Thanks everyone for the advice, and based on the overwhelming preference for 2 subs, I'm going to go that route and add 2 ML Depth i's.
Next question... The Depth i has both line-level and speaker-level inputs. Thoughts on one vs. the other for connecting 2 subs in a 2-channel system?
Next question... The Depth i has both line-level and speaker-level inputs. Thoughts on one vs. the other for connecting 2 subs in a 2-channel system?