Correlating Noise Sources Identified by Beamforming with Sound Power Measurements

Washburn, Karl B.; Frazer, Tony; Kunio, Jason

doi:10.4271/2005-01-2510

Cited by 7 publications

(2 citation statements)

References 1 publication

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“…In this respect, both the sensitivity difference as well as the phase mismatch will have an effect on the result. Calibration plays an important role when trying to measure absolute levels that are used for instance for an estimate of the sound power of a source as carried out by Washburn et al 12 The sensitivity calibration error is modeled as a multiplicative random value with a mean value of 0 dB and a standard deviation between 0.5 and 10 dB which is constant over frequency. To investigate the effect of the sensor phase mismatch a random phase offset (also constant over frequency) with a standard deviation between 5 and 120 degrees is applied to the simulated pressure data.…”

Section: Sensor Calibration Errorsmentioning

confidence: 99%

Influence of various uncertainty factors on the result of beamforming measurements

Müller-Trapet¹,

Dietrich²,

Vorländer³

2011

Noise Control Eng. J.

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In a previous publication by the authors, a virtual measurement environment for sound-source localization on vibrating structures was presented. Based on surface velocity data obtained from Laser-Scanning-Vibrometry measurements, the Boundary-Element-Method (BEM) is used to simulate the sound radiation from a vibrating plate towards a microphone array under ideal conditions. The advantage of this approach is that the measurement conditions can be perfectly controlled and real sources can be considered, without restrictions on the type of source. The virtual measurement environment will now be used to investigate the effect of some of the uncertainties that can be encountered during beamforming measurements. For the most common planar array geometries, the beamforming source maps will be calculated for varying Signal-to-Noise Ratios (SNR) and different array imperfections (uncertainties in the microphone locations and deviation from the omni-directional directivity pattern of the microphones). As a measure of comparison, the two-dimensional normalized cross-correlation coefficient between the ideal source map and the source map with added uncertainties will be evaluated and discussed. © 2011 Institute of Noise Control Engineering.

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Section: Sensor Calibration Errorsmentioning

confidence: 99%

Influence of various uncertainty factors on the result of beamforming measurements

Müller-Trapet¹,

Dietrich²,

Vorländer³

2011

Noise Control Eng. J.

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“…Sound intensity measurement offers several ways of doing this which have considerable advantages over older techniques. Contour plots give a more detailed picture of the sound field generated by a source [20]. Sound intensity measurements normal to the surface are made from a number of equally spaced points on the surface.…”

Section: Introductionmentioning

confidence: 99%

Noise and vibration analysis for automotive radiator cooling fan

Razak

Sani

Azmi

et al. 2017

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. This paper aims to analyse the noise and vibration of the automotive radiator specifically focused on its cooling fan for different fan conditions and different coolants used namely Ethylene Glycol (EG) water-based and Titanium Oxide (TiO 2 ) nanofluid. Noise source identification is carried out by utilizing the sound intensity mapping method while an accelerometer is used to measure the vibration results. Both of these experiments are conducted when the fan was both in static and working conditions. The maximum cooling fan speed for the working fan detected by a tachometer for EG water-based is 1990 rpm while TiO 2 nanofluid is 2030 rpm. The difference in speed is due to the different physical properties such viscosity of each coolant has where TiO 2 nanofluid has lower viscosity than EG water-based. The maximum sound power level produced by EG water-based is 53.73 dB while TiO 2 nanofluid is 101.94 dB. Meanwhile, the vibration frequencies of EG water-based are higher than TiO 2 nanofluid. The noise level increases with the cooling fan speed but decreases with the vibration frequency. Apart from studying the noise and vibration of the automotive radiator, this research also analysed the potential application using nanofluid due to its great properties according to its major use in the heat transfer enhancement. As a conclusion, nanofluid as a radiator coolant could improve heat transfer rate, and could also reduce the presence of vibration in the automotive cooling system.

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Acoustic source localization with microphone arrays for remote noise monitoring in an Intensive Care Unit

et al. 2018

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An approach is described to apply spatial filtering with microphone arrays to localize acoustic sources in an Intensive Care Unit (ICU). This is done to obtain more detailed information about disturbing noise sources in the ICU with the ultimate goal of facilitating the reduction of the overall background noise level, which could potentially improve the patients’ experience and reduce the time needed for recovery. This paper gives a practical description of the system, including the audio hardware setup as well as the design choices for the microphone arrays. Additionally, the necessary signal processing steps required to produce meaningful data are explained, focusing on a novel clustering approach that enables an automatic evaluation of the spatial filtering results. This approach allows the data to be presented to the nursing staff in a way that enables them to act on the results produced by the system.

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Correlating Noise Sources Identified by Beamforming with Sound Power Measurements

Cited by 7 publications

References 1 publication

Influence of various uncertainty factors on the result of beamforming measurements

Influence of various uncertainty factors on the result of beamforming measurements

Noise and vibration analysis for automotive radiator cooling fan

Acoustic source localization with microphone arrays for remote noise monitoring in an Intensive Care Unit

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