### Uittreksel

Originele taal-2 | Engels |
---|---|

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

Uitgeverij | EAA |

Pagina's | 1875-1879 |

ISBN van geprinte versie | 978-84-694-1520-7 |

Status | Gepubliceerd - 2011 |

Evenement | 6th Forum Acusticum 2011 (FA 2011), 27 June - 01 July 2011, Aalborg, Denmark - Aalborg, Denemarken Duur: 27 jun 2011 → 1 jul 2011 |

### Congres

Congres | 6th Forum Acusticum 2011 (FA 2011), 27 June - 01 July 2011, Aalborg, Denmark |
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Land | Denemarken |

Stad | Aalborg |

Periode | 27/06/11 → 1/07/11 |

Ander | Forum Acusticum |

### Vingerafdruk

### Citeer dit

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

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*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.

Onderzoeksoutput: Hoofdstuk in Boek/Rapport/Congresprocedure › Conferentiebijdrage › Academic

TY - GEN

T1 - The Source Directivity of a Dodecahedron Sound Source determined by Stepwise Rotation

AU - Hak, C.C.J.M.

AU - Wenmaekers, R.H.C.

AU - Hak, J.P.M.

AU - van Luxemburg, A.P.D.

PY - 2011

Y1 - 2011

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 -