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TitleTwo dimensional sound field reproduction using higher order sources to exploit room reflections
Publication TypeJournal Article
Year of Publication2014
AuthorsBetlehem, T., and Poletti M.A.
JournalJournal of the Acoustical Society of America
Pagination1820 - 1833
Date Published2014
ISSN00014966 (ISSN)
KeywordsAcoustic field measurement, Acoustic fields, Acoustic transfer functions, acoustics, Architectural acoustics, Diffuse fields, Digital filters, Directive property, Loudspeakers, Measurement errors, Microphone arrays, Monopole source, Reverberant room, Reverberation, Sound field reproduction, Wall reflection
AbstractIn this paper, sound field reproduction is performed in a reverberant room using higher order sources (HOSs) and a calibrating microphone array. Previously a sound field was reproduced with fixed directivity sources and the reverberation compensated for using digital filters. However by virtue of their directive properties, HOSs may be driven to not only avoid the creation of excess reverberation but also to use room reflection to contribute constructively to the desired sound field. The manner by which the loudspeakers steer the sound around the room is determined by measuring the acoustic transfer functions. The requirements on the number and order N of HOSs for accurate reproduction in a reverberant room are derived, showing a 2N + 1-fold decrease in the number of loudspeakers in comparison to using monopole sources. HOSs are shown applicable to rooms with a rich variety of wall reflections while in an anechoic room their advantages may be lost. Performance is investigated in a room using extensions of both the diffuse field model and a more rigorous image-source simulation method, which account for the properties of the HOSs. The robustness of the proposed method is validated by introducing measurement errors. © 2014 Acoustical Society of America.

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