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Comparison of noise generated by differently constructed vents
Bernard, Jan ; Doložílek, Miroslav (referee) ; Jedelský, Jan (advisor)
This diploma thesis deals with comparing noise levels of three side vents of different constructions, which are used for distribution and directing of ventilation air in a cabin of an automobile. The fundamental knowledge of the physical and physiological acoustics is described in the introduction part of this study. Following the introduction part there is a brief explanation of the car air conditioning system (HVAC system) as well as are explained the acoustic properties of specific elements of this system. The study also deals with dividing ventilation vents and describes the vast traceable types of automobile vents. Prior to the description of the experiment, which was conducted as a part of this study, the procedures and results of the measurements carried out in other theses are explained. Measurement of noise levels of the compared vents was carried out in a semi-anechoic chamber under the ČSN ISO 3475 standardization. To clarify increase of noise generated by the vent in an interior of an automobile, additional measurement of noise was carried out in a cabin of Porsche Cayenne 2018. From the gathered results we can conclude that under the constant flow, (of 60 square meters per hour) louder vents are those with higher pressure loss. This pressure loss is dependant primarily on the speed of the flow in the vent, as well as on the number and the adjustment of the deflectors. In a cabin of an automobile, the noise produced by the vent is negligible in comparison with total noise in an interior of a car. However, in the area surrounding the air flowing out from the vent, (approximately 0,7 meters from it) the level of acoustic pressure increases significantly.
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Human hearing sensitivity assesment
Tinka, Dominik ; Sekora, Jiří (referee) ; Škutková, Helena (advisor)
Bachelor thesis aims to evaluate changes of sensitive human hearing through created mobile application. According to obtained teoretical knowledges mobile application provide audiometrical measurements. In connection with this is described adjustments of sound outcomes of mobile, which is set in pursuance of calibrate unit. In the next part is described methodics of measuring and processing measured data. Static evaluation is processed on collected measured data from one proband and group of probands. Measurements on one proband were repeated for couple of days. The end of this thesis discusses about obtained results, which challenges the hypothes about sensitivity of hearing.
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Demands of the Teacher's Proffesion on the Teachers' Voice
Králová, Michaela ; Tichá, Alena (advisor) ; Koverdynský, Luděk (referee)
This dissertation thesis deals with the demands on teachers' voice and proper use of voice in the teacher's profession. The whole thesis consists of two parts: theoretical and practical. The theoretical part is divided into nine sections: the anatomy and physiology of the vocal tract, voice developement, comparison of spoken and singing voice, psychological impact on voice, voice defects and hygiene, voice reeducation, methods of voice diagnostics and voice acoustics. The research part presents the findings of acoustic voice measurement. Students (only women) of Faculty of Education in Prague participed in the research. The objective of this part was to asses the quality of students' voice and their voice readiness for future teaching.
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Comparison of noise generated by differently constructed vents
Bernard, Jan ; Doložílek, Miroslav (referee) ; Jedelský, Jan (advisor)
This diploma thesis deals with comparing noise levels of three side vents of different constructions, which are used for distribution and directing of ventilation air in a cabin of an automobile. The fundamental knowledge of the physical and physiological acoustics is described in the introduction part of this study. Following the introduction part there is a brief explanation of the car air conditioning system (HVAC system) as well as are explained the acoustic properties of specific elements of this system. The study also deals with dividing ventilation vents and describes the vast traceable types of automobile vents. Prior to the description of the experiment, which was conducted as a part of this study, the procedures and results of the measurements carried out in other theses are explained. Measurement of noise levels of the compared vents was carried out in a semi-anechoic chamber under the ČSN ISO 3475 standardization. To clarify increase of noise generated by the vent in an interior of an automobile, additional measurement of noise was carried out in a cabin of Porsche Cayenne 2018. From the gathered results we can conclude that under the constant flow, (of 60 square meters per hour) louder vents are those with higher pressure loss. This pressure loss is dependant primarily on the speed of the flow in the vent, as well as on the number and the adjustment of the deflectors. In a cabin of an automobile, the noise produced by the vent is negligible in comparison with total noise in an interior of a car. However, in the area surrounding the air flowing out from the vent, (approximately 0,7 meters from it) the level of acoustic pressure increases significantly.
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Human hearing sensitivity assesment
Tinka, Dominik ; Sekora, Jiří (referee) ; Škutková, Helena (advisor)
Bachelor thesis aims to evaluate changes of sensitive human hearing through created mobile application. According to obtained teoretical knowledges mobile application provide audiometrical measurements. In connection with this is described adjustments of sound outcomes of mobile, which is set in pursuance of calibrate unit. In the next part is described methodics of measuring and processing measured data. Static evaluation is processed on collected measured data from one proband and group of probands. Measurements on one proband were repeated for couple of days. The end of this thesis discusses about obtained results, which challenges the hypothes about sensitivity of hearing.
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Demands of the Teacher's Proffesion on the Teachers' Voice
Králová, Michaela ; Tichá, Alena (advisor) ; Koverdynský, Luděk (referee)
This dissertation thesis deals with the demands on teachers' voice and proper use of voice in the teacher's profession. The whole thesis consists of two parts: theoretical and practical. The theoretical part is divided into nine sections: the anatomy and physiology of the vocal tract, voice developement, comparison of spoken and singing voice, psychological impact on voice, voice defects and hygiene, voice reeducation, methods of voice diagnostics and voice acoustics. The research part presents the findings of acoustic voice measurement. Students (only women) of Faculty of Education in Prague participed in the research. The objective of this part was to asses the quality of students' voice and their voice readiness for future teaching.
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Current situation of loudness of sound signals
Kravařík, Jindřich ; URBAN, Ondřej (advisor) ; DVOŘÁK, Aleš (referee)
The topic of this thesis is the permanently worsening situation in the area of loudness and dynamic range of sound signals being delivered to customers, both on classic media and in broadcast. It discusses the reasons and consequences of the current situation. These problems are global and they have impact on every listener and viewer. Extremely varying loudness of broadcast and terrifying state of some records being published at big media houses are a target of complaints for a long time. At the time of writing, solutions to improve the situation are finally emerging. These solutions are evaluated in the last part of this thesis and using them examples of improperly treated dynamics are given.
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