Post-processing and center adjustment of measured directivity data of musical instruments

Martin Pollow , Gottfried Behler , Michael Vorländer

Surrounding spherical microphone arrays can capture the radiation pattern of sound sources placed inside the array. Depending on the exact positioning of the sound source, the obtained measurement results vary, as amplitude and phase differences arise due to the different traveling time of the radiated sound. Using the spherical harmonic decomposition of the sound field, it is noticeable that displaced sound sources need a much higher number of modal components for an accurate description. As surrounding spherical microphone arrays are severely limited in their spatial resolution correct centering is crucial for higher frequencies. In practice, however, a precise alignment to the physical center of the array is impossible. With the help of re-alignment algorithms it is possible to virtually shift the sound source to the center of the array to allow a more accurate description in the spherical harmonic domain. Alternatively, a magnitude only approach can be employed, resulting in a more robust representation regarding incorrect centering in the array. In this contribution different post-processing strategies are presented with the goal to provide directivity patterns of musical instruments for application in both measurement and simulation.

Mots clés: directivity; spherical harmonics; microphone array

Domaines: Acoustique [physics.class-ph]

Martin Pollow, Gottfried Behler, Michael Vorländer. Post-processing and center adjustment of measured directivity data of musical instruments. Acoustics 2012, Apr 2012, Nantes, France. ⟨hal-00811212⟩