Sound Field Control Using a Limited Number of Loudspeakers

We treat the problem of optimizing N digital filters for a sound system consisting of N loudspeaker inputs and M measurement output positions, with the objective of creating a target sound field described by M prescribed transfer functions, one for each measurement position. We pose the problem in a control-theoretic framework, with the main interest on practical car audio systems, i.e. where N ≪M. The solution is verified in listening experiments and by objective means. It is shown that the proposed framework provides a unified solution to the problem of equalizer design, crossover design, delay and level calibration, sum-response optimization, and up-mixing (the process of routing 2-channel or 5.1-channel source material to N loudspeaker outputs).

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