Definition and measurement of random-incidence scattering coefficients

Vorländer, Michael; Mommertz, Eckard

doi:10.1016/s0003-682x(99)00056-0

Cited by 94 publications

(60 citation statements)

References 2 publications

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“…It can be concluded that K.U. Leuven's method presented in (Vorländer, Embrechts, 2004), where over 35 sequences of sine sweep of length 16 s were averaged (the total time of 9 min 20 s), gave values close to the actual ones. In the case of the MLS measurement signal, much smaller discrepancies of the scattering coefficient as a function of the turntable rotational speed were obtained, which allows measurement at higher speeds without sacrificing the accuracy of the results (Fig.…”

Section: Resultsmentioning

confidence: 83%

“…• Measurement for discrete angular positions of the sample is possible, but only for a fully automated measurement set up that allows for measurement time to be reduced to a maximum of one hour, as recommended by (Vorländer, Embrechts, 2004);…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, in the case of sound scattering measurement, the impulse response obtained in a reverberation chamber for a rotating reflecting plane without a sample (reverberation time T3), for the turntable with a sample (reverberation time T4) are characterized by a very low signal-tonoise ratio. This prompted the leading research laboratories to replace the MLS signal with a tunable sine signal (Choi, Leong, 2011;Vorländer, Embrechts, 2004). This allows for obtaining a better signal to noise ratio of the impulse responses obtained (Cox et al, 2006).…”

Section: Problem Descriptionmentioning

confidence: 99%

See 2 more Smart Citations

Test Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber

Kamisiński¹,

Brawata²,

Pilch³

et al. 2012

Archives of Acoustics

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The paper focuses on the problem of test signal selection in determining the sound scattering coefficient in accordance with ISO 17497-1. Research shows that the use of MLS signal is preferred in this procedure. The sine sweep signal, despite its advantages, presents certain limitations if the sample is moving during measurement. An attempt has been made to develop a method that allows for minimization of error, demonstrating the dependence of the obtained values of the sound scattering coefficient on the rotational speed of the turntable and type of test signal. Conditions for the application of the sine sweep signals in continuous and discrete measurements were defined.

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Section: Resultsmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Problem Descriptionmentioning

confidence: 99%

See 1 more Smart Citation

Test Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber

Kamisiński¹,

Brawata²,

Pilch³

et al. 2012

Archives of Acoustics

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show abstract

“…By using the Eq. (4), the random-incidence absorption coefficient α s of the test sample can be obtained (Vorländer and Mommertz 2000), (4) where V is the room volume, c is the speed of sound, and S is the area of the test sample.…”

Section: Reverberation Roommentioning

confidence: 99%

Recent Advances in the Sound Insulation Properties of Bio-based Materials

Zhu¹,

Kim²,

Wang³

et al. 2013

BioResources

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Many bio-based materials, which have lower environmental impact than traditional synthetic materials, show good sound absorbing and sound insulation performances. This review highlights progress in sound transmission properties of bio-based materials and provides a comprehensive account of various multiporous bio-based materials and multilayered structures used in sound absorption and insulation products. Furthermore, principal models of sound transmission are discussed in order to aid in an understanding of sound transmission properties of bio-based materials. In addition, the review presents discussions on the composite structure optimization and future research in using co-extruded wood plastic composite for sound insulation control. This review contributes to the body of knowledge on the sound transmission properties of bio-based materials, provides a better understanding of the models of some multiporous bio-based materials and multilayered structures, and contributes to the wider adoption of bio-based materials as sound absorbers.

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“…Vorländer and Mommertz in [14] have proposed a method of measuring diusion properties of a structure in the scattered eld, dening the randomincidence scattering coecient (usually denoted s) as the ratio of energy reected in the non-specular direction and the total acoustic energy reected from a structure. The quantity is determined in conditions close to those prevailing in actual rooms and for that reason the coecient is commonly used in dedicated room-acoustics calculation algorithms.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Pressure and Intensity Methods in Evaluating the Directional Diffusion Coefficient

2013

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The directional diusion coecient characterizes directional uniformity of acoustic energy reected from a structure. The goal of the paper is to check whether dierent measurement methods of that coecient give comparable results and can be used for dierent diusing structures. ISO 17497-2:2012 recommends two basic measurement methods for this parameter, both based on sound pressure analysis. In the rst method, one microphone and a measurement manipulator is used (the space method), while in the second one, 19 microphones placed on the sound-reecting plane are required (the boundary method). In the standard it is assumed (as usually in the room acoustics), that the acoustic energy is proportional to the square of sound pressure, what is true only for the plane wave. Correctness of this assumption was checked by the modied space method where the sound intensity probe was installed instead of microphone. The test revealed that pressure methods gave comparable results for both low-and high-diusion structures, with the boundary method giving moderately higher values for low-diusion structures and slightly higher for high-diusion structures. The results obtained in the intensity method were comparable with the pressure method except for the 2000 Hz frequency range.

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Definition and measurement of random-incidence scattering coefficients

Cited by 94 publications

References 2 publications

Test Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber

Test Signal Selection for Determining the Sound Scattering Coefficient in a Reverberation Chamber

Recent Advances in the Sound Insulation Properties of Bio-based Materials

Comparison of Pressure and Intensity Methods in Evaluating the Directional Diffusion Coefficient

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