What is your take on high efficient speakers vs. low efficient speakers?

I sort of think that 95-96 is at the low end of the range.  My speakers are 99 db/w efficient, and friend calls that medium efficiency (his speakers are above 112 db/w efficient.  It also matters how smooth and high is the impedance curve of the speaker.  I recall how one of the Wilson Watt/Puppy speakers was supposedly 95 db efficient (at a nominal 4 ohms, meaning some more realistically at 93 db/w efficient) which should have made it fairly easy to drive, but it turned out to be a very demanding and difficult speaker to couple with some tube amps.  On the other hand, the original BBC monitor LS3/5A (15 ohm version) which is rated in the low 80's as far as efficiency goes, couples well with even somewhat low-powered amps because it is a very easy load.  

@larryi wrote: "I sort of think that 95-96 is at the low end of the range. My speakers are 99 db/w efficient, and friend calls that medium efficiency (his speakers are above 112 db/w efficient."

Imo this is something to be aware of:

Very often the limiting factor for high-efficiency systems is the on-axis frequency response at high frequencies. And one way to get very high efficiency numbers is to use a horn whose pattern at high frequencies is very narrow, such that all of the high frequency energy is concentrated in a narrow beam, thereby maximizing the on-axis sound pressure. If the same compression driver were used on a wide-pattern horn, the same amount of acoustic energy would come out, but because it’s spread over a wider angle the on-axis PRESSURE would be less.

By way of analogy, consider a garden hose with an adjustable nozzle. The on-axis PRESSURE is higher when the nozzle is adjusted for the narrowest possible pattern, but the same AMOUNT of water comes out regardless of the pattern width. So too with horn radiation patterns.

Implied by this is the fact that an omnidirectional speaker system is actually putting out a lot more acoustic energy than we would normally infer from its "on-axis" efficiency.  So comparing efficiency (or voltage sensitivity) specs is not necessarily making an "apples to apples" comparison.

Duke

+1 @stereo5 

High and low efficiency values can be somewhat objective. Seems like the majority (in past conversations) consider high efficiency to be greater than 95db, and many consider low efficiency to be 89db or less. Where does that leave the 90-94db speaker?

@stereo5,

See chart below:

Mike

@blisshifi agreed…

Except aren’t we talking sensitivity?

so 90-94db= “medium sensitivity “ lolololol