Hi,
is it a crossover you need or a pair of matched Low Pass and High Pass filters?
search for Ti.com
AAJ slyt306
Ti also have a large number of papers (application notes) on designing and building and correcting for errors of the various filter types.
Burr Brown also have software filter2 (S&K and MFB) and filter42 (state variable) that work well.
Try Linkwitz web site.