Acoustically Coupled Microphone Arrays

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
R. N. Miles
Keyword(s):  
Mechanical Properties ◽  
Microphone Arrays ◽  
Dramatic Improvement ◽  
Small Animals ◽  
Noise Performance ◽  
Directional Response ◽  
Sound Sources ◽  
Acoustic Coupling ◽  
Back Volume ◽  
Acoustic Sensitivity

An analysis is presented of the performance benefits that can be achieved by introducing acoustic coupling between the diaphragms in an array of miniature microphones. The introduction of this coupling is analogous to the principles employed in the ears of small animals that are able to localize sound sources. Measured results are shown, which indicate a dramatic improvement in acoustic sensitivity, and noise performance can be achieved by packaging a pair of small microphones so that their diaphragms share a common back volume of air. This is also shown to reduce the adverse effects on directional response of mismatches in the mechanical properties of the microphones.

scholarly journals Feasibility of Discriminating UAV Propellers Noise from Distress Signals to Locate People in Enclosed Environments Using MEMS Microphone Arrays

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 597
Author(s):  
Alberto Izquierdo ◽  
Lara del Val ◽  
Juan J. Villacorta ◽  
Weikun Zhen ◽  
Sebastian Scherer ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Micro Electro Mechanical System ◽  
Microphone Arrays ◽  
Heat Sources ◽  
Sound Sources ◽  
Mems Microphone ◽  
Aerial Vehicle ◽  
Acoustic Array ◽  
Alternative Techniques ◽  
The University

Detecting and finding people are complex tasks when visibility is reduced. This happens, for example, if a fire occurs. In these situations, heat sources and large amounts of smoke are generated. Under these circumstances, locating survivors using thermal or conventional cameras is not possible and it is necessary to use alternative techniques. The challenge of this work was to analyze if it is feasible the integration of an acoustic camera, developed at the University of Valladolid, on an unmanned aerial vehicle (UAV) to locate, by sound, people who are calling for help, in enclosed environments with reduced visibility. The acoustic array, based on MEMS (micro-electro-mechanical system) microphones, locates acoustic sources in space, and the UAV navigates autonomously by closed enclosures. This paper presents the first experimental results locating the angles of arrival of multiple sound sources, including the cries for help of a person, in an enclosed environment. The results are promising, as the system proves able to discriminate the noise generated by the propellers of the UAV, at the same time it identifies the angles of arrival of the direct sound signal and its first echoes reflected on the reflective surfaces.

Layout Optimization of Cooperative Distributed Microphone Arrays Based on Estimation of Source Separation Performance

2017 ◽  
Vol 29 (1) ◽  
pp. 83-93
Author(s):  
Kouhei Sekiguchi ◽  
◽  
Yoshiaki Bando ◽  
Katsutoshi Itoyama ◽  
Kazuyoshi Yoshii
Keyword(s):  
Mobile Robots ◽  
Microphone Array ◽  
Source Separation ◽  
Microphone Arrays ◽  
Separation Performance ◽  
Sound Sources ◽  
Multiple Mobile Robots ◽  
Position Information ◽  
Reconfigurable Array ◽  
Source Signals

[abstFig src='/00290001/08.jpg' width='300' text='Optimizing robot positions for source separation' ] The active audition method presented here improves source separation performance by moving multiple mobile robots to optimal positions. One advantage of using multiple mobile robots that each has a microphone array is that each robot can work independently or as part of a big reconfigurable array. To determine optimal layout of the robots, we must be able to predict source separation performance from source position information because actual source signals are unknown and actual separation performance cannot be calculated. Our method thus simulates delay-and-sum beamforming from a possible layout to calculate gain theoretically, i.e., the expected ratio of a target sound source to other sound sources in the corresponding separated signal. Robots are moved into the layout with the highest average gain over target sources. Experimental results showed that our method improved the harmonic mean of signal-to-distortion ratios (SDRs) by 5.5 dB in simulation and by 3.5 dB in a real environment.

Online Localization of Multiple Sound Sources and Multiple Robots with Asynchronous Microphone Arrays

2016 ◽  
Vol 2016 (0) ◽  
pp. 1A2-09b5
Author(s):  
Kouhei Sekiguchi ◽  
Yoshiaki bando ◽  
Keisuke Nakamura ◽  
Kazuhiro Nakadai ◽  
Katsutoshi Itoyama ◽  
...  
Keyword(s):  
Microphone Arrays ◽  
Multiple Robots ◽  
Sound Sources

Effect of Cu on Nanoscale Precipitation Evolution and Mechanical Properties of a Fe–NiAl Alloy

2017 ◽  
Vol 23 (2) ◽  
pp. 350-359 ◽  
Author(s):  
Qin Shen ◽  
Hao Chen ◽  
Wenqing Liu
Keyword(s):  
Mechanical Properties ◽  
Atom Probe Tomography ◽  
Diffusion Rate ◽  
Atom Probe ◽  
Peak Hardness ◽  
Dramatic Improvement ◽  
Number Density ◽  
Cu Alloy ◽  
Tension Tests ◽  
Nial Alloy

AbstractThe microstructural evolution of precipitation in two model alloys, Fe–NiAl and Fe–NiAl–Cu, was investigated during aging at 500°C for different times using atom probe tomography (APT). The APT results reveal that the addition of Cu effectively increases the number density of NiAl precipitates. This is attributed to Cu promoting the nucleation of NiAl particles by increasing the chemical driving force and decreasing the interfacial energy. The NiAl precipitates of the Fe–NiAl–Cu alloy grow and coarsen at a slower rate than that of the Fe–NiAl alloy, mainly due to the slower diffusion rate of the Cu atoms. The mechanical properties of the two alloys were characterized by Vickers hardness and tension tests. It was found that the addition of Cu results in the formation of core–shell precipitates with a Cu-rich core and a NiAl shell, leading to a dramatic improvement of peak hardness and strength. The effect of Cu on precipitation strengthening is discussed in terms of chemical strength and coherency strength.

Reduction of Vehicle Interior Noise Using Our New Structural-Acoustic Sensitivity Analysis Methods

1991 ◽  
Author(s):  
Ichiro Hagiwara ◽  
Wakae Kozukue ◽  
Zheng-Dong Ma
Keyword(s):  
Sensitivity Analysis ◽  
Coupled System ◽  
Interior Noise ◽  
Design Stage ◽  
Vehicle Interior ◽  
Acoustic Coupling ◽  
Analysis Process ◽  
Analysis Methods ◽  
Orthogonality Conditions ◽  
Acoustic Sensitivity

Abstract Since interior noise has a strong effect on vehicle salability, it is particularly important to be able to estimate noise levels accurately by means of simulation at the design stage. The use of sensitivity analysis makes it easy to determine how the analytical model should be modified or the structure optimized for the purpose of reducting vibration and noise of the structural-acoustic systems. The present work focused on a structural-acoustic coupling problem. As the coefficient matrices of a coupled structural-acoustic system are not symmetrical, the conventional orthogonality conditions obtained in structural dynamics generally do not hold true for the coupled system. To overcome this problem, the orthogonality and normalization conditions of a coupled system were derived by us. In this paper, our sensitivity analysis methods are applied to an interior noise problem of a cabin model. It will be shown how a sensitivity analysis process is performed, and how vibration and noise can be reduced.

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