Why are high efficiency speakers preferred for low volume listening?

I am curious about this myself. I have KEF Reference One’s, which are not efficient, and years ago I had Klipsch Heresy’s, which are very efficient. Is it that high efficiency speakers are more “lively”, or was that just the horns on the Klipsch doing that? If I were to upgrade my speakers, I would probably look for something a bit more lively. 

@zlone  , so is the bottom line that you liked the Klipschs better than the KEFs, particularly at low levels?

In my experience driving low efficiency speakers with milliwatts they will sound anemic at low volume; high efficiency speakers can play well with milliwatts and not sound anemic at low volume. Also amplifiers, tube amplifiers for sure, produce more distortion in lower impedances then higher impedances.

Thank you, @ditusa  ,  I can get my head around that.  But I am assuming it is how easy the speaker actually is to drive (and this would be due to its nominal impedance?) versus the number/sensitivity the speaker is rated at?

I doubt that high efficiency speakers and good low level detail are absolutes. It’s likely more important that things like the amp being a good match to drive the speaker impedance, the system has good resolution, and that phase coherency and overall clarity of the speakers are excellent, along with a suitable room acoustics, etc...all are still significant factors regardless of the speaker efficiency.

Audio is complex, and it’s rarely as simple as isolating one parameter and calling it good. There are always good and bad examples and pros and cons with every principle you can name, and every choice you can make.

Thanks for the feed back to my question, @knotscott  .

I would never buy a speaker with a sensitivity level below 92db.  Please pardon my lack of knowledge and inexperience as a technician, but lower sensitivity speakers, at least in my  experience requires the amp to bring them to life. Oftentimes I have found this to sound lifeless , requiring me to jack up the amp to breathe some energy to the presentation.

Thank you also, @judsauce  , for your feedback.

Easy to drive speakers avoid low impedance and phase shifts at all frequencies and require an amp work less hard in general be it at low or higher volumes. So that is advantageous. They will also tend to sound more similar with various amps.

 

Whereas high efficiency speakers simply produce higher spl overall per watt. The advantage there is mainly going louder with a less beefy amp.

@mapman  , so are you saying it is the way that the speaker handles low impedance versus it's sensitivity rating?  Although I would think that at low levels the impedance of a speaker would remain relatively stable and not dip?  

So is the bottom line that you liked the Klipschs better than the KEFs, particularly at low levels?

No, definitely not. For the time they were great, but I love the KEF’s, even for low volume. I just wonder if another speaker might be a little more lively at lower volumes.