Should hook I speaker level sub to center or sides


I have 2 Avantgarde Duo woofers that I don't use since I built basshorns. I want to hook them up as subs to my theater but not sure if they should be hooked to the center channel in mono or to the front sides.

Can't use line level sub out as the speakers don't have a line in.

I'm thinking mono to the center but not sure. I know,, try it, but easier just to ask

thanks
herman
I suppose the best option would be to get another amplifier and use the sub line out.

Amen to that.
I've tried it both ways and there is plenty of bass in both the center and sides. Now the question is which is more accurate. No idea since this is new to me and I have no reference. Next I'll try one hooked to the center and the other to one of the sides assuming both sides get similar bass.

I suppose the best option would be to get another amplifier and use the sub line out.
I don't think that the center channel has much LF information. It's primarily dialog. I'd run them as subs to the main L/R speakers. That's assuming that you already have a sub for the LFE channel in your theater. In not, I'd get an amp to drive one or both of them off the LFE line level out from your AVR or processor.
I always have a quality sub connected in parallel with my center channel. But, two of those, wow? There's a huge amount of deep bass and impact from the center speaker most folks never hear.