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Wavefield Synthesis for Linear Loudspeaker Array
Panáček, Richard ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This master thesis is meant to create a function for processing audio signals with Wavefield Synthesis for linear loudspeaker array. The text focuses on general issues of Wave Field Synthesis and practical design of 2.5D synthesis. It introduces Huygens’ principle followed by Rayleigh’s Theorem together with Rayleigh’s integrals. True design realizations are introduced based on theoretical procedures. The text states advantages and disadvantages of Wave Field Synthesis with linear loudspeaker array and also recounts solutions of some of the problems. The practical part of this thesis is devoted to designing two functions of Wave Field Synthesis inside the programming platform Matlab. The first function serves for processing signals from audio recordings and the second one for processing signals in real time. Proper functioning of procedures used in this thesis is then tested by a listening test.
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Implementation of symmetric bloc cipher AES in modern processors
Škoda, Martin ; Balík, Miroslav (referee) ; Rášo, Ondřej (advisor)
The main aim of master's thesis is usage of new instructions from instruction set called Intel® Advanced Encryption Standard New Instructions (AES-NI), which is available on processors with code name Westmere and newer. In theoretical part, there are described symmetric block ciphers and their operational modes. Cipher AES is described in details, especially used block transformations, key expansion and equivalent inverse cipher. Next topic is description of instructions of AES-NI instruction set – their function is explained using pseudo codes of instructions and there are examples of their usage in code. Further in work, dynamic-link library is created, which implements cipher AES with key sizes 128, 192 and 256 bites and implements operational modes described in theoretical part. Library functions are called from Matlab by scripts and their functionality is proved by checking test vectors values, which are provided in publications of National Institute of Standards and Technology.
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Influence of Disposition of Opera Stage and Orchestra Pit on Theatre Acoustics
Berky, Martin ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This semestral thesis describes messurement of reverberation time, monaural and binaural impluse response Divadlo na Orlí during positioning of sound-source in orchestra pit and on the stage. Theoretical part describes messurement of reverberation time and objectiv criteria of soundfield quality in concert and opera. The practical part describes messurement in Divadlo na Orlí and computations in program Matlab. The thesis compares results in various configuration of theratre hall and describes common advices for operas in Divadlo na Orlí.
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Design and Realization of Acoustic Solution for Listening Room
Burda, Jan ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This work is focused on the problem of room acoustics and its analysis options. It describes the basic criteria of acoustic quality space, commonly used materials and acoustic tiles. It also deals with modeling and acoustic analysis of space using EASE. The third part of thesis is a detailed description of the design of acoustic elements based on resonance principle. The last part deals with the measurement of the reverberation time.
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Video mixer/translator for web-based videoconference system
Hutar, Jan ; Balík, Miroslav (referee) ; Číka, Petr (advisor)
Bachelor s thesis specialises in a basic description, comparing and processing of video standards H.264 and VP8 in real time. Particularly it concerns a support of videoconfe- rence systems working with those mutually incompatible standards. The work enquires and tests two most considerable software devices convenient with basic requirements for working with video in real time and available with LGLP licence respectively FFmpeg and GStreamer. The thesis suggests practice video mix implementation of data input and the way of code translation into required outgoing stream. FFmpeg tool has been used for realization and message of mixer/translator and simple interface has been established available from web browser with assistance of HTML, PHP and Javascript.
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Acoustic Signal Recording and Processing Using B-Format Technology
Kurc, David ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This bachelor’s thesis is focused on the system of recording and processing of acoustics signals called Ambisonics. It describes single sections of this system in the chain of acoustic signal processing. At most it is aimed at the B-format technology as the main ambisonic instrument, its encoding from the signals recorded with the special microphone capsule of the soundfield type or with help of encoding equations and its decoding into single speaker channels of various speaker arrays. The UHJ transmission format is also mentioned. The application B-format Decoder was created in the MATLAB programming environment. It consists of several functions and has friendly user interface, which provides the processing and decoding of B-format components for the speaker array with entered parameters. Among others this interface ensures loading, displaying, analysis and playback of source and resulting acoustic signals.
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Simulations of auditory space and azimuth&distance of sound source, for multichannel sound systems
Orlovský, Kristián ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This thesis is aimed at simulation of auditory space. It describes the most frequently used panning method: Vector Base Amplitude Panning. Also is focused on image source method, which allows computing the parameters of direct sound wave and reflections in rectangular room. This method is compared with ray–tracing method, which is also often used. It deals with the matter of the frequency – dependent absorption of materials in reflection of the sound wave against the wall. On the basis of these information two applications were designed in MATLAB development environment. The first one allows the simulation of auditory space. The other one is the application for sound source panning by its azimuth and distance.
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Sound panning in multichannel sound systems
Orlovský, Kristián ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This thesis is aimed at simulation of auditory space. The first part is based on theoretical information and explains two of the most frequently used sound panning methods: Vector Base Amplitude Panning and Ambisonics. It shows the ways for sound panning by these methods. In next step are methods compared based on theoretical information and simulations in Matlab environment and one most suitable method is chosen for using in second part. This part describes image source method which enables parameters computation of direct sound wave and optional number of early reflections in rectangular room. Also is focused on problem of frequency dependent reflections. In conclusion it offer knowledge obtained by simulation of different auditory spaces with different topology.
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Laboratory Practices Focused on Loudspeaker System Design
Vydarený, Ján ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This work deals with creating the bases for the laboratory tasks of designing the speaker system. The theoretical part explains the TS parameters and the equations for their calculation, the different types of sounding and switches. The work deals with selecting a suitable high-tone speaker to the specified low-tone speaker. Closed and bass reflex simulations were performed in the LspCAD. Similarly, simulation of the loudspeaker network was created in this program too. A loudspeaker box, crossover and subsequent measured parameters of the resulting repro system were produced. The last step was to modify the lab instructions
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