Dual-layer loudspeaker array for multiple listening zones

Fazi, Filippo M., Casagrande Hirono, Fabio and Nelson, Philip A. (2012) Dual-layer loudspeaker array for multiple listening zones. Acoustics 2012 Hong Kong, Hong Kong, Hong Kong. 12 - 17 May 2012.

Record type: Conference or Workshop Item (Other)

Abstract

A dual-layer array consisting of sixteen small (1") loudspeakers has been built for simultaneous transmission of audio signals to multiple listeners occupying different regions of the space. The audio signals are filtered through a bank of FIR filters, computed using a Least Mean Squares (LMS) approach with regularization. The plant matrix of the array, representing the transfer functions between the loudspeakers and a set of control points, was measured in the anechoic chamber of the ISVR and was used in the filter matrix calculation.

It is shown that the selection of both the number and location of the control points has direct impact on the condition number of the plant matrix, on the frequency response of the digital filters, on the frequency response of the reproduced signals, and on the acoustic radiation pattern of the array.

Results are shown for several application cases, which demonstrate also the capability of controlling independently the sound radiation to the front and to the back of the dual-layer array.

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