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

Generation of Private Sound With a Circular Loudspeaker Array and the Weighted Pressure Matching Method

“…We set a frequency independent value of p B,min , p B,min dB = −3 dB (for the QCS and the Hybrid Scenarios), and δ ψ = 10 −3 (see Section III-A). The WPMM weight ψ G in the low-priority zone was chosen as ψ G = 10 −2 , that is two order of magnitude lower than the maximum value of ψ G , i.e., ψ G = 1 [9], [12]. [28].…”

“…However, for a given array configuration and a given wavelength, a target field of this kind may be difficult to be reproduced especially if the bright point and the dark zone are adjacent to each other [11]. Previous works reported that arrays driven with input signals designed with the PMM may suffer of limited ability to preserve the characteristics of the spectrum of the original audio material to be delivered to the listener [12], [10]. This may be related to the fact that the transfer functions between bright and dark points are similar at low frequencies [8], where the size of the array is small compared to the wavelength.…”

“…More generally, a performance trade-off exists between directivity performance, input energy required by the array to perform directional sound radiation, and accuracy of reproduction of the target field in the listening area [18], [12], [23], [24], hereafter succinctly referred to as "quality". For example, for a given level of the input energy, a given system may be able to provide high directivity performance at the expense of a reduced quality in the listening zone [9], [10], [12].…”

“…For example, for a given level of the input energy, a given system may be able to provide high directivity performance at the expense of a reduced quality in the listening zone [9], [10], [12]. A number of PMM-based methods were proposed to control the performance trade-off by means of 1) parameters that are freely customizable by the users [13], [9], [12] or, 2) by calculating the input signals that satisfy given performance constraints [14], [15].…”

“…For example, for a given level of the input energy, a given system may be able to provide high directivity performance at the expense of a reduced quality in the listening zone [9], [10], [12]. A number of PMM-based methods were proposed to control the performance trade-off by means of 1) parameters that are freely customizable by the users [13], [9], [12] or, 2) by calculating the input signals that satisfy given performance constraints [14], [15]. Some of these methods are based on the WPMM [13], [9], [14], [12], a generalized formulation of the PMM wherein the so-called WPMM weights are assigned to the control points where sound is to be controlled with the aim of prioritizing (or not prioritizing) accurate reproduction of the target field at given control points [14], [9].…”