Speaker sensitivity vs SQ

So the story usually goes like this.

Back when tube-based amplification was the only option, and most tube amps were really low powered, designing speakers with high sensitivity was the only way to go--there was simply no alternative if you wanted to reproduce voice or music.

With the advent of transistors, and then ever "cheaper" watts, designers started creating lower sensitivity speakers.  Think Thiel, Apogee, and a bunch of others.  It's reasonable to assume that they had specific design goals that led them in this direction, and that it wasn't the result of a lack of effort on their part.

The renaissance of tube amplification has seen a similar movement among suitable speakers, so nowadays there are plenty of options for everybody.  Of course, it's preposterous to rule out all speakers under a certain sensitivity.

Another major factor here is impedance; speaker sensitivity doesn't exist in some kind of electro-acoustic vacuum.  A certain well-known brand makes speakers with 86dB sensitivity but about an average 12 ohm impedance.  Go figure.

The long and the short is: find the speaker first that most pleases you, then find the right amp to drive it.  This advice has already been repeated many times over on this forum.

So there must be other factors. Why don't all speaker manufacturers build exclusively high sensitivity speakers?

@clearthinker  Cost, in a nutshell. High efficiency drivers are much more expensive due to a greater degree of precision required to precisely place the voice coil in a narrower gap, plus a more powerful magnet system.

b_limo1, great video, have seen it once before. Interesting perspective.

tomic601, When you say "don't confuse low sensitivity with poorly engineered load". I feel they are closely related. And I believe this is John DeVore's point in the video. I know of a high end speaker that is rated at 90db at nominal 8 Ohms (2.83v at 1 meter), have listened to it many times at a friends place. But when you look at the measurements of that speaker it has dips in the impedance down below 3 Ohms as low as 2.6. The speaker maker is only telling us a partial truth with their specs. It is only a 90db speaker for some of the frequencies and in effect a much harder to drive speaker to pull out all the audible sound well. Which I believe plays into the issue pointed out on the video of 1W per meter vs 2.83v per meter can be deceiving. With this particular speaker, you need an amp that doubles down on power when you halve the impedance to sound right. In other words it needs an amp designed for low efficiency speakers.  

I own Mission Cyrus 781 speakers sensitivity rated 90.5 db...

I drive them with my Sansui AU 7700 rated 8 ohm 55 watts....

No problem....I can make deaf my neighbours.... They sound  very refine and bass powerful...



😊

+1 newres, well said. 

Speaker manufacturers ask for 10s of thousands of dollars,  play fast and loose with sensitivity numbers, and (usually) don’t publish any impedance graphs. Mostly we’re left to hoping that JA has tested the speaker and published results 

Hate car analogies, but here goes.
How much? $80k
Horse power? Don’t know
Torque? Hmmm, good question 
weight? Not sure...