Hi kgantzer, I can share a little of my experience with you.
First off, there are very few speakers/cabs that can really handle 31 Hz with any authority. Down in that part of the spectrum, we're really talking about very powerful subwoofers, something along the lines of EVX-180A's in a folded horn cab (in other words, think big and heavy)! When we do outdoor rock gigs, I use a pair of EVX-180A's fed with 2100 watts each (Stewart 2.1's). And sometimes that's barely enough.
But, the key concept is "that's my sound". In other words, I like my audience to feel that deep thunderous bottom end, that you can't really "hear", but that crawls up your legs and loosens your bowels, and makes your pant legs vibrate at fifty yards. Getting that kind of bottom end "out there" into the audience requires huge amounts of power, and very heavy equipment. It's true that one can occasionally get some assistance from the PA and so on, but that doesn't eliminate the need for gear that can handle a good strong fundamental.
The flip side of the coin, though, is that most people don't really require that sound. The ear (and brain) do amazing things with low frequency sound, for instance there's a "completion phenomenon" that occurs when you have a signal rich in harmonics but devoid of a strong fundamental. You still "hear" the fundamental, even though it's not really there (your ear kind of "fills in" the missing part of the spectrum). Also, there are many playing styles (like slapping, for funk and fusion) where the midrange is just as important as the low frequency fundamental, if not more so. In fact, sometimes the presence of a strong fundamental makes the sound "muddy", and it's possible that you might get a better sound (overall) without the mud.
Also, there are very few speakers that will handle a strong 31 Hz signal. I wouldn't even dream of trying it with 10" speaker cones, they'd try to jump right out of their frames. When I'm playing a bass that has an especially strong fundamental (like Alembic's for instance), sometimes I have to EQ down everything below 50 Hz just to save my speakers. That's where "clean headroom" is meaningful, those low frequency transients really suck up the power, and generally speaking they'll put extreme stress on your speakers. Also, if you have an amp and speakers that will handle the ultra low frequencies, you have to watch out for "sub-sonic" transients, like when you slap the B string you can get stuff that's way below 31 Hz, and if your amp and speakers try to reproduce that, it can be big trouble for your rig.
If you really need those low frequencies, there's no way to avoid "big" speakers, and a "big" amp. That's just physics. There's absolutely no way a 10" speaker is going to deliver 31 Hz with any authority. You have to go with 18's, or "lots" of 15's, or something like that.
Over the years, I've learned a few things. One is, I'm getting too old to be hauling around big subs. My back isn't what it used to be, and I rarely have the benefit of a team of roadies these days. The other thing is, that it's possible to get an authoritative and nicely balanced sound without going overboard on the low frequency fundamentals. And, most of the time, it's not "necessary" to use those 31 Hz signals, except in rare circumstances. For indoor gigs, like most ordinary club gigs, the shape of the room and the geometry of its components is typically highly variable, and I don't usually have time to set up the EQ "correctly" for the room. Most rooms have all kinds of odd low frequency resonances, and sometimes even the stage itself can be "boomy". In those situations, I find it far more useful ("operational") to go with the balanced midrangey sound, rather than going through all the time and trouble to set up a thunderous low frequency extravaganza.
So, just a couple of tidbits to consider. All IMO of course (and IME).
