Hy. Wayne . So partsexprees sell the Dayton 10 W non inductive resistors .So I need to group four I ohm 10 W value part ( 004-1) in serie to get the 4 ohm 40 W required in the woofer section of the 8 Pi . Does work the serie -parallel to found the right value of the resistor as in the speaker impedance chart .Thanks