How do you run your system with a powered, or non-powered sub? I have an SWR SM-400s and Henry the 8x8. I won't sell the 8x8 if I can find a way to generate the heavier lows when I need them, which the 8x8 can't really do by itself. Not what I'm calling for anyway. The SM-400s may not be able to put out enough power run stereo, so a powered sub would be ideal I think. Don't want another head, I like the sound of this one. I'd like to run the SM-400s in 'Mono' to the Henry, and use the Send to get line signal to the sub. Info, anyone? All ears here, thanks.