A sound source can generally be characterized by three physical properties: timber (spectral and temporal response), loudness and directivity. Although loudspeakers give a faithful reproduction of timber and loudness, their own directivity can conflict with the directivity of the source they aim at reproducing. In the first section of this paper, we describe a general method for reproducing different sorts of directivity patterns using a multi-loudspeaker source. In the second section we apply this method to a particular source with twelve loudspeakers grouped into few subsets for fitting the first zonal harmonics (spherical harmonics with axial symetry). Theoretical results are presented and compared with experimental measurements. These results show a good agreement between the prediction and the experiment below 500 Hz. But it appears, above this frequency, that our source don't correspond with the directivity patterns. In the third section we discuss the limitation of our work and show how our results could be improved by modifying the source geometry and increasing the number of loudspeakers independently driven.
Contribution au colloque ou congrès : ISMA: International Symposium of Music Acoustics