How important is the efficiency of a speaker to you?

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....

I think many of the values discussed here and elsewhere assigned to high efficiency speakers are not accurate. First the entire discussion of what is delivering the improved efficiency is not differentiated- is it drivers or how the driver is used that gets you better efficiency? These two ideas.make a huge difference in performance but are distinctly different methods of achieving improved efficiency with their own costs, benefits and penalties..

Example 1: a lower efficient driver can be made more efficient by placing it on a horn, which complete changes other characteristics/parameters of performance and behavior. An acoustic suspension system or a horn system are very different from each other in many ways having a direct impact on performance.

Example 2: You can build a more efficient driver by lowering the mass of its moving parts. Lowering this mass can cause multiple things to happen, typically increasing ring modes and distortion. Here efficency makes the driver sound worse. Another outcome of lowered mass is poorer low frequency performance.

Example 3 Higher efficiency drivers do not always offer lower power compression. If you use titanium instead of aluminum for your former, the thermal resistance is far higher with titanum than aluminum, so heat can’t escape the lower mass system increasing thermal power compression. Higher efficiency increases thermal power compression in this case. DO you know what your VC former material in the speaker system you buy actually is? Thermal power compression is affected by a long list of factors that are far too detailed and complex to discuss here or ina spec sheet: issues such as VC impendance, VC material, front plate/pole piece proximity to coil, airflow and venting of the magnet system. Looking at a efficiency measurement and assessing quality is like looking at frequency response and assessing sound quality- it really isn’t an indicator of performance in a way that is simple or easy to [universally] understand.

I know poeple really want there to be a simple way of looking at things but this is some deep science. A speaker involves practicaly all the sciences and there is no way to simplfiy it and express that in a spec- unless you are willing to bullshit or tell a helluva convincing marketing story. Most do exactly that, but its a diservice to the thinking person’s aims in a playback system.

If you love the idea of a flea watt amp, you are sorta stuck with high efficiency loudspeakers to have any hope of dynamic range. If you are more open minded and are wiling to look at moderate efficiency speakers in the mid 80s, using the wide array of excellent high power amplifiers available, or active speaker configurations, you can have your low distortion, wide dynamic range AND better bass AND wider dispersion, etc, etc. But you cannot have all that AND super high efficiency.

I think we are back to listening to a speaker with a proposed amplifer and assessing if this combination works for you and addresses the things you care about.

Brad

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You can also make a more efficient speaker by "tightening up the tolerances" (i.e., tighter fitting voice coil/gap) and increasing the number of windings within the same area (e.g., using flat-wound wire), without causing other problems.

BTW, a lighter cone will also allow the driver to play to a higher frequency without break-up.

My "Merman" speakers are extremely efficient, and sensitive, without horns, and can easily do "live concert levels" and I wouldn’t have it any other way.

Remember that the volume control is nothing more than a "focus knob" and sometimes you really need that volume to bring the cut into focus.

Also, I feel that an "immersive experience" takes realistic volumes to achieve.  You can't immerse yourself in a tub of water if it only covers your toes.