can be found at www.selectproducts.com/calculators.html There are diagrams showing where c1, c2, etc go. The calculator lets you specify the Z of YOUR driver, at YOUR chosen crossover freq., in up to 3rd order configurations. Don't be lame and just input 16 ohms, MEASURE the things at 500Hz., or whatever. For the HF, you need to consider what Z the "Pi Pad" is letting the xover see. Sam