This post has great links to help people who are looking to make there own crossovers/filters for their car stereo speakers.

The first two links describe how to build different type of crossovers/filters.
http://www.the12volt.com/caraudio/cross.asp
http://www.mtxaudio.com/caraudio/edu...ersFilters.cfm
The next link will help you determine the coils and/or capacitors you need to make your crossovers/filters.
http://www.the12volt.com/caraudio/crosscalc.asp
Here is a link about Ohm's Law.
http://www.the12volt.com/ohm/ohmslaw.asp

I hope this helps anyone who wants to make a crossover/filter.

Mods if you think this is worth copying to the Extremely Useful Topics please do so.

Matthew