Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 14

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
Wyszukiwano:
w słowach kluczowych:  sound quality
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
The results of research on the sound quality of various kinds of music as well as speech signals transmitted via Digital Audio Broadcasting Plus system are presented. The results showed that bitrate values significantly influence the results of quality assessment, i.e. the overall audio quality as well as a timbre are dependent on the bitrate. The additional conclusion is that the CCR method is more accurate for sound assessment for higher bitrate values and this fact has been verified by standard deviation values of obtained results. The speech signals were additionally examined with PESQ method. The results have shown that the assumed quality of 4 MOS for speech could be achieved at 48 kbps. This fact was confirmed by both: subjective and objective research.
EN
The study makes an attempt to model a complete vibrating guitar including its non-linear features, specifically the tension-compression of truss rod and tension of strings. The purpose of such a model is to examine the influence of design parameters on tone. Most experimental studies are flawed by uncertainties introduced by materials and assembly of an instrument. Since numerical modelling of instruments allows for deterministic control over design parameters, a detailed numerical model of folk guitar was analysed and an experimental study was performed in order to simulate the excitation and measurement of gitar vibration. The virtual guitar was set up like a real guitar in a series of geometrically non-linear analyses. Balancing of strings and truss rod tension resulted in a realistic initial state of deformation, which affected the subsequent spectral analyses carried out after dynamic simulations. Design parameters of the gitar were freely manipulated without introducing unwanted uncertainties typical for experimental studies. The study highlights the importance of acoustic medium in numerical models.
EN
The paper shows a study on the relationship between noise measures and sound quality (SQ) features that are related to annoyance caused by the traffic noise. First, a methodology to perform analyses related to the traffic noise annoyance is described including references to parameters of the assessment of road noise sources. Next, the measurement setup, location and results are presented along with the derived sound quality features. Then, statistical analyses are performed to compare the measurement results and sound quality features. The included conclusions are focused on showing that the obtained loudness values, regardless of the used system, are similar in a statistical sense. Contrarily, sharpness, roughness and fluctuation strength values differ for the tools employed.
PL
W artykule omówiono założenia piątej część normy PN-B-02151 dotyczące klasyfikacji akustycznej budynków mieszkalnych oraz kryteria oceny akustycznej terenów przeznaczonych pod budownictwo mieszkaniowe. Wymieniono wymagania i klasyfikacje akustyczne w innych państwach. Wskazano też na czynnik subiektywnej oceny izolacyjności.
EN
The article presents the assumptions for part 5 of PN-B-02151 concerning acoustic classification of residential buildings and criteria for sound quality assessment of areas/sites designated for construction of residential buildings. There is a specification of requirements and classification of acoustic performance in other countries. Also, the subjective aspect of evaluation of soundproofing is mentioned.
EN
Human quality of life is constantly increasing, and so does the comfort of travel by various means of public transport, especially rail transport. One of the more crucial criteria for assessment of travel comfort is vibroacoustic comfort. This aspect is also substantial among rail vehicle operators and manufacturers. Sound quality evaluation is related to psychoacoustic indicators, but reducing the levels of acoustic pressure does not always correlate to increased quality of the perceived sound and improvement of human sound perception. Moreover the cause of unpleasant noise has to be taken into consideration. In many examples it is induced by specific vibrations and/or friction forces through components. The following article presents experimental research carried out in the in-situ conditions, testing the quality of work carried out by tram articulations considering vibroacoustic emissions. Several measurements were taken of vibroacoustic signals in several urban rail vehicles of the same type. Two different trams were chosen for analysis and their vibroacoustic emission levels as well as sound quality parameters were compared. One of the more crucial aspects of the research was to determine the dependency between vibrations around the area of articulations and squealing noise. The results indicate a large correlation between signals and deterioration in the work quality of the articulation in the given tram. Moreover, the authors suggest expanding on currently carried out maintenance in order to minimise inconvenient vibroacoustic phenomena during use.
EN
The aim of the study was to assess whether four psychoacoustic parameters (sharpness, roughness, fluctuation strength and tonality) are useful in describing the perceived annoyance of selected noise sources with respect to an objective assessment based on the acoustics standards. Second goal was to verify if the perceived annoyance of such noises correlates with dominant frequency in electroencephalography (EEG) frequency bands. Twenty sound sources, varying in the degree of nuisance, have been assessed by 178 respondents in an Internet-based psychoacoustic test. Obtained annoyance grades were correlated with calculated psychoacoustic and normative parameters and the positive correlation between perceived annoyance and three psychoacoustic parameters (sharpness, roughness and fluctuation strength) was found. In the second part EEG study during listening of recorded sounds was performed on 18 healthy volunteers. Spearman’s rank correlation confirmed that dominant frequencies in alpha (7-14 Hz) and beta2 band (20-30 Hz) were rising with the increasing annoyance of the sounds. Results obtained may be useful in specifying and clarifying permissible noise levels for annoying sounds.
PL
Celem prac było zbadanie czy psychoakustyczne parametry takie jak ostrość, szorstkość, siła fluktuacji, tonalność mogą być użyteczne do opisu uciążliwości wybranych źródeł hałasu, w odniesieniu do obiektywnej oceny opartej o akustyczne standardy. Drugim celem pracy było sprawdzenie, czy postrzegana uciążliwość tych dźwięków koreluje z częstotliwościami dominującymi w pasmach częstotliwości stosowanych w elektroencefalografii (EEG). W pierwszej części badań 178 osób wypełniło ankietę, oceniając uciążliwość prezentowanych dźwięków. Otrzymane oceny zostały skorelowane z wyliczonymi psychoakustycznymi i normatywnymi parametrami. Potwierdzono, że wraz ze wzrostem wartości parametrów takich jak ostrość, szorstkość i siła fluktuacji, wzrasta także postrzegana przez słuchaczy uciążliwość dźwięków. W drugiej części eksperymentu wykonano badania EEG 18 osób podczas odsłuchu powyższych 20 nagrań. Test korelacji rang Spearmana potwierdził, że dominujące częstotliwości w paśmie alfa (7-14Hz) i beta2 (20-30Hz) wzrastały wraz ze wzrostem średniej oceny uciążliwości. Wyniki przeprowadzonych badań mogą być przydatne do doprecyzowania parametrów oceny hałasu i ich dopuszczalnych wartości.
7
Content available remote Interfejs MIDI w organach piszczałkowych
PL
Celem badań jest stwierdzenie wpływu sterowania interfejsem MIDI piszczałkami organów na jakość dźwięku.
EN
The aim of the study is to determine the impact of MIDI interface control of pipe organ on sound quality.
EN
The analysis of available literature indicates that tests of products sound quality, which would not involve participation of groups of listeners supposed to evaluate the sounds emitted by these products, are neither carried out in Poland, nor in the world. That results in the fact that the products sound quality is determined on the basis of psychoacoustic information and comprises both objective and subjective factors of sound perception. With reference to those factors and to different life cycles of the machine, an original definition of the “sound quality of the machine” has been developed and presented in this article. The global index of the acoustic quality of the machine, accounting for the relations between the noise level at the workstation and the selected parameters characterising both the machine’s sound activity and the working environment, was adopted as the measure of the sound quality of the machine. The experiments that followed confirmed the appropriateness of the assessment made with the use of the global index of acoustic quality.
9
Content available remote Metoda wstępnej oceny akustycznej sal sportowych na etapie projektowania
PL
Zamknięte obiekty sportowe są pomieszczeniami, gdzie zrozumiałość mowy i poziom hałasu mają znaczący wpływ na komfort pracy, a nawet bezpieczeństwo osób przebywających. Stosowanie adaptacji akustycznych wydaje się często niezbędne, ale jest rzadko stosowane. W artykule przedstawiono wskaźnikową metodę wstępnej oceny jakości akustycznej pomieszczeń sportowych na etapie projektowania.Metoda podaje, w jaki sposóbmożna dobrać parametry architektoniczno-akustyczne, aby jakość akustyczna pomieszczenia sportowego była odpowiednia do potrzeb odtwarzania dźwiękówmowy. Metoda także przybliża architektomi projektantom ewentualne zagrożenia mające wpływ na warunki akustyczne w pomieszczeniach sportowych.
EN
Closed sport enclosures are rooms, where the speech intelligibility and noise levels influence significantly the working comfort and safety of working people inside. The use of acoustic adaptation appears often necessary, but it is rarely used. In the article the index method of initial assessment of acoustical quality of sport enclosures at the designing stage. The method specifies how to choose the architectural and acoustic parameters to the acoustic quality of sports facilities was appropriate to the needs of reproducing speech. The method also brings architects and designers to the possible risks that affect the acoustic properties in the sport enclosures.
EN
During operation, construction machines generate high noise levels which can adversely affect the health and the job performance of operators. The noise control techniques currently applied to reduce the noise transmitted into the operator cab are all based on the decrease of the sound pressure level. Merely reducing this noise parameter may be suitable for the compliance with the legislative requirements but, unfortunately, it is not sufficient to improve the subjective human response to noise. The absolute necessity to guarantee comfortable and safe conditions for workers, requires a change of perspective and the identification of different noise control criteria able to combine the reduction of noise levels with that of psychophysical descriptors representing those noise attributes related to the subjective acoustical discomfort. This paper presents the results of a study concerning the “customization” of a methodology based on Sound Quality for the noise control of construction machines. The purpose is to define new hearing-related criteria for the noise control able to guarantee not only reduced noise levels at the operator position but also a reduced annoyance perception.
EN
This paper describes the results of a study aimed at developing and validating a prediction model to assess the annoyance conditions at the operator station of compact loaders by using noise signal objective parameters only. For this purpose, binaural measurements were carried out on 41 compact loaders, both in stationary and real working conditions. The 62 binaural noise recordings were objectively analysed in terms of acoustic and psychoacoustic parameters and then divided into 9 groups and used in specific jury tests to obtain the subjective annoyance scores. Finally, multiple regression technique was applied to the first 6 groups of noise stimuli to develop the model while the remaining groups were used to validate it.
EN
The work presents a comparison of some sound attributes perceived at a multichannel and stereo playback of musical recordings. The width of the virtual source, coherence impression, total size of sound scene, general quality and balance were the subjects of interest after the format reduction in accordance with the ITU recommendation. The results showed that evaluation of these attributes depends on the way the original audiosphere has been created in the surround system, for example, for a narrow virtual source the mix-down process causes only a small change in its size but for a broad source the observed degradation is significant. In addition, different ways of conversion from the multichannel to stereo format have been tested for compatibility.
PL
W pracy dokonano badania jakości dźwięku sześciu wzmacniaczy akustycznych: jednego tranzystorowego (refencyjnego) i pięciu lampowych. Przeprowadzono cykl badań subiektywnych i obiektywnych. W trakcie badań obiektywnych sprawdzono podstawowe parametry elektryczne wzmacniaczy oraz wykorzystano komputerowy model psychoakustyczny. W ramach badań subiektywnych przeprowadzono testy odsłuchowe, zgodnie z metodą przedstawioną w pracy. Końcowym efektem było porównanie wyników testów odsluchowych z wynikami otrzymanymi z modelu psychoakustycznego i pomiarów parametrów elektrycznych.
EN
The paper presets tests of sound quality of six acousitic amplifiers: one transistor amplifier (the standard one) and five vacuum-tube amplifiers. A series of subjective and objective trials was performed. During the objective tests, basic electric parameters of the amplifier were verified and a computerised psychoacoustic model was used. The subjective tests encompassed audio monitoring, according to the method presented herein. Finally, the results of audio monitoring tests ans the results obtained from the acoustic model and electric parameters were compared.
14
Content available remote Multiple dichotomies in timbre research
EN
In this paper an overview of aspects, terminology and literature on contemporary research regarding timbre is presented. Timbre is a multidimensional entity, and research traces its multifaceted nature. The paper handles this structural complexity using a domain-task-results paradigm. Several domains of application are examined and various aspects of timbre questioning are outlined, although consideration of aspects in music and its contextual applications are postponed for a following detailed report for reasons of presentation compactness and extent. A self-evident differentiation of research categorization stems from the type of consideration of timbre as a perceptual attribute or as a manifestation of physical (either generative or modified after transmission) phenomena and processes. As more "axes" of differentiation also emerge, this work attempts to highlight issues that rise and propose possible research directions.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.