This paper proposes a new smoothly clipped absolute deviation (SCAD) regularized recursive subspace model identification algorithm with square root(SR) extended instrumental variable (EIV) and locally optimal variable forgetting factor (LOFF). The proposed algorithm is based on a new local polynomial modeling (LPM)-based variable FF EIV projection approximation subspace tracking (PAST... https://www.roneverhart.com/Gretsch-G5210T-P90-Electromatic-Jet-Two-90-Single-Cut-Electric-Guitar-w-Bigsby-Mako-p23063/