How important is the efficiency of a speaker to you?

This sounds like Wilson Audio, which I have.  Do not assume everything you read.  I recently auditioned a pair of Alexia 1 that are supposed to require lots of SS power.  The sounded better and more musical at the same output with an Audio Research 75SE than they did with a McIntosh 450wpc SS amp.  

The speakers I was referring to were not Wilson's. Nonetheless, it is interesting what you posted about Alexia 1's. They are known to be extremely difficult to drive. Is it possible that the ARC Ref 75SE has a more capable transformer, and as such can drive the Alexia's? 

Interesting discussions on efficient speakers...  I have run through the gambit of lower efficiency 87db-89db speakers and efficient 94db and very efficient 103db - 106db.  And I've also gone through the same regarding the amps I believed needed to drive them.  After my experiences over the past 20+ years, I moved toward the higher efficiency types (94db - 106db) with low-wattage (flea-watt) class-A single-ended both tube and solid-state amplifiers.  As I moved from lower efficient to higher efficient speakers keeping my higher-powered amps in play, I could tell the difference in micro-detail.  Going then from the higher-powered amps to the flea-watt amps, there was a slight but noticeable improvement in micro-detail, with no loss of dynamics or bass response at my normal listening levels.  Those speakers by the way had impedances between 6-ohms and 8-ohms nominal and all had multiple drives/crossovers.  Presently, I'm using a single-driver speaker with of course no crossover, that is 106db efficient with a 12.9-ohm (resistive) impedance.  Every one of my flea-watt amplifiers can drive these speakers to uncomfortable listening levels with absolutely no loss of any dynamics.  However, I would expect that at a 106-db efficiency, and at the rather high 12.9-ohm resistance.  Even my 94-db speakers were driven with the same flea-watt amps with no dynamic compression at comfortable listening levels.  I have not heard a variety of lower efficiency/impedance speakers, however in every case with the speakers I've had, the more efficient the speaker, the greater micro-detail I've heard.  The only other lower efficiency speakers I've heard equivalent or better micro-dynamics, especially in the upper mid/tweeter frequencies are planar speakers.  Perhaps that has more to do with the lower moving-mass of the planar electrostatics than the efficiency.  Finally, one of the tests for me was the low, no-signal noise from the electronics through the speakers.  If you can hear that slight noise with very efficient speakers versus lower efficient speakers, what micro-detail would you then be missing in the music with those lower-efficient speakers ?  Your individual experiences may vary.  This is just what I've seen/heard over the years...  

@dhite71

+1

There has been this old adage of tube watts being more powerful than solid state watts. For most of the last fifty years I used mammoth high powered solid state amps. Then about five years ago switched to Audio Research Reference amps 160m monoblocks and 160s. I run the 160s in triode mode… so only 70wpc and they are ferociously relaxed and powerful, absolutely no lack of muscle… but they don’t flaunt it… it is just there, rock solid at any volume.

I also have a friend with a pair of Wilson Puppies and an Audio Research VT80. They drive the Wilson’s to incredible loudness without any sign of running out of power or dynamics, rock solid. I really cranked them last weekend.

While I haven’t recently tried to put 70wpc tube power up against solid state but I am pretty sure it will stand up against two or more times the SS watts. So, I had figured the old adage of the difference between tune and SS was really subtle. It isn’t and still seems to be there..

Ok I have Polk lsim707 ,88 db and thery are driven with a Caryin XL 55 tube amp light 20 wpc and they sound great....there in a very large room with cathedral ceilings....i was,told owe you can't drive them with that tube amp....you need 300 wpc.....well they were wrong ,totally. I have used these hook up for 2 years.....no problems at all....