudspeaker box, which should serve for laboratory measurements of broadband electro-magnetic loudspeaker’s impedance. These measurements should demonstrate how the electric parameters are changed by changing the acoustic impedance of surrounding into which the speaker transmits. In the first part there is explained necessary theory for solving the task, such as way of sound’s transmission in the environment, variable sorts of speakers and their characteristics. A special focus is given to description of the electro-magnetic speaker’s parameters and construction that was used for the loudspeaker box. Then there are introduced needed mathematical formulas for algebraic design of the loudspeaker box, various types of the loudspeaker boxes (open, closed, vented) and their parameters. In this thesis there is also solved the problem with leaks and settled the matter, if it is better to build one modular box or 2 or 3 separate boxes. Most important characteristics are the impedance characteristics for this thesis but the SPL characteristics are also included. Unfortunately the simulating programs couldn’t generate the hodographs of impedance. After the algebraic calculations, in the thesis there are presented outputs from simulation programs Unibox 408 and WinISD 0.6. The outputs also are compared with the algebraic calculations. In the last part of the thesis there is already described the own construction of the loudspeaker box and presented results from the box’s measuring in the anechoic chamber (in the laboratory of electro-acoustic). The measuring of the modular impedance characteristic was realized on the single speaker and all the boxes. The measuring of the SPL (sound pressure level) characteristic was realized on the boxes only. All these results are compared with the calculations and simulations and the inaccuracies are substantiated in the end. The comparing of the manufacturer’s characteristics with the measured characteristics is also included.
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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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Loudspeaker Box for Wavefield Synthesis
Naňák, Pavel ; Kubánek, David (referee) ; Schimmel, Jiří (advisor)
Purpose of this work is to design active loudspeaker system as a source of sound proper for wavefield synthesis. Loudspeaker system is considerate as a singleband and its length should not overlap 15cm. System should be designed at the best in parameters like frequency characteristic and directional characteristic. Part of work is dedicated to theoretical aspects, explanation of wavefield principles itself and its usage on the field of surround sound, further this work concerns aural transducers, especially electrodynamic one, which is used in this work, and the last topic is about baffle-board for loudspeakers. Hereinafter there are laid two proposals of baffles, one conception is closed baffle and second is bassreflex baffle. Both of those baffle conception are simulated in program LEAP-5 and are optimized for this current work. All construction possibilities introduced in this work are digestedly documented in appendix. Special attention is dedicated to right choice of aural transducer for this loudspeaker and to description of its attributes, there are discussed pro and cons of every chosen transducer and its suitability for this work. Electronic part of work is designing of amplifier and power source suitable for at least four of loudspeakers. Amplifier is modified for switching input level of signal between -10 dBu and +4 dBu, this range is reached by switching the amplification of amplifier. Amplifier is realized in class D, because of the demands on small the size of the system. Amplifier is powered by external source designated to be small and effective at the same time. Each module of power source and amplifier has their schemes and designs of printed circuit boards are documented in appendix.
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Loudspeaker Box for Laboratory Measurements of Loudspeaker Impedance
Nevole, Tomáš ; Káňa, Ladislav (referee) ; Schimmel, Jiří (advisor)
In this thesis there are solved problems of design and construction of a universal modular loudspeaker box, which should serve for laboratory measurements of broadband electro-magnetic loudspeaker’s impedance. These measurements should demonstrate how the electric parameters are changed by changing the acoustic impedance of surrounding into which the speaker transmits. In the first part there is explained necessary theory for solving the task, such as way of sound’s transmission in the environment, variable sorts of speakers and their characteristics. A special focus is given to description of the electro-magnetic speaker’s parameters and construction that was used for the loudspeaker box. Then there are introduced needed mathematical formulas for algebraic design of the loudspeaker box, various types of the loudspeaker boxes (open, closed, vented) and their parameters. In this thesis there is also solved the problem with leaks and settled the matter, if it is better to build one modular box or 2 or 3 separate boxes. Most important characteristics are the impedance characteristics for this thesis but the SPL characteristics are also included. Unfortunately the simulating programs couldn’t generate the hodographs of impedance. After the algebraic calculations, in the thesis there are presented outputs from simulation programs Unibox 408 and WinISD 0.6. The outputs also are compared with the algebraic calculations. In the last part of the thesis there is already described the own construction of the loudspeaker box and presented results from the box’s measuring in the anechoic chamber (in the laboratory of electro-acoustic). The measuring of the modular impedance characteristic was realized on the single speaker and all the boxes. The measuring of the SPL (sound pressure level) characteristic was realized on the boxes only. All these results are compared with the calculations and simulations and the inaccuracies are substantiated in the end. The comparing of the manufacturer’s characteristics with the measured characteristics is also included.
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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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