If you go with subs, you need at least two and preferably more to approach the in-room bass smoothness of the Maggies. Let me explain:
James M. Kates authored a study published in the Journal of the Audio Engineering Society that documented the superior in-room bass smoothness of a fullrange dipole loudspeaker, in comparison with a monopole speaker.
Todd Welti and Earl Geddes (who was my teacher) have established the superior in-room smoothness of multisub systems using three or four thoughtfully placed subs. Basically, multiple distributed bass sources result in significantly smoother in-room bass because their individual dissimilar in-room peak-and-dip patterns average out. This is not entirely unlike the case of having two dipole speakers, wherein each dipole can be modelled as two monopoles in opposite polarity separated by a path length. Two dipoles = four monopoles (two in reverse polarity); four subs = four monopoles (preferably spread apart).
In-room bass smoothness increases proportionally with the number of distributed bass sources. Thus two subs are twice as smooth as one. And four subs are twice as smooth as two. And two dipoles (approximately equivalent to four monopoles, distributed in polarity rather than in location) are about four times as smooth as one monopole sub. That's why most people who try a single sub with Maggies give up on it, and many if not most people who try two subs stick with them (I'm leaving out some details for the sake of simplicity).
In my experience four distributed subs do a very good job of matching the in-room bass smoothness of a pair of dipoles. Of course WAF is not high with a multisub system, so this approach may not be practical in this case, but it's good to be aware of the technique.
Remember, the purpose of going with multiple subs is quality, not quantity. Not only is the bass smoother, it is also more uniform throughout the room, which is nice for anyone not in the sweet spot. Smooth bass = subjectively fast, pitch-correct bass; not-smooth bass = boomy or one-note bass, as the peak or peaks stick out like sore thumbs, unless we turn the subs down until the peaks are subjecively unobtrusive, but now the rest of the bass spectrum is not fully represented. So smooth bass tends to be "fuller" bass because the level of the subs is not dictated by the sore-thumb peaks.
Duke
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