Evaluation of Uncertainty Contributions of Measurement Surface and Number of Microphone Positions in Determination of Sound Power Levels

• Authors: E. Bilgic , H. Mutaf , C. Kirbas , E. Sadikoglu
• Languages of publication: EN

Abstracts

EN

Sound power level of a noise source is determined by means of sound pressure level or sound intensity level measurements performed in accordance to relevant ISO standards. The determination of sound power level according to ISO 3744, 3745 and 3746 standards is used for free field or for approximated free field conditions. Kinds of measurement surfaces, enveloping the noise source, number of microphones and their positions over the measurement surface are stated in the applied ISO standard. The effects of measurement surface and number of microphone positions on the determination of sound power level were investigated theoretically. As a measurement surface; hemisphere, parallelepiped rectangular box and cylindrical surfaces were selected. Key and additional microphone positions were taken into account in the calculations as well. Sound pressure levels of a commercially available reference sound source were measured in hemi-anechoic room using FFT with 4 Hz steps and also at 1/1, 1/3, 1/12 and 1/24 octave bands for all surfaces defined in ISO 3744 and 3746 standards. Sound power level, directivity index and uncertainty contributions resulting from measurement surfaces and number of microphone positions were calculated by using data obtained in measurements. In this paper the theoretical and experimental results are presented.

Keywords

EN

06.20.Dk; 06.20.fb

Discipline

• 06.20.fb: Standards and calibration
• 06.20.Dk: Measurement and error theory

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2017
• Volume: 132
• Issue: 3
• Pages: 642-649

Dates

published

2017-09

Contributors

author

E. Bilgic

• TÜBİTAK Ulusal Metroloji Enstitüsü (UME), Gebze Kocaeli, Turkey

author

H. Mutaf

• Gaziantep University, Department of Physics Engineering, Şehitkamil, Turkey

author

C. Kirbas

• TÜBİTAK Ulusal Metroloji Enstitüsü (UME), Gebze Kocaeli, Turkey

author

E. Sadikoglu

• TÜBİTAK Ulusal Metroloji Enstitüsü (UME), Gebze Kocaeli, Turkey

References

• [1] ISO 3745, Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Precision methods for anechoic rooms and hemi-anechoic rooms, International Organization for Standardization, Geneva 2012 http://www.iso.org/standard/45362.html
• [2] ISO 3744, Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Engineering methods for an essentially free field over a reflecting plane, International Organization for Standardization, Geneva 2010 http://www.iso.org/standard/52055.html
• [3] ISO 3746, Acoustics - Determination of sound power levels and sound energy levels of noise sources using sound pressure - Survey method using an enveloping measurement surface over a reflecting plane, International Organization for Standardization, Geneva 2010 http://www.iso.org/standard/52056.html
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• [7] ISO 9614-1, Acoustics - Determination of sound power levels of noise sources using sound intensity - Part 1: Measurement at discrete points, International Organization for Standardization, Geneva 1993 http://www.iso.org/standard/17427.html
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• [13] C. Kirbas, H. Andersson, C. Guglielmone, V. Wittstock, E. Bilgic, in: INTER-NOISE 2016, 45th Int. Congress and Exposition on Noise Control Engineering, 2016, p. 6737
• [14] K. Voelkel, V. Wittstock, in: INTER-NOISE 2016, 45th Int. Congress and Exposition on Noise Control Engineering, 2016, p. 6803
• [15] H. Andersson, V. Wittstock, in: INTER-NOISE 2016, 45th Int. Congress and Exposition on Noise Control Engineering, 2016, p. 6783

Identifiers

DOI

10.12693/APhysPolA.132.642