Wow, lots of good advise here. I have the spicaspeakers site and thought I should weigh in. Ponnie and John B are friends and can be a big help.
Suggestions:
1) If you alter the coils (to air coils) you will alter the time alignment, which is in my opinion is key to the character of these speakers.
2) The coils didn't change with the services code. The service code was done to adjust the crossover to match the peak characteristics of the woofer and to remove a hump in the freq. response (not the actaual crossover points). To accomplish this only a couple(?) of caps and resistor (or two) was altered. The schematics are on my site.
Suggestions:
1) If you alter the coils (to air coils) you will alter the time alignment, which is in my opinion is key to the character of these speakers.
2) The coils didn't change with the services code. The service code was done to adjust the crossover to match the peak characteristics of the woofer and to remove a hump in the freq. response (not the actaual crossover points). To accomplish this only a couple(?) of caps and resistor (or two) was altered. The schematics are on my site.