My first, and only, reaction would concern sensitivity. I remember the DQ-10 as being incredibly inefficient and a huge power sponge. My guess is that you'll need to try to match the original woofer's sensitivity if you want to maintain the same 'balance' across the spectrum. Just sayin' ...
I'm guessing there's more than sensitivity since J Dahlquist crossovers were not out of the Philips book so to speak. I have spare Advent woofers but why not upgrade?
You're right ... I'm sure they were complex, though I'd guess that the low pass for the woofer would be less involved than the pass bands for the mids.
