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TitleA spherical harmonic approach to 3D surround sound systems
Publication TypeConference Paper
Year of Publication2005
AuthorsPoletti, M.
Conference NameForum Acusticum Budapest 2005: 4th European Congress on Acustics
Date Published2005
KeywordsAcoustic fields, Harmonic analysis, Matrix transpose, Mode matching, Plane wave, Point sources, Pseudo-inverse solution, Spherical harmonic coefficient, Spherical harmonics, Surround sound, Three dimensional, Three-dimensional (3D) sound, Wave-front curvature
AbstractThis paper considers the recording and reproduction of three dimensional (3D) sound fields, based on spherical harmonic expansions of the field. It is shown that the plane wave description is insufficient for the description of fields with point sources which have wavefront curvature. The recording of a soundfield requires the measurement of the coefficients of the spherical harmonic expansion. The use of spherical and general arrays for recording the coefficients is discussed. The reproduction of the soundfield requires the resynthesis of the field using the spherical harmonic coefficients. It will be shown that there are two approaches to the determination of the speaker weights. The mode matching approach leads to a pseudo-inverse solution. The simple source approach is formally introduced, and it is shown that its application yields a matrix transpose approach. Computer simulations of soundfield synthesis are given to illustrate the two approaches.

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