Played with a speaker design decades ago using a 12" full range driver. It produced sound that was just OK. Since then have owned quite a number of multi-driver box speakers. Recently became interested in better understanding small wideband driver in an enclosure application. For example, put a 3, 4, or 5 inch wideband driver in an enclosure. Noticed claims of no crossover designs. Can you really run a small driver full range without at least a high pass filter? How could that size speaker survive below 100 HZ without distortion or failure?
They're designed to be -but that comes within several contexts, typically quality enclosure design to load the driver properly (remember its low-frequency free air / IB behaviour is not the same as its in-box characteristics), and also intended use. If you want to be cranking material at high levels with 20+dB dynamic headroom over your target average SPL, they're unlikely to be ideal. If you have somewhat more modest requirements
they can work fine.
Line arrays as noted above are another application; when you have 16 - 25 units per channel, you've opened up another field. Pulling a driver out of the air, take, say, Dayton's PC83-8. Single unit has rated IB sensitivity of 83.8dB 1m/2.83v and a thermal power handling of 30w. You put 25 of those in a series-parallel array (5 paralleled packs of 5 series-wired drivers), and you've suddenly got roughly the Sd of a 14in woofer per channel, just under 14dB of efficiency gain over the single driver, taking it to almost 97.8dB 1m/2.83v from Fb up to about 1.5KHz (above that, because the individul drivers won't sum at the listening position due to the different distances & phase angles, SPL will drop to roughly that of a single unit), and 750w nominal power-handling. Since you've got 25x 1in coils to dissipate heat rather than a single type, you're lowering thermal distortion too, and assuming it's an untapered floor-ceiling line you have the usual advantages of tightly controlled vertical directivity and reduced room interactions. With that behind you, you're free to employ your choice of analogue or digital EQ to boost the LF below Fb, and the HF above the point where the drivers are no longer summing. The latter takes very little additional power, since music power falls off rapidly above ~500Hz anyway, so even with a hefty boost, the array is just ticking over. The LF is a bit more challenging -the Dayton example here isn't ideal since it's only got about 2mm rated linear travel, but assuming a valid comparison to roughly equivalent systems, and remembering that with arrays, SPL drop-off is only -3dB per doubling of distance in the fresnel zone rather than the -6dB of a point source, you should be fine to 40Hz or so before severe compression sets in, unless you have much more demanding requirements in terms of LF dynamic range / headroom -in which case you'd be looking at a different sort of system in the first place.
None of which is to suggest arrays are some kind of ideal or panacea -they aren't, they have their own characteristics & issues too. But it gives an example of different types of operating conditions with drivers of this kind.
