Active Subwoofer Crossover

So in theory, a external electronic crossover provides more flexibility and should allow a more seamless integration of the mains with the subwoofer? Does the external crossover take the place of the preamp or is everything still controlled via the preamp?

I added the CR-1 to my system. I tried the suggested 80 hertz crossover point and it was too lean. I've changed the crossover to 45 hertz and like the overall sound better. The biggest impact in my system is an overall cleaner/ more detailed sound with added space/air...so much so that I'm trying to adjust to what I'm hearing.

I thought setting the crossover to 80 hertz was considered optimal? How do you establish the correct phase?

Thanks for the response. I don't have subs anymore and I sold my Aerial 7Ts. 

I'm getting Monitor Audio PL-500 and hope I don't feel the need for subs. 

I received my Monitor Audio PL500s and I'm so excited that I don't "need" subs. Yes, subs made a difference with my Aerial 7Ts, but there is something about a "full range" speaker in a relatively big room that a smaller speaker with subs just can't duplicate. I have so much respect for the Aerial 7Ts, but I realize my room is just to big for them.