IMO, the discussions about bass are off the mark as to why smaller speakers sometimes sound "clearly, crisp[er], and more detailed."
The main reasons for that observation are, IMO, midrange pattern consistency and cabinet diffraction.
First, midrange pattern consistency. The IMO fatal flaw typical "high end" speaker (a 2-way with a ~7" midwoofer and a flush-mounted ~1" tweeter and a somewhere crossover between 2-3 kHz) is that the midrange pattern is not constant. Rather, it looks like a mushroom cloud: narrowing progressively as the woofer plays higher, and then blowing up wide open at the bottom of the tweeter's range. Compare the horizontal polar response of a very poorly designed big speaker:
(B&W N800 Diamond)
to the horizontal polar response of a very well designed big speaker:
A very small speaker (say, for instance, something along the size of an NHT Absolute Zero) keeps a fairly consistent (wide, but consistent) pattern, i.e more like the good Revel than the crappy B&W, because the mid doesn't play in its beaming range. The way to "fix" this problem in a larger 2-way is to use a waveguide to control the tweeter's pattern at the bottom of its range such that the tweeter's pattern down low matches the next driver down's pattern up high. That "waveguide" can be it a separate structure, such as in most of the Revel speakers and most studio monitors. The other way to do it is to concentrically mount the tweeter inside the woofer, and shape the cone to act as a waveguide, e.g. KEF Uni-Q, Tannoy Dual Concentric, and TAD/Pioneer CST.
Second, diffraction. Smaller speakers have smaller baffles, which pushes the diffraction effects higher. The way there to make a large speaker "sound small" is to design the baffle for lower diffraction, with curved surfaces and possibly surface treatments such as felt. (See, e.g., David Ralph's felt studies.
So, to summarize, the way to get a speaker with the SPL capability to play music at realistic levels AND the perceived clarity and deta of a small speaker is to control the tweeter's pattern at the bottom of its range, and minimize diffraction.
Originally Posted by arnyk
80 Hz crossovers are generally safe, that is they are less likely to produce problems with bass imaging. This goes down hill pretty fast as the crossover frequency goes up. At 100 Hz your options for positioning the subwoofer are getting narrower.
My experience differs. I expect it comes down to an "s," though: subwoofer vs. subwoofers
. With distributed subs around the room, I've not found imaging issues even with subwoofer lowpasses as high as 150Hz. (Any subwoofer I would use has extended smooth response well beyond 150Hz, so electrical highpass and acoustic highpass is the same thing.) Even with the mains highpassed at the same frequency (electrically, at least). At least, once various rattles were taken care of. The biggest enemy of non-localizable bass, IME, is sympathetic rattles...