The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation

C.C.J.M. Hak, R.H.C. Wenmaekers, J.P.M. Hak, A.P.D. van Luxemburg

Onderzoeksoutput: Hoofdstuk in Boek/Rapport/CongresprocedureConferentiebijdrageAcademic

11 Citaties (Scopus)
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Uittreksel

An omnidirectional sound source is commonly used in room acoustical measurements. The omnidirectional directivity is usually approached by placing 12 loudspeakers in a regular 12-face polyhedron, called a dodecahedron. In the ISO 3382-1 standard on the measurement of room acoustical parameters, limits are imposed on the maximum allowable deviation from omnidirectional directivity of the sound source. If this deviation approaches the limits, it is recommended to take a rotational average over at least three positions around the source. The average over three equal-angular positions in the horizontal plane of a dodecahedron sound source proves to be unreliable due to the particular geometry of the dodecahedron. In this research, the impact of the stepwise rotation method on the measured directivity deviation of a dodecahedron sound source is investigated. This is done by determining the maximum directivity deviation from rotation measurements over a whole number of equal-angular steps varying from 1 to 8. The measurements have been performed in a concert hall at 1, 5 and 18 meters distance using a standard dodecahedron loudspeaker, a turntable and stationary pseudorandom white noise. It was found that the maximum directivity deviation from average within the critical distance of a dodecahedron sound source is ± 2 dB, when determined from 3 equal-angular positions. Only when using 5, 7 or 8 equal-angular positions, the maximum directivity deviation is reduced to ± 0.5 dB at all distances.
Originele taal-2Engels
TitelProceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011
UitgeverijEAA
Pagina's1875-1879
ISBN van geprinte versie978-84-694-1520-7
StatusGepubliceerd - 2011
Evenement6th Forum Acusticum 2011 (FA 2011), 27 June - 01 July 2011, Aalborg, Denmark - Aalborg, Denemarken
Duur: 27 jun 20111 jul 2011

Congres

Congres6th Forum Acusticum 2011 (FA 2011), 27 June - 01 July 2011, Aalborg, Denmark
LandDenemarken
StadAalborg
Periode27/06/111/07/11
AnderForum Acusticum

Vingerafdruk

directivity
deviation
acoustics
loudspeakers
rooms
polyhedrons
white noise
geometry

Citeer dit

Hak, C. C. J. M., Wenmaekers, R. H. C., Hak, J. P. M., & van Luxemburg, A. P. D. (2011). The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation. In Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011 (blz. 1875-1879). EAA.
Hak, C.C.J.M. ; Wenmaekers, R.H.C. ; Hak, J.P.M. ; van Luxemburg, A.P.D. / The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation. Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011. EAA, 2011. blz. 1875-1879
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Hak, CCJM, Wenmaekers, RHC, Hak, JPM & van Luxemburg, APD 2011, The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation. in Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011. EAA, blz. 1875-1879, Aalborg, Denemarken, 27/06/11.

The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation. / Hak, C.C.J.M.; Wenmaekers, R.H.C.; Hak, J.P.M.; van Luxemburg, A.P.D.

Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011. EAA, 2011. blz. 1875-1879.

Onderzoeksoutput: Hoofdstuk in Boek/Rapport/CongresprocedureConferentiebijdrageAcademic

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AU - van Luxemburg, A.P.D.

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N2 - An omnidirectional sound source is commonly used in room acoustical measurements. The omnidirectional directivity is usually approached by placing 12 loudspeakers in a regular 12-face polyhedron, called a dodecahedron. In the ISO 3382-1 standard on the measurement of room acoustical parameters, limits are imposed on the maximum allowable deviation from omnidirectional directivity of the sound source. If this deviation approaches the limits, it is recommended to take a rotational average over at least three positions around the source. The average over three equal-angular positions in the horizontal plane of a dodecahedron sound source proves to be unreliable due to the particular geometry of the dodecahedron. In this research, the impact of the stepwise rotation method on the measured directivity deviation of a dodecahedron sound source is investigated. This is done by determining the maximum directivity deviation from rotation measurements over a whole number of equal-angular steps varying from 1 to 8. The measurements have been performed in a concert hall at 1, 5 and 18 meters distance using a standard dodecahedron loudspeaker, a turntable and stationary pseudorandom white noise. It was found that the maximum directivity deviation from average within the critical distance of a dodecahedron sound source is ± 2 dB, when determined from 3 equal-angular positions. Only when using 5, 7 or 8 equal-angular positions, the maximum directivity deviation is reduced to ± 0.5 dB at all distances.

AB - An omnidirectional sound source is commonly used in room acoustical measurements. The omnidirectional directivity is usually approached by placing 12 loudspeakers in a regular 12-face polyhedron, called a dodecahedron. In the ISO 3382-1 standard on the measurement of room acoustical parameters, limits are imposed on the maximum allowable deviation from omnidirectional directivity of the sound source. If this deviation approaches the limits, it is recommended to take a rotational average over at least three positions around the source. The average over three equal-angular positions in the horizontal plane of a dodecahedron sound source proves to be unreliable due to the particular geometry of the dodecahedron. In this research, the impact of the stepwise rotation method on the measured directivity deviation of a dodecahedron sound source is investigated. This is done by determining the maximum directivity deviation from rotation measurements over a whole number of equal-angular steps varying from 1 to 8. The measurements have been performed in a concert hall at 1, 5 and 18 meters distance using a standard dodecahedron loudspeaker, a turntable and stationary pseudorandom white noise. It was found that the maximum directivity deviation from average within the critical distance of a dodecahedron sound source is ± 2 dB, when determined from 3 equal-angular positions. Only when using 5, 7 or 8 equal-angular positions, the maximum directivity deviation is reduced to ± 0.5 dB at all distances.

M3 - Conference contribution

SN - 978-84-694-1520-7

SP - 1875

EP - 1879

BT - Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011

PB - EAA

ER -

Hak CCJM, Wenmaekers RHC, Hak JPM, van Luxemburg APD. The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation. In Proceedings of Forum Acusticum, Aalborg, 27 June-1 July 2011. EAA. 2011. blz. 1875-1879