There are a number of highly respected companies like Harbeth, Dynaudio, etc. who make relatively low efficiency speakers. It has been suggested on this forum that the only reason for this is to cut cost. I beg to differ. The sound characteristics of a speaker from Harbeth, as an example, is the result of very careful and meticulous selection of material, voicing decisions, and a number of other factors that have won them a loyal following (you can add me to that group). I seriously doubt that the 'only' reason for lower efficiency is cost. You can make the same argument for a number of highly respected speaker manufacturers.

I'm not sure why it's so difficult for some to understand that higher efficiency speakers do present tradeoffs, like just everything else in audio. Believe me, I would love to save some coin by buying high efficiency speakers and mate them with cheaper, flea watt amps. But I have yet to meet a high efficiency speaker that connected with me emotionally.

@fuzztone -- thank you for posting the video link. Whether you agree with it or not, the first comment below the video is by far the best explanation, and much more credible than 'oh, it's only a cost saving measure.' We should be grateful that we have so many choices that help us connect with our music in a way that makes sense to us, regardless of the underlying designs.
@oldhvymec 
[My terminology may not be the as eloquent as the word salad connoisseurs]

I think you're being too humble. I, for one, enjoy reading your posts. You have a way with words and a narrative style that's quite eloquent and a breath of fresh air. 

The sound characteristics of a speaker from Harbeth, as an example, is the result of very careful and meticulous selection of material, voicing decisions, and a number of other factors that have won them a loyal following
It is just marketing terms:) If you look to some pro audio drivers,they are better built,don't have plastic baskets as harbeths and cheap highs
Actually I had harbeth and dynaudio speakers.Harbeth speakers are limited sounding speakers.With some music (few or one instrument or solo vocals)I loved it.Try listen louder them or in free space ,outside house and their sound is very strange.Dynaudio wins here.Full range sound.They can rock here,but they are not dynamic as high efficiency speakers
Big efficient drivers makes midrange sound massive with visceral impact of instruments,some may refer them as shouty.
[ ... Dynaudio wins here. ..']

Sorry I didn't realize we were having a competition here :) I love Dynaudio, by the way, amazing speakers! I just happen to prefer Harbeth.

You missed my point by a country mile. There are a number of highly respected designers who are going for a specific sound signature. To dismiss the design (low efficiency) as merely a byproduct of cost savings is shortsighted. Harbeth has thousands of loyals fans ... as does Dynaudio, and Klipsch, and [insert your favorite speaker brand here]. The point being some people prefer low efficiency designs over high efficiency ones, and vice versa. 

[ ... Try listen louder them or in free space ,outside house and their sound is very strange. ...]

I have no intention of installing my speakers in a public park, so that's a moot point as far as I'm concerned :)
“I have yet to meet a high efficiency speaker that connected with me emotionally.”

@arafiq
Come over and listen to my Tannoy Canterbury’s next time you visit Houston.