Active Crossover Recommendations

the cap would of course go in series w/ the high freq amp, while the low freq amp (the sub) you could simply rely on its own internal crossover to filter out higher freq info

For hi pass, cap in series, correct.

Matching the two xovers, however, may take some experimentation: if the sub's xover is not 1st order (6dB/octave) electrical -- which it probably isn't -- you may just get away with playing w/ the low pass frequency. This worked for me once, where the powered woofers part of the speaker system was detachable from the rest of the speaker; the cut off for the woof (12dB/electrical) was set ~1 octave lower than the main; then we used placement of powered woofs to compensate for the phase differences between the two.

Energy makes a nice subcrossover.I have one if your interested was going to list fri.I liked these much so far have bought 3 over the years much better than paradigm x30 its very useful and well built.

Linkoping:

I disagree with your blanket statement about the Marchand xovers. I am using the XM126 in my system with excellent results. Additionally, the company provides very good support for its products. The Marchand tube xovers are excellent performers at a reasonable price. Check my review of the XM126 at the url below:

http://forum.audiogon.com/cgi-bin/fr.pl?rprea&1126709059&openusid&zzGmorris&4&5#Gmorris

Accuphase F-25 active xover