I will add, this all probably sounds like a pain the rear to simply hook-up a sub, but from what I have read, worth it when you get them set-up correctly. But....this set-up is more geared towards music, so the OP probably should not think the 2W will act as a HT subwoofer, but instead be more subtle in how it works.....with music.
I have two powered subs hooked-up to my 2CE Sigs, in stereo. But took a different approach (as I already had the subs) and have them connected directly via each R & L speaker terminals via cables not the amp, then set the crossover low and set the gain ‘to taste’ at the subs. As the powered sub amp is such a high impedance, no worry about the ohms falling too low as may happen with two daisy chained passive speakers. Not perfect, but works pretty well after much crossover/gain trial and error setting. It’s more a set-up for music, not HT sub results.
But to be honest, the 2C’s don’t really ‘need’ subs, as I know the Sig’s acoustic coupler goes down to 28hz, but it’s always nice to have a bit more musical grunt and low end, if not over done.
I have two powered subs hooked-up to my 2CE Sigs, in stereo. But took a different approach (as I already had the subs) and have them connected directly via each R & L speaker terminals via cables not the amp, then set the crossover low and set the gain ‘to taste’ at the subs. As the powered sub amp is such a high impedance, no worry about the ohms falling too low as may happen with two daisy chained passive speakers. Not perfect, but works pretty well after much crossover/gain trial and error setting. It’s more a set-up for music, not HT sub results.
But to be honest, the 2C’s don’t really ‘need’ subs, as I know the Sig’s acoustic coupler goes down to 28hz, but it’s always nice to have a bit more musical grunt and low end, if not over done.