I think you're looking at it wrong. At this point you should be more concerned with the impedances the Maggies are going to present to a tube amp. If Maggies are in future, Warrenh is right, check them out with current amp & set-up so you have a better idea of what's what.
Maggies put out as much sound out to rear as front, so be cautious with regard to placement.
Also,a sub might not be up to the challenge of the Maggie's fast midrange & treble.
Maggies put out as much sound out to rear as front, so be cautious with regard to placement.
Also,a sub might not be up to the challenge of the Maggie's fast midrange & treble.