In order to make a custom crossover you need to have the FRD and ZMA files. Now there are many ways to go about attaining those files, but it is not always easy to find them. In fact some companies only give you the information you need in a PDF file with no easy way to extract the data. Or at least, not until now.
FPGraphTracer has become one of my favorite free programs. In the past, i used SPL copy, which worked, but you had to manually trace the line if the program could not find it. You also had to pay close attention to see if it was tracing it correctly. Well that was not only a pain, but could take over 10 minutes to get a good trace. It was not very efficient or user friendly. FPGraph tracer is the exact opposite.
The program is simple and easy to use. All you need to do is set the limits on the left hand side. Once set, click on what you want to trace. A pink line will show up, if it is not perfectly align just adjust the part that is misaligned, but clicking on the graph (the place where the line should be). The pick line should then align.
Once you have everything aligned, just click save File – Save Data.
Then select the file type to save as. Impedance files are saved as ZMA and frequency response files are saved as FRD.