While progress has been made in design optimization of concentric ring electrodes maximizing the accuracy of the surface Laplacian estimation. it was based exclusively on the negligible dimensions model of the electrode. Recent proof of concept of the new finite dimensions model that adds the radius of the central disc and the widths of concentric rings to the previously included numb... https://www.roneverhart.com/Gretsch-G5210T-P90-Electromatic-Jet-Two-90-Single-Cut-Electric-Guitar-w-Bigsby-Mako-p23063/