National Repository of Grey Literature 151 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
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.
Design and Realization of Acoustic Treatment of Small Recording Studio
Tkadlec, Vojtěch ; Husník, Libor (referee) ; Schimmel, Jiří (advisor)
This bachelor thesis deals with the topic of acoustic properties of an enclosed space, their detection and modification. The thesis examines the acoustic properties of a small enclosed space, which were determined by simulation using a virtual 3D model and subsequently verified by measurement. After finding out the properties, a substantial part was also devoted to their modification, where the task was to design the acoustic elements so that the resulting length of the reverberation time corresponds to the optimal values for a small recording studio. The design of the elements is followed by their construction, followed by a re-measurement of the space. Furthermore, the work summarizes the principles of modeling and simulation of 3D models.
Automation of Audio Device Measurement on APx500 Platform
Panáček, Richard ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
This bachelor thesis is focused on the options of measurement automatization on the platform APx500. This automatization should be achieved not only with the use of the measuring program APx500, but also with the use of third-party programs. In these programs, measuring projects should be created. Among many compatible programs, there are LabVIEW, VEE, and a programing environment using Visual Basic language. The thesis is divided into many parts. The first part is focused on the introduction of the APx500 program and its functions. The second part is aimed at the connecting program APx500 with third-party programs using APx API. The practical part of this thesis is about the creation of a measuring project for frequency response in program LabView. Afterwards, this thesis focuses on creating a measuring project inside Excel document, with the usage of Visual Basic language for Applications. This project is intended to measure acoustic response, impedance and Thiele-Small parameters of a loudspeaker.
Variable Two-Way Loudspeaker Cabinet - Laboratory Tool
Rehák, Jan ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
The objective of this work is to build a two-way loudspeaker system that will enable changing loudspeaker topology in both vertical and horizontal axes and to suggest two laboratory tasks. The theoretical part of this work will briefly discuss loudspeaker crossovers. Then it will discuss how topology of loudspeakers in a loudspeaker system can affect its behavior at crossover frequency. Frequency characteristics of various loudspeaker baffles will be shown. On these, the effect of a baffle’s exterior on its behavior will be discussed. A two-way loudspeaker system will be designed. The construction process and drawings of each part are also included in this work. The finished product will be tested and, following from these tests, a conclusion will be drawn about the validity of the theoretical assumptions of its design. After that, appropriate parameters of a crossover for the two-way loudspeaker system will be chosen.
Interactive Searching in Online Archive of Visual and Audiovisual Artworks
Kuře, Dominik ; Myška, Vojtěch (referee) ; Schimmel, Jiří (advisor)
This bachelor thesis focuses on development of a web application, which serves as an archive for videos. Each video has a certain amount of keywords. The application uses an already created database and a preinstalled server on which the videos are uploaded. The database was given to the author by his supervisor. Searching through the archive can be done by inputting an expression into a search bar or through a variation of filters that are based on information about each video. The results and the database as a whole are graphically represented by charts, which change their form based on given data. Videos can be played in a video player and a list of similar videos is generated. The list is based on keywords which the videos have in common. The main technologies used in the application are Node.js, React and MariaDB. A good amount of libraries are used for this application, allowing JavaScript to be the primary programming language in all phases of development. The text of this bachelor thesis can be dividen in two parts - theoretical and practical. The first part describes all the technologies and libraries used in the application. An in depth approach was taken especially on those parts of each library which are actually being used in the practical. Apart from the necessary technologies, the reader will be also introduced to libraries and systems which help a programmer with his work such as automatic formatting of code and it's backup, saving different versions of the code or adding static datatypes into JavaScript through TypeScript. The theoretical part should give the reader a summary of how browser applications work and communicate with each other. In the practical part an entire application will be built from scratch. The application will connect four different servers - front-end, back-end, database server and a server storing the videos - and allow them to communicate accordingly. The bachelor thesis also contains information about using different controllers for manipulating the browser.
Small-Size Microphone Array for Estimation of Direction of Arrival of Sound
Kubišta, Ladislav ; Honzík, Petr (referee) ; Schimmel, Jiří (advisor)
This thesis describe detection of direction receiving sound with small–size microphone array. Work is based on analyzing methods of time delay estimation, energy decay or phase difference signal. Work focus mainly on finding of angle of arrival in small time difference. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab
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.
Modeling of Linear Distortion of Audio Devices
Vrbík, Matouš ; Sysel, Petr (referee) ; Schimmel, Jiří (advisor)
Methods used for correction and modeling of frequency response of sound devices are discussed in this paper. Besides classic methods of digital filter design, more advanced and complex numerial methods are reviewed, Prony and Steiglitz-McBride in particular. This paper focuses on structure utilizing parallel sections of second-order IIR filters. Methods for calculating coefficients of this structure are presented and later implemented. For selected method, utilizing dual frequency warping, an interative algorithm for automatic calculation of parameters necessary to filter design is implemented - so called Particle Swarm Optimization. Six ways of evaluation filter design precision are presented and the results are compared. Functions realizing filter design are implemented in C++, MATLAB and Python. A VST module simulating the filter in real time is also provided.
Measurement of Non-Linear Properties of Loudspeakers
Friml, Vilém ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This thesis deals with calculation of THD dependency on signal frequency and calculation of Rub & buzz distortion using MATLAB software. Thesis includes generation of signals suited for THD measurement, playback and recording using sound card and APx series 500 device. The APx device controlling and data acquisition by MATLAB is also addressed. Loudspeaker electric model is discussed for the use of Rub & buzz measurement.
Simulation of Sound Field of Sound System with Multiple Speakers in Closed Space
Brůna, Michal ; Husník, Libor (referee) ; Schimmel, Jiří (advisor)
In this thesis basic principles of sound system design are presented. A software simulation in Matlab is written for prediction of sound field with sources of real directivity in both freefield and in a closed room using velocity potential. Reflections are simulated using mirror sources of first and second order. Frequency dependent sound absorption coefficients are implemented in the simulation. There is a GUI designed to operate on most common horizontal configurations. Those are then evaluated and advantages and dissadvantages are demonstrated using the simulation software.

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