Why are high efficiency speakers preferred for low volume listening?

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. 

Thank you for clarifying that, @zlone  .  (And a quick google showed that your KEFs are rated at 85.)

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?  

@elliottbnewcombjr  , so are you basically saying that the bottom line is that horn (tweeters?)  sound better when played at low levels than traditional cone (tweeters/) do?  Sorry if it is obvious that this is what you said, but I am not good with this stuff, and I often have trouble wrapping my head around it.

consider that highly efficient speakers are likely to involve horns,

the throat/directivity of horns give dispersion control cones do not.

i.e. smooth ’received’ frequency response curve at the listening position (not just 1 meter away), the different relationship of direct primary and reflected sound waves

the perception of any frequency, and clarity of instantaneous peaks is/are enhanced when less reflected sound waves are involved.

dispersion, not volume

@audiokinesis  , thank you for oversimplifying.  That helps.  

@james633  , thank you for the feedback on this.  I think I am getting the picture.  High efficiency doesn't take as much power to move and at lower levels not as much power is being provided to the speaker as at higher levels.  

@elliottbnewcombjr  , I am actually not the one with the KEFs, that was @zlone  .  I am trying out a pair of Revel M126Be's.  I like them so far, but after reading posts here in the speaker forum, I am questioning myself as to whether a higher sensitivity speaker would have been a better coice in the small room I listen in.  My amp does not seem (to me) to be straining in 50 wpc.  I know your opinion of triode versus ultralinear, and today I put another 5.5+ hours on them, and for the last couple of hours I went to 100 wpc ultralinear and I felt that female vocals took on a bit of an edge in that mode.  I guess the final proof (or close to final) will come in about 20 more listening hours when I follow @soix  's advice and hook up my old speakers and see how I feel about the difference.  As always, I appreciate your feedback.  It is always welcome. 

Thank you for the input, @atmasphere ; the speakers that I am auditioning (and that I have about 3 more weeks on that audition) have an sensitivity rating of 86, a nominal impedance of 8 ohms, and according to Erin’s Corner a minimal impedance of 4.69 ohms. One of the reasons I decided to give them a whirl was that the reviews said (despite the sensitivity rating)  "easy to drive" and although I do not completely trust reviews, I don’t see why they would lie about that.

Anyway, I don’t feel that my amp (Cary V12) has been straining in 50 wpc triode mode, and I did play around with 100wpc ultralinear, but I seem to prefer the sound in triode more.

The reason I was inquiring is that second guessing myself is one of my many flaws.

@immatthewj No, I was more suggesting the idea that if the speaker were 91 dB instead of 86, that the amplifier would be doing far less work. You could get the same sound pressure you do now with 1/4th the power. So your 50 Watts would be much closer to 'unlimited power' and distortion would be lower; therefore more transparent.

Ah, now I've got you, @atmasphere  .  That makes sense.  And I suppose that is what I was thinking about when I posted this question.  

@atmasphere  , well, it does not seem to sound like (to me, anyway) as if it is straining, but by loafing, are you thinking that it would prefer being in 100 wpc ultralinear versus the 50 wpc triode mode?

I feel that my preamp (Cary SLP 05) has a lot of gain (and probably some of that is because I am using the balanced ins and outs) so I rarely move the volume knob  much past 9 oclock to achieve my desired listening level, but I realize that this does not necessarily mean that the amp is not working harder than maybe would be optimal.

Thanks, @ditusa  , I am going to have to print that because my eyes are so bad I cannot read that on the screen.