scholarly journals Characteristics of Aerodynamic Sound Sources Generated by Coiled Wires in a Uniform Air Flow

2002 ◽  
Author(s):  
Hiroki Matsumoto ◽  
Kohshi Nishida ◽  
Ken-ichi Saitoh
Keyword(s):  
Output Power ◽  
Sound Source ◽  
Velocity Fluctuation ◽  
Air Flow ◽  
Source Region ◽  
Wire Diameter ◽  
Outer Diameter ◽  
Sound Sources ◽  
Aerodynamic Sound

This study deals experimentally with aerodynamic sounds generated by coiled wires in a uniform air flow. The coiled wire is the model of the hair dryer’s heater. In the experiment, the effects of the outer diameter D, wire diameter d and spacing between coils s of the coiled wire on the aerodynamic sound have been clarified. The results of frequency analyses of the aerodynamic sounds show that an aeolian sound is generated by the coiled wire, when s/d is larger than 1. And the peak frequencies of aeolian sounds generated by the coiled wires are higher than the ones generated by a cylinder having the same diameter d. To clarify the characteristics of the aerodynamic sound sources, the directivity of the aerodynamic sound generated by the coiled wire has been examined. And the coherent function between the velocity fluctuation around the coiled wire and the aerodynamic sound has been measured. Moreover the band overall value of coherent output power between the sound and the velocity fluctuation has been calculated. This method has clarified the sound source region of the aeolian sound generated by the coiled wire. These results show that the aeolian sound is generated by the arc part of the coiled wire which is located in the upper side of the air flow.

Role of pinnae and head movements in localizing pure tones 1The authors would like to thank Mr. Remi Humbert for implementing the experiment in Turbo Pascal and for his further assistance.

1999 ◽  
Vol 58 (3) ◽  
pp. 170-179 ◽  
Author(s):  
Barbara S. Muller ◽  
Pierre Bovet
Keyword(s):  
Sound Source ◽  
Head Movement ◽  
Movement Analysis ◽  
Head Movements ◽  
Sound Sources ◽  
Localization Accuracy ◽  
Sound Effects ◽  
Posterior Quadrant ◽  
Localization Performance ◽  
Pure Tones

Twelve blindfolded subjects localized two different pure tones, randomly played by eight sound sources in the horizontal plane. Either subjects could get information supplied by their pinnae (external ear) and their head movements or not. We found that pinnae, as well as head movements, had a marked influence on auditory localization performance with this type of sound. Effects of pinnae and head movements seemed to be additive; the absence of one or the other factor provoked the same loss of localization accuracy and even much the same error pattern. Head movement analysis showed that subjects turn their face towards the emitting sound source, except for sources exactly in the front or exactly in the rear, which are identified by turning the head to both sides. The head movement amplitude increased smoothly as the sound source moved from the anterior to the posterior quadrant.

scholarly journals Towards Robust Multiple Blind Source Localization Using Source Separation and Beamforming

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 532
Author(s):  
Henglin Pu ◽  
Chao Cai ◽  
Menglan Hu ◽  
Tianping Deng ◽  
Rong Zheng ◽  
...  
Keyword(s):  
Source Localization ◽  
Sound Source ◽  
Indoor Localization ◽  
Weighting Function ◽  
Signal To Noise Ratio ◽  
Source Separation ◽  
Sound Source Localization ◽  
Angle Of Arrival ◽  
Sound Sources ◽  
Localization Algorithms

Multiple blind sound source localization is the key technology for a myriad of applications such as robotic navigation and indoor localization. However, existing solutions can only locate a few sound sources simultaneously due to the limitation imposed by the number of microphones in an array. To this end, this paper proposes a novel multiple blind sound source localization algorithms using Source seParation and BeamForming (SPBF). Our algorithm overcomes the limitations of existing solutions and can locate more blind sources than the number of microphones in an array. Specifically, we propose a novel microphone layout, enabling salient multiple source separation while still preserving their arrival time information. After then, we perform source localization via beamforming using each demixed source. Such a design allows minimizing mutual interference from different sound sources, thereby enabling finer AoA estimation. To further enhance localization performance, we design a new spectral weighting function that can enhance the signal-to-noise-ratio, allowing a relatively narrow beam and thus finer angle of arrival estimation. Simulation experiments under typical indoor situations demonstrate a maximum of only 4∘ even under up to 14 sources.

Synthetic individual binaural audio delivery by pinna image processing

2014 ◽  
Vol 10 (3) ◽  
pp. 239-254 ◽  
Author(s):  
Simone Spagnol ◽  
Michele Geronazzo ◽  
Davide Rocchesso ◽  
Federico Avanzini
Keyword(s):  
Sound Source ◽  
Low Complexity ◽  
Head Orientation ◽  
Sound Sources ◽  
Content Type ◽  
Localization Test ◽  
Subjective Measurements ◽  
Head Related Transfer Function ◽  
Practical Implications ◽  
Better Than

Purpose – The purpose of this paper is to present a system for customized binaural audio delivery based on the extraction of relevant features from a 2-D representation of the listener’s pinna. Design/methodology/approach – The most significant pinna contours are extracted by means of multi-flash imaging, and they provide values for the parameters of a structural head-related transfer function (HRTF) model. The HRTF model spatializes a given sound file according to the listener’s head orientation, tracked by sensor-equipped headphones, with respect to the virtual sound source. Findings – A preliminary localization test shows that the model is able to statically render the elevation of a virtual sound source better than non-individual HRTFs. Research limitations/implications – Results encourage a deeper analysis of the psychoacoustic impact that the individualized HRTF model has on perceived elevation of virtual sound sources. Practical implications – The model has low complexity and is suitable for implementation on mobile devices. The resulting hardware/software package will hopefully allow an easy and low-tech fruition of custom spatial audio to any user. Originality/value – The authors show that custom binaural audio can be successfully deployed without the need of cumbersome subjective measurements.

Method for localisation of sound sources and aggregation to an acoustic centre

2021 ◽  
Vol 263 (6) ◽  
pp. 894-906
Author(s):  
Yannik Weber ◽  
Matthias Behrendt ◽  
Tobias Gohlke ◽  
Albert Albers
Keyword(s):  
Sound Source ◽  
Single Point ◽  
Construction Cost ◽  
Measurement Technology ◽  
Front Part ◽  
Sound Sources ◽  
Preliminary Work ◽  
Product Engineering ◽  
Driving Conditions

Preliminary work by the IPEK - Institute of Product Engineering at KIT has shown that the simulated pass-by measurement for exterior noise homologation of vehicles has relevant optimization potential: the measurement can be carried out in smaller halls and with a smaller measurement setup than required by the norm and thus with less construction cost and effort. A prerequisite for this however is the scaling of the entire setup. For the scaling in turn, the sound sources of the vehicle must be combined to a single point sound source - the acoustic centre. Previous approaches for conventional drives assume a static centre in the front part of the vehicle. For complex drive topologies, e.g. hybrid drives, and unsteady driving conditions, however, this assumption is not valid anymore. Therefore, with the help of an acoustic camera, a method for localizing the dominant sound sources of the vehicle and a software-based application for summarizing them to an acoustic centre were developed. The method is able to take into account stationary, unsteady and sudden events in the calculation of the acoustic centre, which is moved as a result. Using substitute sound sources and two vehicles, the method and the used measurement technology were examined and verified for their applicability.

Numerical Study on Air-Reed Instruments With LES

2011 ◽  
Author(s):  
Kin’ya Takahashi ◽  
Masataka Miyamoto ◽  
Yasunori Ito ◽  
Toshiya Takami ◽  
Taizo Kobayashi ◽  
...  
Keyword(s):  
Numerical Study ◽  
Sound Field ◽  
Acoustic Analogy ◽  
Empirical Theory ◽  
Sound Sources ◽  
Aerodynamic Sound ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Semi Empirical ◽  
2D And 3D

The acoustic mechanisms of 2D and 3D edge tones and a 2D small air-reed instrument have been studied numerically with compressible Large Eddy Simulation (LES). Sound frequencies of the 2D and 3D edge tones obtained numerically change with the jet velocity well following Brown’s semi-empirical equation, while that of the 2D air-reed instrument behaves in a different manner and obeys the semi-empirical theory, so called Cremer-Ising-Coltman theory. We have also calculated aerodynamic sound sources for the 2D edge tone and the 2D air-reed instrument relying on Ligthhill’s acoustic analogy and have discussed similarities and differences between them. The sound source of the air-reed instrument is more localized around the open mouth compared with that of the edge tone due to the effect of the strong sound field excited in the resonator.

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.

Relation Between Sound Sources and Vortical Structures in Isotropic Compressible Turbulence

2014 ◽  
Author(s):  
Daiki Terakado ◽  
Taku Nonomura ◽  
Makoto Sato ◽  
Kozo Fujii
Keyword(s):  
Mach Number ◽  
Sound Source ◽  
Compressible Turbulence ◽  
Fine Scale ◽  
Sound Sources ◽  
Vortical Structures ◽  
Scale Structures ◽  
Mach Numbers ◽  
High Mach ◽  
Lighthill Equation

We investigate the relation between vortical structures and sound source in isotropic compressible turbulence by direct numerical simulations with various turbulent Mach numbers. The sound source is obtained numerically from the Lighthill equation. As a first step, we study the sound source from the Reynolds stress, which is the dominant source in flows at low Mach numbers. We investigate, especially, sound source structures around the “coherent fine scale eddies” [1–4] to lead a universal conclusion of sound generation mechanism from the fine scale structures in supersonic flows. We find that the sound source structures around the coherent fine scale eddies show some distorted structures only in high Mach number flows because shocklets appear around the fine scale eddies in those flows. This change in sound source structures around the coherent fine scale eddies does not appear in low and moderate Mach number cases.

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