In audiophilia in general, certainly since the 50’s or so, it appears speaker size (and this naturally includes subs) is more or less everything - that is, the want for limiting size led on by the need for convenience, spousal demands and interior decoration. It’s as well a convenient (and false) argument that "speed" is supposed be an issue with larger diameter drivers; if anything speed is not the proper descriptor here, but transient ability and group delay are relevant factors with bass reproduction, so is headroom/ease (and, ultimately, efficiency), whether a driver is direct radiating or hidden inside the enclosure, whether there’s impedance matching between the driver and the air to which it loads (via an acoustic transformer; a horn), whether the mains are high-passed, tuning frequency, and so on.
(re: @millercarbon) I disagree with the notion that time-of-arrival (and symmetry with the mains) doesn’t matter with low bass reproduction with subs in the mix, as well as the disregard for the importance of similar design principles when integrating subs with mains. Certainly all-horn main speakers benefit from being coupled to horn subs in some iteration when compared to being augmented by direct radiator subs, for a variety of reasons really, but notably the horn-loading of a bass driver creates a different feel of the low frequencies that’s typically somewhat smoother, more refined, dynamic, air-shaking/floating, and present/enveloping (people would know this if they knew what horn bass sounds like, but few does). I won’t argue the overall benefit of multiple subs, benefits that are, but this approach is not going to sonically alleviate different sub topologies; bass is not just bass that sees its unifying "redemption" in coverage alone. The ’dissipated energy in relation to modal behavior’ argument is compelling within a given bass principle.
Big subs, not least in pairs or more, are impractical, ergo they’re undesirable for many an audiophile for whom practical considerations like the above mentioned weigh in. Home audio reproduction therefore often, if not mostly finds its outset in "function follows form" (and not, what it rightfully should, the other way round), leaving us nonetheless pestered with claims about how smaller bass drivers are "faster," the virtues of narrow baffles, small speakers for small(er) rooms, etc. This is also constitutive of an audiophile mentality that ridicules or even detests subs (or mains) that are capable of delivering sonics with brute force down to 20Hz or deeper, typically signified via their large size and occasional use of pro drivers, that supposedly makes them sound less refined or whatever.
(re: @Elizabeth ) My take on the general goal of audiophiles is that their endeavor is typically less about "realism" than cultivation, but the cultivation of what? This is up to each individual, it seems, within the practical provisos mentioned above. I’d wager realism would dictate size not being a constraint, nor frequency extension, ease, SPL-capabilities, dynamics, etc. Trying to reproduce organ concerts at home anywhere near what is remotely realistic, indeed one of the absolute most trying challenges of any hifi-setup, is not only about frequency extension (as your recommendation of a "big sub" would point to), but about scale, size, image stability, impact, spatial acuity, etc.; nothing less than big will do here.
