As Dave suggested, a Graz XLM ribbon will dramatically improve the sound. Also, I have changed the woofer in my Centaurus Minor, and that is better, too, and requires no crossover modification.
Go to the Apogee user's group and do a search, the info you need should be there somewhere, or ask.
http://audioworld.com/cgi-bin/sw/forumdisplay.cgi?action=topics&forum=Apogee+Acoustics+Users+Group&number=1
Go to the Apogee user's group and do a search, the info you need should be there somewhere, or ask.
http://audioworld.com/cgi-bin/sw/forumdisplay.cgi?action=topics&forum=Apogee+Acoustics+Users+Group&number=1