IIRC, Danny designed the X-over for them for that speaker. At least, a few reviews said that, I never actually asked him. Try the Skiing Ninja, as he used to be very active on the AV123 forums and offered various upgrades for their speakers (he has recently taken his site down, but email still active). He may be able to at least point you in the right direction
sean@skiingninja.com
Worst case, I'd look for another pair for sale so you have some spares or start looking for new speakers
