if so, yeah, i've been running them in zaph's taller box design for about a year now. they are being powered by my pc speaker system (they took the place of the fronts in a cambridge soundworks 4.1 setup). i would not doubt that there's some sort of crossover/filter setup built into the speaker system, but they sound great the way they are now. built a 5.1 setup for my parents w/o a notch and they sound very good (also a different enclosure design). my next setup is a 6.1 B3S setup using cyburg needle enclosures for the fronts. we'll see how that goes.
Why not using the player's EQ instead of filtering? I have measured my Itrigue 3400 with mic at listening position and compensated it with the winamp - media player eq. They sounded much better. Since you know what your speakers need from Zaphs before-after notch FR charts just eq them and avoid the notch. You will gain dynamics and save components out of signal's way.
yet again my project stalled, just finished uni and have been spending all my money on alcohol and petrol (not consumed at same time ) and Im waiting for the doller to drop again before I order anything.
All the parts can be found here http://www.madisound.com I think they now have online ordering and they are quite cheap too, im going to order some other XO parts as well for Zaphs audax mini speakers (remember everyone buying that AP100Z0 from maplin last year? well I have to do something with the 8 that I bought!!! )