Spatial Fourier transform-based localized sound zone generation methods with loudspeaker arrays

This presentation provides spatial Fourier transform-based localized sound zone generation methods with multiple loudspeakers. First, these approaches are compared with conventional acoustic contrast and pressure matching approaches which are based on the least squares (LS) solution. Whereas these LS-based methods are unstable and some regularization schemes are required because the acoustic inverse problem is very ill-conditioned, the proposed spatial Fourier transform-based approaches can directly derive stable driving functions of loudspeakers without regularizations since the propagation and evanescent components of sound fields can be separated and only the propagation components are introduced to the driving functions. Then, spatial Fourier transform-based multiple sound zone generation methods with linear and circular loudspeaker arrays are introduced. In these approaches, the sound pressures on a line or a circle are modeled as rectangular or Hann windows, and the driving functions are analytically derived from the spatial Fourier transform. Additionally, localized sound zone generation approaches with linear, circular, and spherical loudspeaker arrays are introduced. In these approaches, the sound pressures produced by a loudspeaker are cancelled by the linear, circular, and spherical loudspeaker arrays. These driving functions are also derived from the spatial Fourier transform. Challenges and prospects of these approaches are finally described.