Subwoofer for LFD NCSE suggestions

Has anyone with an LFD NCSE hooked up a subwoofer? If yes, what did you use, how did you work around the lack of a preamp out, and how did your system sound afterwards? Thanks for any responses.
Many powered subwoofers are equipped with high level (speaker cable) inputs / outputs which puts the subwoofer in between the LFD and your main speakers.

I'm using an LFD MK 3 with Rel Strata 3. The Rel attaches directly to speaker outputs on LFD. Mains are Audio Note AN/Ks w/silver wire. It's a great system, and I've had 3 pc "satellite" systems that cost much more.