Mitigation of Nonlinear Distortion in Sound Zone Control by Constraining Individual Loudspeaker Driver Amplitudes

Loudspeaker drivers are subject to nonlinear distortion in the low frequency range at high input levels. In sound zone control, distortion not only reduces the acoustic contrast between zones, but also gives perceived artefacts. Standard sound zone methods, such as acoustic contrast control, apply a constraint to the overall input power, but individual loudspeaker drivers are not controlled and the nonlinear distortion is mainly produced by the loudspeaker drivers with the highest input power. We investigate a sound zone control algorithm where amplitude limits are applied on a per-loudspeaker-driver basis, and its effect on the mitigation of nonlinear distortion. Experiments with pure-tone signals show that this approach improves the contrast for the pure tone component by 7.6 dB. Second order harmonic distortion in the dark zone is suppressed by 8.4 dB and third order harmonic distortion by 4.4 dB, compared to acoustic contrast control.

[1]  Philip J. B. Jackson,et al.  Planarity-based sound field optimization for multi-listener spatial audio , 2016 .

[2]  P. Jackson,et al.  Personal audio with a planar bright zone. , 2014, The Journal of the Acoustical Society of America.

[3]  A. Berkhout,et al.  Acoustic control by wave field synthesis , 1993 .

[4]  Yang-Hann Kim,et al.  Generation of an acoustically bright zone with an illuminated region using multiple sources. , 2002, The Journal of the Acoustical Society of America.

[5]  Jun Yang,et al.  Design of a time-domain acoustic contrast control for broadband input signals in personal audio systems , 2013, 2013 IEEE International Conference on Acoustics, Speech and Signal Processing.

[6]  Jordan Cheer,et al.  Robustness and Regularization of Personal Audio Systems , 2012, IEEE Transactions on Audio, Speech, and Language Processing.

[7]  Philip A. Nelson,et al.  A theoretical study of sound field reconstruction techniques , 2007 .

[8]  Filippo Maria Fazi,et al.  Comparison of Listener-Centric Sound Field Reproduction Methods in a Convex Optimization Framework , 2016 .

[9]  Daan H. M. Schellekens,et al.  Time domain acoustic contrast control implementation of sound zones for low-frequency input signals , 2016, 2016 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP).

[10]  Thushara D. Abhayapala,et al.  Personal Sound Zones: Delivering interface-free audio to multiple listeners , 2015, IEEE Signal Processing Magazine.

[11]  Lars G. Johansen,et al.  Assessing the Influence of Loudspeaker Driver Nonlinear Distortion on Personal Sound Zones , 2017 .

[12]  O. Kirkeby,et al.  Reproduction of plane wave sound fields , 1993 .

[13]  F. Jacobsen,et al.  Sound field planarity characterized by superdirective beamforming , 2013 .

[14]  Jan Abildgaard Pedersen,et al.  Impact of loudspeaker nonlinear distortion on personal sound zones. , 2018, The Journal of the Acoustical Society of America.

[15]  R. Rabenstein,et al.  The Theory of Wave Field Synthesis Revisited , 2008 .

[16]  Jordan Cheer,et al.  Design and Implementation of a Car Cabin Personal Audio System , 2013 .

[17]  Philip A. Nelson,et al.  Comparison of strategies for accurate reproduction of a target signal with compact arrays of loudspeakers for the generation of zones of private sound and silence , 2016 .

[18]  Jun Yang,et al.  Robust personal audio reproduction based on acoustic transfer function modelling , 2016 .

[19]  Archontis Politis,et al.  Sector-Based Parametric Sound Field Reproduction in the Spherical Harmonic Domain , 2015, IEEE Journal of Selected Topics in Signal Processing.