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Wyświetlanie 1-15 z 126
Tytuł:
The Characteristic of Sound Reflections from Curved Reflective Panels
Autorzy:
Szeląg, A.
Kamisiński, T.
Lewińska, M.
Rubacha, J.
Pilch, A.
Powiązania:
https://bibliotekanauki.pl/articles/177712.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound reflection
reflective panels
sound scattering
Opis:
The paper presents the verification of a solution to the narrow sound frequency range problem of flat reflective panels. The analytical, numerical and experimental studies concerned flat panels, panels with curved edges and also semicircular elements. There were compared the characteristics of sound reflected from the studied elements in order to verify which panel will provide effective sound reflection and also scattering in the required band of higher frequencies, i.e. above the upper limit frequency. Based on the conducted analyzes, it was found that among some presented solutions to narrow sound frequency range problem, the array composed of panels with curved edges is the most preferred one. Nevertheless, its reflection characteristic does not meet all of the requirements, therefore, it is necessary to search for another solution of canopy which is effective over a wide frequency range.
Źródło:
Archives of Acoustics; 2014, 39, 4; 549-558
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sound Scattering by an Elastic Spherical Shell and its Cancellation using a Multi-pole Approach
Autorzy:
Avital, E. J.
Bholah, N. D.
Giovanelli, G. C.
Miloh, T.
Powiązania:
https://bibliotekanauki.pl/articles/177764.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound scattering
structural dynamics
sound cancellation
Opis:
The scattering and transmission of sound by an elastic spherical shell is considered when it is subject to an incoming monochromatic planar wave. It is aimed to cancel the sound scattering using combinations of multi-pole sources located at the centre of a shell filled with compressible fluid. Assuming linear acoustics and structural dynamics, exact solutions are derived for total elimination of the sound scattering for three cases: a free-space, near a hard ground or near a free-surface, where in the last two cases it is assumed that the incoming wave propagates normal to the interface to maximize sound reflection back unto the source of the incoming wave. An elastic spherical shell of 1 m radius embedded in water and filled with air or oil is analysed to show the dominance of low-mode numbers for frequencies of less than 10 kHz and thus demonstrate the ability of this approach to damp acoustic scattering by means of low-order multi-poles inside the shell. Contour and mode distribution plots are also given and analysed.
Źródło:
Archives of Acoustics; 2017, 42, 4; 697-705
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Revised Sound Energy Theory Based on a New Formula for the Reverberation Radius in Rooms with Non-Diffuse Sound Field
Autorzy:
Arau-Puchades, H.
Berardi, U.
Powiązania:
https://bibliotekanauki.pl/articles/177958.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
reverberation radius
critical distance
non-diffuse sound field
sound energy
revised sound decay theory
Opis:
This paper discusses the concept of the reverberation radius, also known as critical distance, in rooms with non-uniformly distributed sound absorption. The reverberation radius is the distance from a sound source at which the direct sound level equals the reflected sound level. The currently used formulas to calculate the reverberation radius have been derived by the classic theories of Sabine or Eyring. However, these theories are only valid in perfectly diffused sound fields; thus, only when the energy density is constant throughout a room. Nevertheless, the generally used formulas for the reverberation radius have been used in any circumstance. Starting from theories for determining the reverberation time in non-diffuse sound fields, this paper firstly proposes a new formula to calculate the reverberation radius in rooms with non-uniformly distributed sound absorption. Then, a comparison between the classic formulas and the new one is performed in some rectangular rooms with non-uniformly distributed sound absorption. Finally, this paper introduces a new interpretation of the reverberation radius in non-diffuse sound fields. According to this interpretation, the time corresponding to the sound to travel a reverberation radius should be assumed as the lower limit of integration of the diffuse sound energy.
Źródło:
Archives of Acoustics; 2015, 40, 1; 33-40
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Automatic Synthesis of Musical Phrases from Multi-Pitch Samples
Autorzy:
Pluta, M.
Spalek, L. J.
Delekta, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/177577.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound synthesis
synthesis methods
sampling
Concatenative Sound Synthesis
Opis:
Sound synthesizers are a natural element of a musician’s toolset. In music arrangement, samplers can often produce satisfactory results, but it requires a combination of manual and automatic methods that may be arduous at times. Concatenative Sound Synthesis reproduces many of natural performance- and expression-related nuances but at a cost of high demand for processing power. Here, another method of musical phrase synthesis aimed at music arrangement is presented that addresses these and other related issues. Contrary to common practice, we propose to record and utilize sound samples containing not one, but short sequences of pitches. In effect, natural pitch transitions are preserved and phrases appear to be much smoother, despite using very limited set of performance rules. The proof-of-concept implementation of the proposed method is discussed in detail along with attempts at optimizing the final sound effects, based on auditory tests. The limitations and future applications of the synthesizer are also discussed.
Źródło:
Archives of Acoustics; 2017, 42, 2; 235-247
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Acoustic Flow Analysis Inside a Section of an Acoustic Waveguide
Autorzy:
Weyna, S.
Mickiewicz, W.
Pyła, M.
Jabłoński, M.
Powiązania:
https://bibliotekanauki.pl/articles/178109.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound intensity
laser anemometry
acoustics flow
sound visualization
Opis:
Noise propagation within ducts is of practical concern in many areas of industrial processes where a fluid has to be transported in piping systems. The paper presents experimental data and visualization of flow in the vicinity of an abrupt change in cross-section of a circular duct and on obstacles inside where the acoustic wave generates nonlinear separated flow and vortex fields. For noise produced by flow wave of low Mach number, laminar and turbulent flows are studied us- ing experimental sound intensity (SI) and laser particle image velocimetry (PIV) technique adopted to acoustics (A-PIV). The emphasis is put on the development and application of these methods for better understanding of noise generation inside the acoustic ducts with different cross-sections. The intensity distribution inside duct is produced by the action of the sum of modal pressures on the sum of modal particle velocities. However, acoustic field is extremely complicated because pressures in non-propagating (cut-off) modes cooperate with particle velocities in propagating modes, and vice versa. The discrete frequency sound is strongly influenced by the transmission of higher order modes in the duct. By under- standing the mechanism of energy in the sound channels and pipes we can find the best solution to noise abatement technology. In the paper, numerous methods of visualization illustrate the vortex flow as an acoustic velocity or sound intensity stream which can be presented graphically. Diffraction and scattering phenomena occurring inside and around the open-end of the acoustic duct are shown.
Źródło:
Archives of Acoustics; 2013, 38, 2; 211-216
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A System for Acoustic Field Measurement Employing Cartesian Robot
Autorzy:
Szczodrak, M.
Kurowski, A.
Kotus, J.
Czyżewski, A.
Kostek, B.
Powiązania:
https://bibliotekanauki.pl/articles/221435.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cartesian robot
sound intensity
sound field
anechoic chamber
Opis:
A system setup for measurements of acoustic field, together with the results of 3D visualisations of acoustic energy flow are presented in the paper. Spatial sampling of the field is performed by a Cartesian robot. Automatization of the measurement process is achieved with the use of a specialized control system. The method is based on measuring the sound pressure (scalar) and particle velocity(vector) quantities. The aim of the system is to collect data with a high precision and repeatability. The system is employed for measurements of acoustic energy flow in the proximity of an artificial head in an anechoic chamber. In the measurement setup an algorithm for generation of the probe movement path is included. The algorithm finds the optimum path of the robot movement, taking into account a given 3D object shape present in the measurement space. The results are presented for two cases, first without any obstacle and the other - with an artificial head in the sound field.
Źródło:
Metrology and Measurement Systems; 2016, 23, 3; 333-343
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Urethane Foam Cushioning on Structure-Borne Sound Transfer by a Slab with Panel Flooring
Autorzy:
Mu, R.
Toyoda, M.
Takahashi, D.
Powiązania:
https://bibliotekanauki.pl/articles/176817.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
urethane foam
direct pasted flooring
floor impact sound
sound pressure level
sound insulation performance
Opis:
Urethane foam mattresses are commonly used as cushioning when placing panel flooring on the floor slab of a building. Urethane foam consists of elastic fibres with pores. Both elements can affect the performance of the insulation against impact sounds. However, these effects have not yet been detailed, and they may change if the material properties or constitution of the fibres and pores in the cushioning change. In this paper, we propose an analytical model for use in evaluating the performance of insulation against floor impact sound. This model was used to examine the contribution of the pores versus the elastic fibres to wave transmissions from the flooring surface to the slab. The results reveal that the constitution of the foam (either open or closed cells of pores) and the thickness and hardness of the cushion layer strongly affect the sound insulation performance of the floor.
Źródło:
Archives of Acoustics; 2016, 41, 1; 99-106
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sound Radiation by a Cylindrical Open Cavity with a Surface Source at the Bottom
Autorzy:
Szemela, K.
Powiązania:
https://bibliotekanauki.pl/articles/176682.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
open cylindrical cavity
sound pressure
sound power
continuity conditions
Opis:
The rigorous solution describing the sound radiation by an arbitrary surface source located at the bottom of a cylindrical open cavity embedded in a flat baffle has been obtained. The open cavities of different shapes can be found in some architectural structures as well as are components of sensors, musical instruments and vehicles. The presented formulas have been expressed in the form of Infinite sums. To use them, the infinite sums have to be truncated to the finite number of terms. Therefore, in practice, the results obtain based on the proposed solution are not exact and their accuracy is determined by the truncation error. The use of presented formulas is an alternative method for the finite element method (FEM). However, taking into account that the calculation efficiency of FEM rapidly decrease when a volume of considered region increases, the obtained in this study solution can be more useful in some practical cases. The approximated formula of a high computational efficiency has been presented for the sound pressure in the far field. The sound radiation has been analyzed for a rectangular piston as a sound source. The influence of cavity depth ratio on the radiation efficiency has been investigated. The cases for which the cavity radiation efficiency can be approximately calculated from the formula valid for a baffled sound source have been determined.
Źródło:
Archives of Acoustics; 2018, 43, 1; 49-60
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Comprehensive Research of the Road Acoustic Screen with Absorbing and Diffusing Surface
Autorzy:
Kamisiński, T.
Kinasz, R.
Szeląg, A.
Rubacha, J.
Pilch, A.
Flach, A.
Baruch, K.
Powiązania:
https://bibliotekanauki.pl/articles/177952.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustics
mechanical strength
environmental actions
sound reflection
sound diffusion
Opis:
The paper presents the new solution to a road acoustic screen consisting of elements which are highly diffusing and simultaneously resistant to weathering, but also characterised by a sound absorption. There is described the comprehensive research of such the road acoustic screen with absorbing and diffusing surface. The study includes screen’s resistance to wind load and snow removal, impact tests and measurements of some acoustic parameters.
Źródło:
Archives of Acoustics; 2015, 40, 1; 137-144
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Sound Insulation of Sandwich Partition Panels by Means of Artificial Neural Networks
Autorzy:
Garg, N.
Dhruw, S.
Gandhi, L.
Powiązania:
https://bibliotekanauki.pl/articles/176461.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
weighted sound reduction index
Rw
Sound Transmission Class
STC
Opis:
The paper presents the application of Artificial Neural Networks (ANN) in predicting sound insulation through multi-layered sandwich gypsum partition panels. The objective of the work is to develop an Artificial Neural Network (ANN) model to estimate the Rw and STC value of sandwich gypsum constructions. The experimental results reported by National Research Council, Canada for Gypsum board walls (Halliwell et al., 1998) were utilized to develop the model. A multilayer feed-forward approach comprising of 13 input parameters was developed for predicting the Rw and STC value of sandwich gypsum constructions. The Levenberg-Marquardt optimization technique has been used to update the weights in back-propagation algorithm. The presented approach could be very useful for design and optimization of acoustic performance of new sandwich partition panels providing higher sound insulation. The developed ANN model shows a prediction error of ± 3 dB or points with a confidence level higher than 95%.
Źródło:
Archives of Acoustics; 2017, 42, 4; 643-651
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Plate Discretization on Accuracy of the Sound Radiation Efficiency Measurements
Autorzy:
Kolber, K.
Snakowska, A.
Kozupa, M.
Powiązania:
https://bibliotekanauki.pl/articles/177333.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound radiation efficiency
sound radiation from plates
discrete calculation method
Opis:
This paper deals with the problem of the effect of discretization level and certain other parameters characterizing the measurement setup on accuracy of the process of determination of the sound radiation efficiency by means of the Discrete Calculation Method (DCM) described by Hashimoto (2001). The idea behind DCM consists in virtual division of an examined sound radiating structure into rectangular elements each of which is further assumed to contribute to the total radiation effect in the same way as a rigid circular piston having the surface area equal to this of the corresponding virtual element and vibrating in an infinite rigid baffle. The advantage of the method over conventional sound radiation efficiency measurement techniques consists in the fact that instead of acoustic pressure values, source (plate) vibration velocity amplitude values are measured in a selected number of regularly distributed points. In many cases, this allows to determine the sound radiation efficiency with sufficient accuracy, especially for the low frequency regime. The key part of the paper is an analysis of the effect of discretization level (i.e. the choice of the number of points at which vibration amplitude measurements are to be taken with the use of accelerometers) on results obtained with the use of the method and their accuracy. The problem of determining an optimum level of discretization for given excitation frequency range is a very important issue as the labor intensity (time-consuming aspect) of the method is one of its main flaws. As far as the technical aspect of the method is concerned, two different geometrical configurations of the measurement setup were tested.
Źródło:
Archives of Acoustics; 2014, 39, 4; 511-518
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-Objective Optimization of Acoustical Properties of PU-Bamboo-Chips Foam Composites
Autorzy:
Jiang, Y.
Chen, S.
Wang, D.
Chen, J.
Powiązania:
https://bibliotekanauki.pl/articles/177709.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
vehicle sound package
sound absorption coefficient
transmission loss
Taguchi method
Opis:
In this study, an effective optimization approach was proposed to improve acoustical behaviors of PU foams. The important parameters of PU foams: content of water, silicone oil and catalyst A1 were chosen and their effects on sound absorption coefficient and transmission loss of PU foams were studied by using Taguchi methods. In addition, bamboo chips were incorporated into PU foams as fillers to improve the acoustical properties of PU foams. Four controlled factors: the content of water, silicone oil, catalyst A1 and bamboo chips with three levels for each factor were chosen and Taguchi method based on orthogonal array L9 (34) was employed to conduct the experiments. Based on the results of Taguchi’s orthogonal array L9 (34), signal-to noise (S/N) analysis was used and developed to determine an optimal formulation of PU-bamboo-chips foam composites.
Źródło:
Archives of Acoustics; 2017, 42, 4; 707-714
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Estimation of Asymmetry in Head Related Transfer Functions
Autorzy:
Jasiński, Maciej
Żera, Jan
Powiązania:
https://bibliotekanauki.pl/articles/2055229.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustics
sound processing
virtual reality
spatial sound
Head Related Transfer Functions
Opis:
The individual Head-Related Transfer Functions (HRTFs) typically show large left-right ear differences. This work evaluates HRTF left-right differences by means of the rms measure called the Root Mean Square Difference (RMSD). The RMSD was calculated for HRTFs measured with the participation of a group of 15 subjects in our laboratory, for the HRTFs taken from the LISTEN database and for the acoustic manikin. The results showed that the RMSD varies in relation to the frequency and as expected is small for more symmetrical HRTFs at low frequencies (0.3÷1 kHz). For higher frequency bands (1÷5 kHz and above 5 kHz), the left-right differences are higher as an effect of the complex filtering caused by anatomical shape of the head and the pinnae. Results obtained for the subjects and for data taken from the LISTEN database were similar, whereas different for the acoustic manikin. This means that measurements with the use of the manikin cannot be considered as perfect average representation of the results obtained or people. The method and results of this study may be useful in assessing the symmetry of the HRTFs, and further analysis and improvement of how to considered the HRTFs individualization and personalization algorithms.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 2; 193--200
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Method of Testing of Sound Absorption Properties of Materials Intended for Ultrasonic Noise Protection
Autorzy:
Pleban, D.
Powiązania:
https://bibliotekanauki.pl/articles/177443.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ultrasonic noise
sound absorption coefficient
tone burst technique
sound absorbing material
Opis:
Efficient ultrasonic noise reduction by using enclosures requires the knowledge of absorbing properties of materials in the frequency range above 4 kHz. However, standardized methods enable determination of absorption coefficients of materials in the frequency range up to 4 kHz. For this reason, it is proposed to carry out measurements of the sound absorption properties of materials in the free field by means of a tone-burst technique in the frequency range from 4 kHz to 40 kHz at angles of incidence varying from 0° to 60°. The absorption coefficient of a material is calculated from the reflection coefficient obtained by reflecting a tone-burst from both a perfectly reflecting panel and a combination of this panel and the sample of the tested material. The tests results show that mineral wool and polyurethane open-cell foam possess very good absorbing properties in this frequency range.
Źródło:
Archives of Acoustics; 2013, 38, 2; 191-195
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Definition and Measure of the Sound Quality of the Machine
Autorzy:
Pleban, D.
Powiązania:
https://bibliotekanauki.pl/articles/176874.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound quality
machine
noise
Opis:
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.
Źródło:
Archives of Acoustics; 2014, 39, 1; 17-23
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 126

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