Position Of Sound Source Research Articles

Sound insulation of partially open windows - alternative laboratory measurement methods

Sound insulation with partially open windows has had growing attention in recent years. In Denmark, this is primarily caused by the Danish Environmental Protection Agency's guideline from 2007 "Noise from roads", which introduces noise limits with open windows (opening area of 0.35 m2) for situations with a high traffic noise level. The sound insulation of traditional windows in open position have been measured in both the laboratory and external environment, and for certain setups too different results have been observed. To investigate the reasons behind the discrepancies, the traditionally reverberant source room of laboratory measurements was modified to a semi-anechoic room to remove reflections from unwanted reflections from room surfaces and to imitate the external environment during field measurements. Four different window types were tested as part of the research projects "Optimized measurement method for sound reduction of partially open windows part 1 and 2" (MetÅV and MetÅV2) in collaboration with four Danish window manufacturers. The primary focus of the project is to explore alternative laboratory methods to the traditional diffuse field method by studying reference cases from field measurements and taking into consideration different sound source positions and window geometry. This paper describes the results so far.

Characterization of façade sound insulation by impulse response measurements for various source position formats: a case study

The sound insulation of a building's façade is important for estimating the indoor levels in relation to the outdoor levels. The measurement of the sound insulation (i.e., outdoor-to-indoor level difference) is significantly affected by the methodology employed. In this study, an impulse response measurement methodology is incorporated, alleviating uncertainties associated with the measurement's chain. The effect of loudspeaker position on sound insulation is investigated with respect to three source position formats (horizontal, inclined, and linear), each consisting of three source positions. The appropriate length of the excitation signal is verified using the impulse-to-noise ratio (INR) indicator. Focusing on the outdoor-to-indoor level differences, corresponding to the energy captured in each external receiver (placed very close to windows) and across all the internal receivers per source position, significant differences were found. This indicates the impact of both the distance and angle of incidence between the outdoor receiver and the sound source position. In terms of the average outdoor-to-indoor level difference among the three source formats, the linear format shows slightly lower values compared to the horizontal and inclination source formats, which are similar to each other, but follows the main trend.

Effect of background noise and diffraction on localization of sound sources using distributed acoustic measurement equipment

This study is focused on the development of a system designed to pinpoint the positions of sound sources within a plane through the analysis of cross-correlated signals obtained from distributed microphones. Our investigation delved into assessing the impact of physical barriers and background noise on the accuracy of the proposed method for localizing sound sources. Prior research has demonstrated that measurements conducted within an anechoic chamber yield estimations accurate to within ±20 mm. When the signal-to-noise ratio of the target sound source is reduced by the background noise, the estimation is performed at the point of background noise generation. Furthermore, the introduction of physical barriers between the sound source and the microphones resulted in sound diffraction, thereby leading to estimation errors attributable to the varying lengths of diffraction paths. These findings underscore the importance of considering environmental factors in sound source localization endeavors. The estimation at Mic, where the sound-receiving level drops below -10 dB due to physical barriers, confirmed that the background noise source point is estimated as well as the background noise estimation error.

TSSL: Trusted Sound Source Localization

Despite significant advancements in the accuracy of sound source localization, the confidence and robustness of the results still require improvement. Conducting uncertainty estimation can effectively alleviate this problem, since it provides a measure of confidence in the sound source localization results. In this work, we propose a trusted sound source localization neural network which can generate the accurate localization results and reliable uncertainty estimations. In this approach, the subjective theory was employed for associating the Dirichlet distribution with the predictions obtained from the neural network, treating them as subjective opinions. This allows us to model the overall uncertainty by parameterizing the class probabilities of sound source position using a Dirichlet distribution. Moreover, the reliable evidence supporting for the robust and reliable sound source localization results can also be gathered by the proposed method. In sum, this approach enhances the robustness of the neural network when facing with the out-of-distribution samples. To comprehensively evaluate the proposed method in the aspect of accuracy and robustness, extensive experiments were conducted on both simulated and real-world datasets. The proposed method outperforms other competing methods in the performance of robustness and reliability.

Influence of spatial position of sound source on dual-frequency ultrasound-assisted preparation of magnesium alloy

In this work, a dual-frequency ultrasonic field was employed to improve the quality and mechanical properties of magnesium alloy ZW61 ingot. The effect of the spatial position of the sound source on the cavitation volume, microstructure size, and morphology was discussed in detail combined with numerical simulations and experiments. The mechanical properties were analyzed elaborately and the relationship between yield strength (YS), ultimate tensile strength (UTS), and average grain size (d) was established. The results showed that the dual-frequency ultrasonic field (DUF) had a larger cavitation range and superior grain refinement ability than the single-frequency ultrasonic field (SUF) at the same energy consumption, with the grain refining from 578 μm (untreated) and 395–433 μm (SUF) to 55.2 μm. The grain refining effect of DUF weakened with increasing sound source spacing, with d increasing from 55.2 μm to 163 μm. The radiating angle had little effect on the grain size. Too shallow or too deep inserting depth of the ultrasonic rods could seriously weaken the grain refinement. In this case, 30 mm source spacing, 60° radiating angle, and 30 mm inserting depth were the optimal process parameter combinations, and the ingot strength was increased from YS of 83 MPa and UTS of 151 MPa to 138 MPa and 241 MPa, respectively. YS and d for all conditions conformed to the Hall-Petch relationship, with σ0 and k values of 71.3 MPa and 503.9 MPa μm−1/2. The relationship between UTS and d could be expressed as UTS = 126.7 + 907.0 d−1/2.

Improved method for drone sound event detection system aiming at the impact of background noise and angle deviation

Drones pose a hidden threat to public safety, and effective and accurate detection technology for the drone that exist in the environment is imminent, in which how to weaken the influence of target sound source localization deviation and strong background interference noise on the detection task is the key to improve the accuracy of drone sound event detection. In this paper, a method has been proposed to improve the accuracy of drone acoustic event detection, named as the linear shrinkage-subspace projection-power spectral density filter method (LSP). This method mainly including covariance matrix reconstruction, steering vector recalibration, and filter coefficient redesign method. Firstly, based on Minimum Variance Distortionless Response, the linear shrinkage method is used to suppress the interference and noise components in the signal plus interference covariance matrix, and the sample covariance matrix is reconstructed to eliminate background interference noise. Then, the correlation between the steering vector and the eigenvector is used to eliminate the angle correlation term, and the subspace projection method is combined to recalibrate the steering vector, so as to improve the ability of the beamforming method to resist the angle deviation and realize the correction of the target source positioning deviation. Next, a redesign method for wiener filter coefficients based on the estimated power spectral density is used to further weaken background interference noise. In order to verify the accuracy of the proposed method, a complete drone sound event detection system is constructed by combining the deep learning drone sound event detection classifier, and the evaluation is carried out according to different angular deviations and interference sound distances. In addition, a new evaluation criterion is proposed, named as the Machine-Human Extreme Hearing Distance Rate (MHDR), which analogizes the system's detection ability with the ear's auditory detection ability. The research results of this article indicate that the detection accuracy of the detection system shows satisfactory accuracy when the proposed method is applied to circular microphone array, that improved by 15.12 % compared to existing methods. The proposed method improves the detection accuracy of the drone acoustic event detection task under the influence of sound source position deviation and strong background speech interference, and provides a reference for the development of anti-drone technology.

Distributed extended Kalman filtering for acoustic simultaneous localization and environment mapping

The localization accuracy of Acoustic Simultaneous Localization and Mapping (ASLAM) often suffers from environmental noise and room reverberation. To solve this problem, an ASLAM method based on distributed extended Kalman filter is proposed. Specifically, the distance between the sound source and the robot is effectively estimated by the gating mechanism method in the case of unknown location of the sound source. Then, the Time Difference of Arrival (TDOA) between robots, the Direction of Arrival (DOA) and the distance between the sound source and the robot are presented as observation. Next, the robots' trajectories and the sound source's position are tracked by multiple extended Kalman filters. Finally, the ASLAM localization is completed by fusing the sound source and the robots' positioning information through average consensus algorithm, respectively. The proposed method can efficiently promote the ASLAM localization accuracy in complex acoustic environments. The experimental results verify the effectiveness of the proposed method.

A Controllable Response Power Beam Localization Method and System Implementation

Sound source localization technology has gradually become one of the main methods for fault source target localization in dangerous and difficult-to-discover applications. In order to locate the target fault sound source more intuitively, accurately and in real time in practical applications, an audio-visual positioning system is developed. A 64-channel microphone array is designed, which is evenly distributed in a circular shape, and has a video acquisition target at the same time. The system uses GCC-PHAT to estimate the relative time delay between the signal source arriving at two microphones, and then uses SRP-PHAT algorithm to obtain weighted sum beamforming. A spatial grid search strategy based on spherical coordinate spatial contraction method is proposed. When the output power is maximum, the direction corresponding to the beam is regarded as the sound source direction. Using the same sound source signal, the proposed positioning method is compared with the direct Newton iterative method and the Cartesian coordinate scanning SRP-based maximum method. The simulation results show that the Cartesian coordinate value and spherical coordinate value of the positioning algorithm in this article are closer to the real coordinates of the sound source position than the other two methods, and the positioning operation time is the shortest. In addition, in the actual corona discharge power source positioning experiment, the system can accurately locate the insulator pollution discharge point, which is consistent with the infrared detection and positioning results and has good robustness. Therefore, the system location method can provide a new choice for sound source location applications.

High-efficiency sound source localization using data-driven sparse sampling with validation using monopole laser sound source

This study proposes a framework that reduces the calculation cost of sound source localization with the Amiet model, using a data-driven sparse sampling method. This method accelerates the calculation of the steering vector used in conventional beamforming. An aeroacoustic wind tunnel test was conducted in a 2 × 2 m2 low-speed wind tunnel, and the proposed method was verified. During the test, a monopole laser sound source, which does not interfere with the flow, was used, and its acoustic signals were measured using a microphone array. Next, steering vectors were reconstructed by discovering dominant modes and optimized sampling points from the training data based on the Amiet model and the modified data-driven sparse sampling method. Finally, the sound-source positions when the steering vector of the proposed model was used were compared with the positions observed when the steering vector of which all the grid points were calculated was used. The error was less than 2 mm when 16 modes were used, and the calculation time was reduced to ∼1/33 of that of the previous Amiet model.

Effects of measured and simulated diffraction from a plate on sound source localization.

In daily life, natural or man-made structures influence sound propagation, causing reflections and diffraction with potential effects on auditory spatial perception. While the effect of isolated reflections on binaural localization has been investigated, consequences of edge diffraction on spatial perception have received less attention. Here, effects of edge diffraction on the horizontal localization of a sound source were assessed when a flat square plate occludes the direct sound or produces a reflection in an otherwise anechoic environment. Binaural recordings were obtained with an artificial head for discrete sound source positions along two horizontal trajectories in the vicinity of the plate, including conditions near the incident and reflection shadow boundary. In a listening test, the apparent source position was matched for conditions with and without the plate, resulting in azimuth offsets between the apparent and physical source of up to 12°. The perceived direction of occluded frontal sound sources was laterally shifted to the visible region near the edge of the plate. Geometrical-acoustics-based simulations with different methods to binaurally render diffracted sound paths were technically and perceptually compared to the measurements. The observed localization offset was reproduced with the acoustic simulations when diffraction was rendered considering the individual ear positions.

Three-dimensional sound source localization system based on fiber optic sensor array with an adaptive algorithm

Sound Source Localization (SSL) based on microphone arrays nowadays is widely used in the fields of machinery rattle localization, weapon navigation, and robot hearing. However, there is also a need for SSL in some special environments, such as long-distance gas pipelines where there is a risk of leakage. In these environments, arrays built with ordinary microphones can be a safety hazard, which can be compensated by the External Fabry-Perot interferometer (EFPI) fiber-optic sensor's advantages of being uncharged, inexpensive, and highly sensitive. To expand the application areas of microphone array-based SSL techniques, this paper using four EFPI fiber-optic sensors to constructs a 1 m × 1 m × 1 m sensor array, which is used for real-time localization of sound sources based on three-wavelength adaptive intensity demodulation methods and Time Difference Of Arrival (TDOA) localization techniques. An improved method is proposed for the three-wavelength adaptive intensity demodulation method to avoid the occurrence of signal flips. Finally, formulas are provided for this sensor array to quickly calculate the sound source position based on the arrival delay. Several experiments show that the system can achieve sound source localization over a wide range with an average error of less than 3 cm.

Spatial hearing training in virtual reality with simulated asymmetric hearing loss

Sound localization is essential to perceive the surrounding world and to interact with objects. This ability can be learned across time, and multisensory and motor cues play a crucial role in the learning process. A recent study demonstrated that when training localization skills, reaching to the sound source to determine its position reduced localization errors faster and to a greater extent as compared to just naming sources’ positions, despite the fact that in both tasks, participants received the same feedback about the correct position of sound sources in case of wrong response. However, it remains to establish which features have made reaching to sound more effective as compared to naming. In the present study, we introduced a further condition in which the hand is the effector providing the response, but without it reaching toward the space occupied by the target source: the pointing condition. We tested three groups of participants (naming, pointing, and reaching groups) each while performing a sound localization task in normal and altered listening situations (i.e. mild-moderate unilateral hearing loss) simulated through auditory virtual reality technology. The experiment comprised four blocks: during the first and the last block, participants were tested in normal listening condition, while during the second and the third in altered listening condition. We measured their performance, their subjective judgments (e.g. effort), and their head-related behavior (through kinematic tracking). First, people’s performance decreased when exposed to asymmetrical mild-moderate hearing impairment, more specifically on the ipsilateral side and for the pointing group. Second, we documented that all groups decreased their localization errors across altered listening blocks, but the extent of this reduction was higher for reaching and pointing as compared to the naming group. Crucially, the reaching group leads to a greater error reduction for the side where the listening alteration was applied. Furthermore, we documented that, across blocks, reaching and pointing groups increased the implementation of head motor behavior during the task (i.e., they increased approaching head movements toward the space of the sound) more than naming. Third, while performance in the unaltered blocks (first and last) was comparable, only the reaching group continued to exhibit a head behavior similar to those developed during the altered blocks (second and third), corroborating the previous observed relationship between the reaching to sounds task and head movements. In conclusion, this study further demonstrated the effectiveness of reaching to sounds as compared to pointing and naming in the learning processes. This effect could be related both to the process of implementing goal-directed motor actions and to the role of reaching actions in fostering the implementation of head-related motor strategies.

Method and practice of microphone array speech source localization based on sound propagation modeling

Abstract This paper realizes the speech source localization for microphone arrays based on the sound propagation model. According to the actual environment and location of the sound source, this paper divides the sound source into far-field source and near-field source and constructs the far-field sound model and near-field sound model applicable to the microphone array. The TDOA time-delayed localization algorithm is employed to locate the voice source of the microphone array by judging the sound far and near the field. In the localization test, this paper selects microphones to form an array according to the actual needs and preprocesses the sound signal data required for practice. The preprocessing data and sound source localization practice prove that the microphone array speech source localization algorithm used in this paper can effectively estimate the actual position of the sound source, and the absolute error between its estimated sound source position and the actual sound source position is only about 0.3m.

Analysis of the Influence of Sound Source Position and Electrode Placement on the Stimulation Pattern of the Cochlear Implant under Noise Conditions: Optimization of Auditory Perceptual Effects

Analysis of the Influence of Sound Source Position and Electrode Placement on the Stimulation Pattern of the Cochlear Implant under Noise Conditions: Optimization of Auditory Perceptual Effects

A study on the influence of reflective surfaces on sound source localization using distributed acoustic measurement equipment

This research aims to develop a system that will detect sound source localization in a broad area using cross-correlation functions for signals from distributed microphone arrays, which is difficult with conventional methods that use microphone arrays. For the localization of sound sources, four microphones were distributed in an anechoic room. Based on the result, the system was able to estimate the sound source position within a plus or minus 20 mm of accuracy. To verify the accuracy of the system, a reflective surface was set up in an anechoic room to confirm the effect of reflected and diffracted sound. No significant increase in error was observed when the reflective surface was behind the microphone as viewed from the sound source. However, the estimation error increased when diffracted sound was present.

Field measurement of ground effect for road traffic noises

In ASJ RTN-Model 2018, which was proposed by the Acoustical Society of Japan, a practical calculation method of the ground effect in A-weighted overall level for road traffic noise is specified by relatively simple formulae. The method is derived from the solution of the ground effect based on wave theory. By the practical calculation method, the attenuation level by the ground effect for a relatively long distance between the source and receivers tends to become larger on softer ground. Especially in the cases of lower sound source positions as specified in the ASJ RTN-Model 2018, the excess attenuation becomes large. To investigate the appropriate treatment of the ground condition in the case of road traffic noise propagation on soft ground, the authors have performed a field measurement of road traffic noise. The measurement results were compared with calculation results by both the ASJ RTN-Model 2018 and the theoretical solution based on the wave theory. From the comparison, the features of the propagation characteristics obtained by the ASJ RTN-Model 2018 were discussed.

Near-field modeling of the head-related transfer function by using the dummy head sound source

Various approaches based on direct measurement have been used to obtain the precise headrelated transfer function (HRTF). However, several problems persist, such as scattering of sound source and distance effect, which are related to the measurement configuration. In this work, the modified dummy head having two sound sources located at the ear positions is applied as the sound source reciprocally to overcome the trouble. By using the near-field acoustic holography, the sound sources located in the ear holes are reconstructed from the measured data in the near-field hologram. One can predict the acoustic transfer function between the ear holes and the field positions at any point using the recovered source information described in spherical harmonics. The obtained transfer function is valid for predicting the binaural response from any sound source position. This configuration is possible to measure the near-field response with the relatively small scattering effect because of the low Helmholtz number of microphones. The far-field reconstruction of HRTF is also possible with the near-field measurement data using acoustical holography. The proposed method is demonstrated with the modified B&K HATS system, in which the microphones in the ear holes are replaced by pipe sources connected to the loudspeaker.

Acoustic Characterization of Edzna: A Measurement Dataset

Acoustic characterizations of different locations are necessary to obtain relevant information on their behavior, particularly in the case of places that have not been fully understood or which purpose is still unknown since they are from cultures that no longer exist. Acoustic measurements were conducted in the archaeological zone of Edzna to obtain useful information to better understand the customs and practices of its past inhabitants. The information obtained from these acoustic measurements is presented in a dataset, which includes measurements taken at 32 points around the entire archaeological zone, with special attention given to the Main Plaza, the Great Acropolis, and the Little Acropolis. Two recording systems were used for this purpose: a microphone and a binaural head. As a result, a measurement database with the following characteristics was obtained: it comprises a total of 32 measurement points with 4 different sound source positions. In total, there are 297 files divided into separate folders. The sampling frequency used was 96 kHz, and the files are in mat format.

Fast estimation of distance between two hydrophones using ocean ambient noise in multi-ship scenarios

Accurately estimating the bearing of a target with two hydrophones requires knowing the precise distance between them. However, in practice, it is difficult to measure this distance accurately due to the influence of current. To solve this problem, we propose a method for extracting the time-domain Green’s function between two points in multi-ship scenarios and for extracting the time-domain waveform arrival structure between two hydrophones in real-time based on long samples of ship radiation noise cross-correlation. Using the cross-correlation function of the radiated noise from any ship located in the end-fire direction of the two hydrophones, we can estimate the distance between the hydrophones in real-time. To verify the accuracy of our estimation, we compare the result of azimuth estimation with the actual azimuth based on the azimuth estimation of a cooperative sound source in the maritime environment. Our experimental results show that the proposed method correctly estimates the distance between two hydrophones that cannot be directly measured and estimates the position of a cooperative sound source 4 km away with an average deviation of less than 1.2°.

Engine Sonic Load Prediction of Blended Wing Body Aircraft

The sonic load of the engine is the input for cabin noise design and acoustic fatigue verification in civil aircraft. Based on the engine static noise database, an engineering prediction method for blended wing body aircraft engine sonic load in flight is developed. In the process of sonic load prediction, the sound source position correction, geometric diffusion, flight effect and airframe scattering effect of engine component noise are considered. The flight effect and air-frame scattering effect of engine component level noise are simulated and analyzed. The overall sound pressure level distribution and sound load spectrum at typical positions of blended wing body aircraft engine are given. The results show that fan inlet noise is the most important component of the engine sonic load on the BWB aircraft surface, and the maximum value of engine sonic load on the upper surface of blended wing body aircraft is 134 dB, which is higher than that of conventional wing crane aircraft.