A note on determination of the diffuse-field sensitivity of microphones using the reciprocity technique

Barrera‐Figueroa, Salvador; Rasmussen, Knud; Jacobsen, Finn

doi:10.1121/1.2950089

Cited by 6 publications

(3 citation statements)

References 18 publications

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“…Calibration methods based on diffuse sound field shall finally be investigated. This method has been demonstrated in air by DFM for microphones [16] and recently in a laboratory water tank by VNIIFTRI (Russia) for a receiver attached to a towed body or recorder in one third-octave band levels [17], [18]. This approach accounts for the measured sound wave that is incident on the hydrophone as well as the measured sound that has been scattered off the recorder body.…”

Section: Calibration Methodologies For Autonomous Recordersmentioning

confidence: 99%

Calibration standards for hydrophones and autonomous underwater noise recorders for frequencies below 1 kHz: current activities of EMPIR “UNAC-LOW” project

et al. 2018

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The project entitled “UNderwater Acoustic Calibration standards for frequencies beLOW 1 kHz” (“UNAC-LOW”), currently active within the European Metrology Programme for Innovation and Research (EMPIR), is presented by describing its objectives and current activities. The project aims at developing the metrological capacity of the European Union (EU) for the calibration of hydrophones and autonomous recording systems for the frequency range between 20 Hz and 1 kHz, for which traceability is presently not fully available. In this way, EU metrological capacities for absolute measurement of underwater sound will be improved, with a direct effect on the implementation of regulation and EU Directives that require underwater acoustic measurements to be traceable. After having completed the initial project tasks regarding the review of existing methods and the design of the experimental setups, comparison measurements between the project partners are currently under way and their results will be validated and presented upon project end after first quarter of 2019. To ensure long-term operation of the calibration capabilities by each partner, a coherent EU metrology strategy for underwater acoustics will be developed as one of the main project outcomes. Current activities include the implementation of the calibration setups developed in earlier stages of the project for both hydrophones and autonomous recorders. The methods that shall be used for hydrophones are the pressure method in a closed chamber and the standing wave tube method. For autonomous recorders, in addition to the above methods, calibrations will be performed using free-field methods in different open-water test sites possessing suitable characteristics for low frequency measurements.

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Section: Calibration Methodologies For Autonomous Recordersmentioning

confidence: 99%

Calibration standards for hydrophones and autonomous underwater noise recorders for frequencies below 1 kHz: current activities of EMPIR “UNAC-LOW” project

et al. 2018

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“…Details can be found in Ref. 5. Similarly, results of the random-incidence correction are only presented from 1 kHz for LS1 microphones and from 2 kHz for LS2 microphones.…”

Section: B Radiation Impedance and Diffuse-field Response Of A Micromentioning

confidence: 99%

“…More recently, Bietz and Vorländer 4 studied the possibility of performing simultaneous free-field and diffusefield calibration using a time-selective technique. BarreraFigueroa et al 5 made some observations about the accuracy of the reciprocity estimate in a diffuse field due to the statistical characteristics of the sound field in a reverberant room.…”

Section: Introductionmentioning

confidence: 99%

Radiation impedance of condenser microphones and their diffuse-field responses

Barrera‐Figueroa¹,

Rasmussen²,

Jacobsen

2010

The Journal of the Acoustical Society of America

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The relation between the diffuse-field response and the radiation impedance of a microphone has been investigated. Such a relation can be derived from classical theory. The practical measurement of the radiation impedance requires ͑a͒ measuring the volume velocity of the membrane of the microphone and ͑b͒ measuring the pressure on the membrane of the microphone. The first measurement is carried out by means of laser vibrometry. The second measurement cannot be implemented in practice. However, the pressure on the membrane can be calculated numerically by means of the boundary element method. In this way, a hybrid estimate of the radiation impedance is obtained. The resulting estimate of the diffuse-field response is compared with experimental estimates of the diffuse-field response determined using reciprocity and the random-incidence method. The different estimates are in good agreement at frequencies below the resonance frequency of the microphone. Although the method may not be of great practical utility, it provides a useful validation of the estimates obtained by other means.

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Primary calibration in acoustics metrology

Milhomem¹,

Soares²

2015

J. Phys.: Conf. Ser.

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A note on determination of the diffuse-field sensitivity of microphones using the reciprocity technique

Cited by 6 publications

References 18 publications

Calibration standards for hydrophones and autonomous underwater noise recorders for frequencies below 1 kHz: current activities of EMPIR “UNAC-LOW” project

Calibration standards for hydrophones and autonomous underwater noise recorders for frequencies below 1 kHz: current activities of EMPIR “UNAC-LOW” project

Radiation impedance of condenser microphones and their diffuse-field responses

Primary calibration in acoustics metrology

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