This paper presents an approach for the directional filtering in an Ambisonic sound scene. The filtering is described in the angular domain and is done in the Ambisonic domain thanks to a spherical Fourier transform. When dealing with finite-order Ambisonics, this operation can be expressed as a matrix operation. Two directional filtering cases are discussed: the directional Dirac and the case of beampattern with known spherical Fourier transform. Theoretical analysis is provided: It is shown that the required order after directional filtering should increase to avoid the loss of information. An implementation is introduced: It allows variable selectivity of the directional filtering along with real-time interaction.

Authors: Lecomte, Pierre; Gauthier, Philippe-Aubert; Berry, Alain; Garcia, Alexandre; Langrenne, Christophe
Affiliations: Université de Lyon, Lyon, France; University de Sherbrooke, Sherbrooke, Quebec, Canada; Conservatoire National des Arts et Métiers, Paris, France(See document for exact affiliation information.)
AES Conference: 2018 AES International Conference on Spatial Reproduction - Aesthetics and Science (July 2018)
Paper Number: P7-1
Publication Date: July 30, 2018 Import into BibTeX
Session Subject: ambisonics; directional filtering; spherical array beamforming
Permalink: https://www.aes.org/e-lib/browse.cfm?elib=19622

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