Subwoofer Connection

Guys, let me know if I am way off base. I would like to hook a powered subwoofer to two different systems. One system output to the left input on the subwoofer and the other system to the right input of the subwoofer. Of course the separate systems would never be powered at the same time.
Might work.

I was told that it would note work to connect to both high level and line level inputs to my Velodyne dd-18 from 2 systems and it worked fine.

If not, I have a Niles auto-sensig switch I now don't need :)
I have an SMS-1 Velodyne controlling my subwoofer. It has two RCA inputs. I use one for the LFE ouput from my pre-pro and the other to my 2 channel preamp. No problems unless you put a Y adapter on the two preamp outputs.