Low-sensitivity speakers — What's special about them?

Thanks, unsound. That helps me make a bit more sense of the measurement which the page for the speakers I ordered list. I bought them for the reputation and reviews --and the notion they'd be sized well for my listening room, which was confirmed by the maker. It was only later on that I realized the sensitivity was low. Here are the stats/landing page for that speaker. http://www.salksound.com/model.php?model=WOW1

@timlub --

What it comes down to is... really good mids with any type of top end extension without cone break up is hard to find in true high sensitivity speakers.

Perceived really good mids and upper range extension (i.e.: "any type of top end extension" leaves room for quite a lot) is readily available with true high sensitivity speakers - without necessarily requiring exotic cone materials. Being so I gather cone break-up, in whatever shape it may present itself (or not), isn't an issue. 

@unsound --

One will be hard pressed to find high sensitivity speakers that can produce respectable step response or square wave response.

Question is whether it holds significant correlation in regards to perceived sound quality, not least depending on who you're asking. There's hardly consensus here, but transient behavior in (time aligned) all-horn set-ups, representing the best efficiency, are hardly the ones to fault the most in this regard. Even so, relevance/correlation is required. 

There's a lot more to speakers than sensitivity alone.

Sure, but I'll definitely side with poster @alexberger's above posts on the significance of high sensitivity (and headroom) as an aspect highly overlooked by the audiophile community at large, and that it's an essential ingredient in achieving a live sound imprinting. Those who've heard a well-implemented all-horn system covering most of the audible range will know this kind of sonic ignition, scale, presence and ease simply doesn't exist in low to moderately sensitive speakers; they just sound restrained and malnourished by comparison, not that they can't be highly capable in other areas. Yes, high efficiency and full-range requires BIG size, but you want to eat your cake too that's the pill to swallow. Personally I find it's definitely worth it. 

That aspect @phusis "a live sound imprinting" is significant. Thanks for putting it that way. Another, good metric to judge speakers by; very useful.

@phusis 
So you say "Percieved" and that these mid and bass drivers with good extension and little cone break up are readily available.... recently I've shopped a few hundred drivers looking for such.  Please list the model numbers.  

@timlub --

So you say "Percieved" and that these mid and bass drivers with good extension and little cone break up are readily available.... recently I’ve shopped a few hundred drivers looking for such. Please list the model numbers.

Perhaps we’re addressing this matter differently by now. Initially you wrote "really good mids with any type of top end extension without cone break up is hard to find in true high sensitivity speakers," so I set out to express my impressions from a complete speaker system - not focus on a single driver. Cone break-ups can be more or less challenging depending on your design goal and overall requirements, and nothing yet has been specified into the nature of a given design to illuminate your context.

Where "true high sensitivity" goes horns seem to be dictated, and with midrange compression drivers I’d wager their upper range (clean) extension isn’t a bigger issue, if as much as their lower end limitation in a given horn. Knowing what one is dealing with here would dictate what to work around rather than against, and with horns in particular it’s not exceeding the bandwidth of each horn element to main good power response etc., so a full-range all-horn system would typically require a 4 or 5-way approach.

With true high sensitivity speakers an excellent midrange can be had via a range of designs, so why would cone break-ups be a particular issue here if the design accommodates inherent challenges? You’re addressing and calls for the existence of specific midrange (and now bass) drivers with good extension, so what’s your context, specific use and related issue?