Suitable Low Frequency X-Over for B&W Matrix 804's

Hi there I am almost done modifying my 804's, I have really just given the drivers a once over and there in great condition as well as put mundorf supreme caps and a better resistor in the crossover. The cable inside is actually really good and built just for the Matrix series.

Any way the drivers use a linear suspension in a 2.5 way configuration. I am going to install a capacitor in between my RCA's and the input to act as a crossover as oppose to using a active crossover and adding another link in the chain. So I am not using a passive subsonic filter for reference.

Thanks a million
Oh this is just for music, Ill throw a movie on now and again but theater isnt a concern for me
I just saw your ad, I like your style. I was trying to find a Highpass signal that made me feel like I wasnt going to destroy my speakers from playing loud. I never did but it sure looked like it wasnt good