For anybody alive, ADS gave specific instructions to me about 26 years ago for the L1590 and C-2000. Remove c38 and c39 (size about 6/16 x 7/16 x 2/16 inch, color redish brown, marked ".1k 50/100"). The cross over selector is set to prog. and the crossover program switches in the back are set so each switch (the little circular hole in each switch) is at the bottom position. Before the removal described, this configuration provides the 300 Hz crossover and 0.68 filter Q. There are 15 other combinations of switch settings possible. If this is relevant to you, I would appreciate your response