Determination of black hole spin for several cases of doubled resonances. The functions , v ∈  { θ,K } are drawn for the frequency ratios n:m = 5:4 (black solid line), 4:3 (black dashed line), 3:2 (black dotted line), 5:3 (red solid line), 2:1 (red dashed line), 5:2 (red dotted line), 3:1 (blue solid line), 4:1 (blue dashed line), 5:1 (blue dotted line). Black thick line in T33, T44, and B33 represents ν_v = ν_v(a,x_ms), which denotes the frequency on the marginally stable orbit. Here we show how to determine the “magic” spin a_m = 0.983 in the case of a) “mixed identity” M13 with ν_θ:ν_r = 2:1 and ν_K:ν_θ = 3:2 giving the triple frequency set and b) “top identity” T34 with ν_K:ν_θ = 3:2 and giving the triple frequency set .