Why are high efficiency speakers preferred for low volume listening?

I’m not the best one to address this but what is your budget? I just start here because the qualities you listed could lead to a $3000 system or much higher. You get what you pay for generally speaking.

Actually, @bjesien  , I am currently about halfway into the audition period that MD allows (on a pair of Revels that have a sensitivity rating of 86).  I decided to get off the fence and quit window shopping because the price was right (3k which was 1400 off msrp as they were b stock).  Besides the price being right, I finally made the move because the reviews suggested that even though the sensitivity is listed as 86, they "are eay to drive" (I don't seem to be having a problem in 50 wpc triode mode, and I have yet to experiment with the 100 wpc ultralinear mode) and that they are not finicky as far as placement.But I continue to read posts in the speaker forum, and often some one asks about speaker suggestions for low level listening, and often someone or more than one suggests a high efficiency speaker.  I am sure that there is a reason for this.  However, I understood that speakers that were rated at a high sensitivity were easy to drive with low wpc amps and would play loud with those amps, so I was thinking that if one was low level listening with an adequate amp, the sensitivity wouldn't be that critical.

At the time I decided upon these speakers, there were also a couple of Klipsch speakers rated at 99 for about the same price.  Since I am listening in a small room, I am not cranking it way up, and now I am wondering if I would be happier going that way.  As I typed previously, I still have almost 30 days to change my mind.  

And that was what generated that question, @bjesien  .

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?