Optimization of the Sound Source Position for Shaping Acoustically-Structurally Coupled Cavities

2001 ◽  
Author(s):  
Arzu Gonenc Sorguc ◽  
Ichiro Hagiwara ◽  
Qinzhong Shi ◽  
Haldun Akagunduz
Keyword(s):  
Sound Source ◽  
Sequential Quadratic Programming ◽  
Normal Modes ◽  
Sound Field ◽  
Source Strength ◽  
Source Position ◽  
Sound Sources ◽  
Coupled Cavities ◽  
Structural Loading ◽  
Initial Starting

Abstract In this study, sound field inside acoustically-structurally coupled rectangular cavity excited by structural loading and sound sources is shaped by optimizing the position of the sound source. In the optimization, Most Probable Optimal Design (MPOD) based on Holographic Neural Network is employed and the results are compared with Sequential Quadratic Programming (SQP). It is shown that source position, rather than source strength, is more effective in acoustically controlled modes. The nodal positions for in-vacuo acoustical normal modes are good candidates for initial starting points.

scholarly journals Application of Short Time Fourier Transform and Wavelet Transform for Sound Source Localization Using Single Moving Microphone in Machine Condition Monitoring

2016 ◽  
Vol 1 (1) ◽  
Author(s):  
Meifal Rusli
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Sound Source ◽  
Low Frequency ◽  
Peak Position ◽  
Source Position ◽  
Short Time Fourier Transform ◽  
Sound Sources ◽  
Time Frequency ◽  
Short Time

<p class="TTPParagraphothers"><em>The paper discusses means to predict sound source position emitted by fault machine components based on a single microphone moving in a linear track with constant speed.</em> The position of sound source that consists of some frequency spectrum is detected by time-frequency distribution of the sound signal through Short Time Fourier Transform (STFT) and Continues Wavelet Transform (CWT). <em>As the amplitude of sound pressure increases when the microphone moves closer, the source position and frequency are predicted from the peaks of time-frequency contour map</em><em>. </em>Firstly, numerical simulation is conducted using two sound sources that generate four different frequencies of sound. The second case is experimental analysis using rotating machine being monitored with unbalanced, misalignment and bearing defect. The result shows that application of both STFT and CWT are able to detect multiple sound sources position with multiple frequency peaks caused by machine fault. The STFT can indicate the frequency very clearly, but not for the peak position. On the other hand, the CWT is able to predict the position of sound at low frequency very clearly. However, it is failed to detect the exact frequency because of overlapping.</p>

Study of Spherical Near-Field Acoustic Holography with Rigid Spherical Microphone Array

2013 ◽  
Vol 546 ◽  
pp. 156-163
Author(s):  
Xin Guo Qiu ◽  
Ming Zong Li ◽  
Huan Cai Lu ◽  
Wei Jiang
Keyword(s):  
Sound Source ◽  
Microphone Array ◽  
Near Field ◽  
Sound Field ◽  
Acoustic Holography ◽  
Real Situation ◽  
Helmholtz Equations ◽  
Sound Sources ◽  
Array Configuration ◽  
Sphere Radius

The aim of this paper is to investigate the impacts of various parameters of rigid spherical microphone array in detecting and locating interior sound source. Helmholtz Equations are adopted to express the sound field produced by the incident field and scattered field. The gradient of the pressure is zero at the surface for the sphere is rigid. Both the incident and scattered coefficient could be obtained by solving the Helmholtz Equation using the boundary condition. Then the interior sound field could be detected and located on with the methodology of spherical near-field acoustic holography (SNAH). This study is developed in two aspects，one is configuring the microphone in various distribution in the same sphere radius, and the other one is changing the radius of sphere array. Numerical simulations are carried out to determine the optimum microphone array configuration and structure parameters. One, two, and three sound sources are arranged respectively in different displacement to the sphere center and in different angle direction to simulate the real situation. During the experiments, Omni-directional speakers and beeps are adopted as sound sources. The result shows that the method to detect and locate sound source in interior sound field is valid.

Reproduction of Phantom Sources Improves with Separation of Direct and Reflected Sounds

2015 ◽  
Vol 40 (4) ◽  
pp. 575-584
Author(s):  
Piotr Kleczkowski ◽  
Aleksandra Król ◽  
Paweł Małecki
Keyword(s):  
Sound Source ◽  
Sound Field ◽  
Angular Separation ◽  
Impulse Responses ◽  
Sound Sources ◽  
Perceptual Effect ◽  
Multichannel Systems ◽  
Virtual Acoustics

AbstractIn virtual acoustics or artificial reverberation, impulse responses can be split so that direct and reflected components of the sound field are reproduced via separate loudspeakers. The authors had investigated the perceptual effect of angular separation of those components in commonly used 5.0 and 7.0 multichannel systems, with one and three sound sources respectively (Kleczkowski et al., 2015, J. Audio Eng. Soc. 63, 428-443). In that work, each of the front channels of the 7.0 system was fed with only one sound source. In this work a similar experiment is reported, but with phantom sound sources between the front loud- speakers. The perceptual advantage of separation was found to be more consistent than in the condition of discrete sound sources. The results were analysed both for pooled listeners and in three groups, according to experience. The advantage of separation was the highest in the group of experienced listeners.

scholarly journals Effect of the Sound Source Position Error on Distribution Characteristics of Underwater Shock Wave Bunching Sound Field

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Xiaolong Liu ◽  
Hongbing Li ◽  
Ning Li ◽  
Kaizhuo Lei
Keyword(s):  
Shock Wave ◽  
Sound Source ◽  
Sound Field ◽  
Position Error ◽  
Distribution Characteristics ◽  
Source Position ◽  
Discharge Electrode ◽  
Finite Element Software ◽  
Position Errors ◽  
Effective Discharge

Curved reflection bunching technique of underwater plasma sound source (UPSS) uses the geometric characteristics of the curved reflector to reflect and bunching intense sound shock wave, so the center position error of the sound source is one of the important factors affecting the bunching performance of the shock wave. In this paper, the cause of the sound source position error is analyzed in detail, and nonlinear finite element software ANSYS/LS-DYNA (dynamic analysis software developed by LSTC) is used to establish the model of the shock wave bunching sound field. Through numerical simulations, the shock wave bunching sound field distribution characteristics under the influence of different position errors are comprehensively simulated, and the bunching performance of the shock wave and its influence law are deeply analyzed according to the simulation results. It provides guidance for reasonably controlling the machining error and installation error of the reflector and discharge electrode, estimating the effective discharge times of the discharge electrode, and formulating the design process.

scholarly journals Application of Short Time Fourier Transform and Wavelet Transform for Sound Source Localization Using Single Moving Microphone in Machine Condition Monitoring

2016 ◽  
Vol 1 ◽  
Author(s):  
Meifal Rusli
Keyword(s):  
Fourier Transform ◽  
Wavelet Transform ◽  
Sound Source ◽  
Low Frequency ◽  
Peak Position ◽  
Source Position ◽  
Short Time Fourier Transform ◽  
Sound Sources ◽  
Time Frequency ◽  
Short Time

<p class="TTPParagraphothers"><em>The paper discusses means to predict sound source position emitted by fault machine components based on a single microphone moving in a linear track with constant speed.</em> The position of sound source that consists of some frequency spectrum is detected by time-frequency distribution of the sound signal through Short Time Fourier Transform (STFT) and Continues Wavelet Transform (CWT). <em>As the amplitude of sound pressure increases when the microphone moves closer, the source position and frequency are predicted from the peaks of time-frequency contour map</em><em>. </em>Firstly, numerical simulation is conducted using two sound sources that generate four different frequencies of sound. The second case is experimental analysis using rotating machine being monitored with unbalanced, misalignment and bearing defect. The result shows that application of both STFT and CWT are able to detect multiple sound sources position with multiple frequency peaks caused by machine fault. The STFT can indicate the frequency very clearly, but not for the peak position. On the other hand, the CWT is able to predict the position of sound at low frequency very clearly. However, it is failed to detect the exact frequency because of overlapping.</p>

scholarly journals ACOUSTIC CHARACTERISTICS OF PULSED SOUND SOURCES OF VARIOUS TYPES/ĮVAIRIŲ TIPŲ IMPULSINIŲ GARSO ŠALTINIŲ AKUSTINĖS CHARAKTERISTIKOS

1998 ◽  
Vol 4 (4) ◽  
pp. 311-315 ◽  
Author(s):  
Vytautas Stauskis ◽  
Vytautas Kunigėlis
Keyword(s):  
Pulse Duration ◽  
Sound Source ◽  
Short Pulse ◽  
Sound Field ◽  
Correct Selection ◽  
Sound Sources ◽  
Major Drawback ◽  
Maximum Width ◽  
Acoustic Characteristics ◽  
Sound Energy

The paper examines the acoustic characteristics of explosion-type pulsed sound sources of four types. These include a Calibre 8 sound gun, a start gun, a Calibre 16 hunting gun, and a toy gun. The latter was included both because of its short pulse duration and for comparison purposes. Correct selection of a source is very important because it largely determines the results of acoustic measurements. Certain requirements are set for a sound source. In order to concentrate as much energy as possible at the given moment, the signal bandwidth-duration product must be as large as possible. The range frequencies to be excited depend on the pulse duration. The latter also determines whether interference phenomena will occur in the room and whether individual reflections will merge. The experiments were conducted in a room of 12 m2. The distance between the microphone and the pulsed sound source was 1 m. The structure of reflections depends on the pulse by means of which the sound field is excited. The smallest number of reflections is generated by a sound source. During a 20 ms experiment, the amplitudes of these reflections almost coincided with the direct sound amplitude. A sound gun emits more sound energy than other pulses. When the sound field is excited by means of a start gun and a hunting gun, the reflection structure, by amplitude, is very different from that produced by a sound gun. A dense reflection structure is formed by a toy gun but it emits less energy. The structure of reflections generated by a hunting gun is acceptable but its shots are very unstable, which is a major drawback in an experiment. The shots from a sound gun differ only by about 0.1% among themselves by amplitude, ie they are sufficiently stable. Among the four sound sources, the best reflection structure is produced by a sound gun. A sound gun is characterised both by the longest pulse duration (about 0.55 ms) and the highest levels of energy emitted. The pulse duration of the rest three guns is almost equal and is about 0.15 ms, ie is 3.6 times shorter than that of a sound gun. The forms of signals emitted by these sound sources are also very different. The spectrum of a sound source was established on Fourier transformation basis. The spectrum is largely dependent on the type of a gun by means of which the sound field is excited. The maximum width of the spectrum generated by a sound gun occupies almost two octaves, from 500 to 2000 Hz, and the radiation in this range is quite uniform. The spectra of a start gun and a hunting gun are similar but these guns emit less sound energy than a sound gun. The structure of reflections generated by them is also quite different. A toy gun radiates energy in a less narrower band, the width of which occupies about a half of octave, with a maximum at 2000 Hz. This is not very good because too small quantities of low- and medium-frequency sound energy are radiated.

scholarly journals Influence estimation of the inclination angle of the top of the noise protection barrier on its efficiency

2021 ◽  
Vol 1 (1(57)) ◽  
pp. 12-16
Author(s):  
Vitaly Zaets
Keyword(s):  
Inclination Angle ◽  
Sound Source ◽  
Sound Field ◽  
Wide Frequency Range ◽  
Sound Insulation ◽  
Frequency Range ◽  
Noise Barriers ◽  
Sound Sources ◽  
Sound Levels ◽  
Number Of Publications

The object of research is the sound field from linear sound sources around a rounded noise barrier of the same height and different angles of inclination of the top part of the barrier. It is known that the effectiveness of noise protection barriers depends primarily on the geometric dimensions of the barrier and the relative position of the sound source, barrier and area of noise protection. A large number of publications have been devoted to the study of the influence of these factors and some others, such as the influence of the earth's surface, sound absorption, sound insulation of the barrier. However, these works did not study the effect of the angle of the top part of the barrier on the change in the barrier efficiency. In this paper, the reduction of sound levels from linear sound sources around noise barriers with different inclination angle of the top part of the barrier is investigated. Rounded barriers of the same height with different radii are considered, which made it possible to simulate barriers in which the top part of the barrier has a different inclination angle. An effectiveness of such barriers for various locations of the sound source, which could also affect the establishment of a pattern of changes in the effectiveness of barriers, is also considered. In addition, the results were analyzed over a wide frequency range. The calculation of the field around such a barrier was carried out using computer simulation using the finite element method. This method allows to easily change the geometric parameters of the barrier and the position of the sound source. The barriers were considered acoustically hard. Thus, an influence of the inclination angle of the top part of the barrier on the sound field around the barrier from various locations of sound sources in a wide frequency range is analysed. The results must be taken into account when designing noise barriers to reduce noise levels from traffic flows

scholarly journals Binaural (pre)processing for contralateral sound field attenuation and improved speech-in-noise recognition

2021 ◽  
Author(s):  
Enrique A. Lopez-Poveda ◽  
Almudena Eustaquio-Martín ◽  
Fernando Martín San Victoriano
Keyword(s):  
Sound Source ◽  
Transfer Functions ◽  
Signal To Noise Ratio ◽  
Free Field ◽  
Sound Field ◽  
Directivity Pattern ◽  
Sound Sources ◽  
Speech In Noise ◽  
Speech Reception ◽  
Speech Reception Thresholds

ABSTRACTUnderstanding speech presented in competition with other sound sources can be challenging. Here, we reason that this task can be facilitated by improving the signal-to-noise ratio (SNR) in either of the two ears and that in free-field listening scenarios, this can be achieved by attenuating contralateral sounds. We present a binaural (pre)processing algorithm that improves the SNR in the ear ipsilateral to the target sound source by linear subtraction of the weighted contralateral stimulus. Although the weight is regarded as a free parameter, we justify setting it equal to the ratio of ipsilateral to contralateral head-related transfer functions averaged over an appropriate azimuth range. The algorithm is implemented in the frequency domain and evaluated technically and experimentally for normal-hearing listeners in simulated free-field conditions. Results show that (1) it can substantially improve the SNR (up to 20 dB) and the short-term intelligibility metric in the ear ipsilateral to the target source, particularly for speech-like maskers; (2) it can improve speech reception thresholds for sentences in competition with speech-shaped noise by up to 8.5 dB in bilateral listening and 10.0 dB in unilateral listening; (3) it hardly affects sound-source localization; and (4) the improvements, and the algorithm’s directivity pattern depend on the weights. The algorithm accounts qualitatively for binaural unmasking for speech in competition with multiple maskers and for multiple target-masker spatial arrangements, an unexpected property that can inspire binaural intelligibility models.

scholarly journals Research of Space Positioning Method Based on Sound Field HBT Interference

2018 ◽  
Vol 232 ◽  
pp. 04028
Author(s):  
Jing Zou ◽  
Lei Nie ◽  
Mengran Liu ◽  
Chuankai Jiang
Keyword(s):  
Source Localization ◽  
Sound Source ◽  
Target Location ◽  
Sound Propagation ◽  
Sound Field ◽  
Long Distance ◽  
Sound Sources ◽  
Positioning Method ◽  
New Ideas ◽  
Propagation Media

Based on Hanbury Brown-Twiss (HBT) interference in the sound field, a space positioning method is presented to realize the long-distance and high-precision positioning of sound sources in media. Firstly, theoretical model of HBT interference positioning is established. Location of the sound source can be acquired by analyzing the correlation function of the output signals. Then, sound source localization under different signal-to-noise ratios (SNR) shows that by this method, the sound source can be accurately found with six sensors (two arrays) even the SNR is low to 0.04. Positioning experiment in air is carried out, and the experimental results show that the sound source can be accurately located at 42 meters, and the positioning error is low to 0.1 meters. Thus the validity and accuracy of the HBT interference space location principle is demonstrated. It provides new ideas for the research of long-range target location in sound propagation media (air, water, etc.).

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