Models of sound source directivity that are based on spherical harmonics have been applied in diverse scenarios including wave-based room acoustic simulation, spatial audio, and urban sound propagation. The measurement of directivities of real-world sound sources that are not electroacoustic transducers exhibits fundamental limitations in terms of the accuracy and spatial resolution than can be achieved. Particularly if the directivity is measured only in a plane or over a limited solid angle range, a classical spherical harmonic representation cannot be computed. In many cases it is also such that angle-dependent directivity data are available only at a sparse set of frequencies. We demonstrate in this paper that complete spherical-harmonics-based directivity models can be obtained from such sparse measurement data by interpolating the available data over both the angle and the frequency and then imposing the result onto a spherical wave. We present results based on publicly available directivity data for the human voice as well as for directivity data in the Common Loudspeaker Format. The presented directivity models are available for download.
|Title of host publication||Forum Acusticum|
|Place of Publication||Lyon, France|
|Number of pages||8|
|Publication status||Published - 27 May 2021|
- spherical harmonics
- room simulation