|
| |
|
|
Subjective and Objective Assessment of Speech Quality
Bezdíček, Martin ; Balík, Miroslav (referee) ; Vondra, Martin (advisor)
This Bachelor's thesis is focused on subjective and objective methods for evaluation of speech quality. In the first part, the quality of transmitted speech signal and its distorting effects are given. Futher, subjective and objective methods for evaluation of speech are described. The objective methods: Signal to Noise Ratio (SNR), Segmental Signal to Noise Ratio (SSNR), the methods for evaluation in spectral area (Log Likelihood Ratio Measures and Cepstral Distance) and also Perceptual Evaluation of Speech Quality (PESQ). The next part deals with the correlation analysis which is used for the comparison of subjective and objective methods. In the last part of the bachelor thesis the results of subjective and objective methods are presented. Finally on the basis of correlation analysis with the results of subjective method, the best objective method is recommended.
|
|
|
The Influence of single harmonics or formants on timbre color perception
Klimeš, Martin ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the research of the influence of individual harmonic on the perception of sound color. An application was created with a questionnaire in which respondents assessed a total of 29 samples on different bipolar scales.The samples were either modeled by additive synthesis or created by modifying musical instruments. The aim was to investigate how and what combinations of higher harmonic affect the perception of sound color. The experiment is based on the semantic differential method. The samples were divided into several groups and within these groups they were compared and related to the expected color perception.
|
|
|
The Evaluation of masking of harmonic components in a mixture
Kovanda, Jindřich ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis deals with design and creation of listening test in which its respondents were setting certain harmonic of the tone to mixture of up to 16 harmonics. The respondents were setting intensity of the harmonic to the border position, in which the harmonic was not masked by the other harmonics in the tone and in which the harmonic stood up from the mixture. The respondents were stetting the harmonics from the first to sixteenth, in various types of the spectrum, pitch and intensity of the tone. Based on the results relations were found which determine how the perception of masking of harmonics vary with their order in the spectrum.
|
|
|
Optimalization of Audio Reproduction Chain for Hearing Tests
Halaš, Rostislav ; Schimmel, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
This project describes basic steps leading to the solution of a problem associated with a poor quality of played recordings in the listening room of the Škoda Auto co. . Firstly, the main technical parameters of the reproduction chain elements are resumed. Secondly, the basics of the room acoustics, such as the distribution of the sound field in a bordered space, are explained. On the basis of theoretical relations, the main modes of a cubic room are calculated. Then, software for acoustic response computing is used to simulate various options of both room idealization (room size, absorption coefficient, etc.) and listening point location. Simulations are compared with results gained by measurement. On the basis of this measurement, the quality of acoustics of the listening room is evaluated. In next chapters, the process of the optimalization of the audio chain and setup of the Automotive Sound Quality software are summarized. To conclude, the results are assessed and further steps based on the project are proposed.
|
|
|
Analysis of pitch perception depending on the spectrum
Slávik, Martin ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the research of the influence of individual harmonic components on the perception of sound height. As a part of the work has been made an internet questionnaire on a web address www.analyzavyšek.9e.cz, where individual respondents completed listening test compound of 46 samples. This experiment is based on semantic differential method. Individual samples are compound of sine wave – tone and examined sample, which respondents evaluates on three bipolar scales. The samples were either modelled by additive synthesis or modified sampled sounds of instruments. Individual samples were divided to four major groups and other minor groups for clarity. The purpose was to find which parts, combinations and harmonic components of sound and tone can affect perception of tone height.
|
|
|
The analysis of psychoacoustic perception of chords composed from different full and variously colored signals
Vejmělka, Daniel ; Musil, Jaroslav (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the impact of frequency spectrum of musical sounds on psycho-acoustical perception of the listener. It studies how differently filled harmonic spectrums can influence listener’s ability to determine individual notes in a chord and what influence, on recognizability of a chord, inharmonic elements have. It explores different methods of psycho-acoustic measurements and further data processing. The experiment is based on a method of paired comparisons and was realized in a form of listening test with more than 100 participants. The test is focused on typical representatives of different groups of musical instruments. It studies the impact of different colors of sound used in different types of chords. It further deals with statistical processing of the recovered data.
|
|
|
The Evaluation of masking of harmonic components in a mixture
Kovanda, Jindřich ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis deals with design and creation of listening test in which its respondents were setting certain harmonic of the tone to mixture of up to 16 harmonics. The respondents were setting intensity of the harmonic to the border position, in which the harmonic was not masked by the other harmonics in the tone and in which the harmonic stood up from the mixture. The respondents were stetting the harmonics from the first to sixteenth, in various types of the spectrum, pitch and intensity of the tone. Based on the results relations were found which determine how the perception of masking of harmonics vary with their order in the spectrum.
|
|
|
Analysis of pitch perception depending on the spectrum
Slávik, Martin ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the research of the influence of individual harmonic components on the perception of sound height. As a part of the work has been made an internet questionnaire on a web address www.analyzavyšek.9e.cz, where individual respondents completed listening test compound of 46 samples. This experiment is based on semantic differential method. Individual samples are compound of sine wave – tone and examined sample, which respondents evaluates on three bipolar scales. The samples were either modelled by additive synthesis or modified sampled sounds of instruments. Individual samples were divided to four major groups and other minor groups for clarity. The purpose was to find which parts, combinations and harmonic components of sound and tone can affect perception of tone height.
|
|
|
The Influence of single harmonics or formants on timbre color perception
Klimeš, Martin ; Indrák, Michal (referee) ; Jirásek, Ondřej (advisor)
This thesis is dealing with the research of the influence of individual harmonic on the perception of sound color. An application was created with a questionnaire in which respondents assessed a total of 29 samples on different bipolar scales.The samples were either modeled by additive synthesis or created by modifying musical instruments. The aim was to investigate how and what combinations of higher harmonic affect the perception of sound color. The experiment is based on the semantic differential method. The samples were divided into several groups and within these groups they were compared and related to the expected color perception.
|
guest ::
