Cello Grand Master- go active?

Krell probably makes, by custom order, the best electronic crossover out there. I would contact them, as they may have that info.

Other possible sources for info would be either Viola.com (same engineers), Mathew James (have use of the Cello name and repairs them), and lastly, Red Rose Music (for Mark Levinson's opinion).

My non-Cello system is actively biamped, but I would do a lot of research before actively biamping the Cello's. I have heard the Big Cello speakers at Marks place many times and did love them. They were always driven by bridged Performance amp. If actively biamping them would have been a good idea, Mark could have easily done that since he had the number of amps available. I have never heard of anyone ever trying what you suggest. ... But it is a great idea.

Richard
PS> Actively biamping my speakers was the single, best (all be it, the most expensive) upgrade that I ever made.

There is no doubt that going active would yield imporvements; plus, you already have adequate amplification to actively biamp the spkrs.
However, in order to do so, you need the EXACT specs of the xover i.e. the schematics.

Anyone you can contact? If not, you'll have to find s/one to back engineer it.
Meanwhile, do try googling the things, maybe you'll come up with s/thing.
Lastly, don't neglect to post at the Madisound board, there are many xover specialists lurking there. Good luck