@djones51 --
With active speakers and DSP box size and bass extension are being challenged in interesting ways. Look at the Develiat Phantoms down in subwoofer range with appossing drivers and a lot of watts.
The Phantom's to me are more an interesting development in what can be achieved from a very small sized speaker package than what's entirely successful in itself against speakers of larger volume; they may impress (some people) in the context of being very compact, but against larger sized main speakers and subs come off like they're working hard to sound bigger than they are. Going further into the high eff. realm with a comparison here only exacerbates this impression, which is to say: challenging physics in regards to size only gets you so far.
Quite a few other interesting active designs (like the Genelec "One's") have immerged challenging their passive iterations (if they exist as such as well) to come out victorious and at a favorable price, and that's something to cherish. These however are usually compact designs for smaller to moderate spaces, and don't escape the limitations of physics imposed on them. Fortunately active configuration can had with large, eff. speakers as a solution of separate components, but this does require some tech understanding (that can be learned) with DSP's and setting up cross-overs, if they aren't pre-configured.
@audiokinesis --
Now imo there are definitely some qualitative advantages to that higher efficiency, but in my experience the market for eight cubic foot speakers is rather limited.
Anyway my guess is that the higher costs and the box size penalties attached to high efficiency are the primary reason why low efficiency speakers dominate the marketplace.
What's particularly interesting with high eff. larger speakers, to me, is that simplicity can be maintained when incorporating horns or waveguides fitted to compression drivers, and thus avoid some of the complexity issues that face low(er) eff. larger speaker designs. A 2-way high eff. design can be had with fairly large woofer/mids crossed to a horn/waveguide with very nice power response in the XO-region, though needing subs augmentation. I use such a configuration myself, now awaiting new horns from ~700Hz on up with a mouth area of some 2 x 3 feet for controlled directivity, if needed, down to 500Hz for a smoother transition to the dual 15" drivers below; coherency is paramount, and in conjunction with high eff. and sheer size is an intoxicating trait.
Fortunately it's up to each individual to pursue the advantages afforded through high eff. and size, even if it isn't popular, and it mayn't be expensive.
