I miss my Paradigm Reference Active 20s. The actives had a bit more lower frequency energy, but useful to about 40-45Hz. However, once I employed (two) 10" active subs (Rocket UFW10), and switched to the high pass filter they really opened up.
I'd recommend a good 10" sub, as I think the faster speed is a better match than the larger drivers. If I were buying today I'd probably try the Emotiva X-Ref 10.