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

Hello TANNOY56!  If you have Tannoys, you're used to high efficiency speakers. Three cheers for you! You can use those gloriously liquid low watt tube amps and annoy the neighbors. Imagine a 104 db sensivity speaker vs a 94 db spl and a 84 db spl speaker. Have you ever watched the dancing meters on some bit of audio gear? Have you noticed that a 10 db difference doesn't sound like a big deal? To play as loud as the 104 db speaker, the 94 db speaker needs 10 (ten!) times the power; the 84 db speaker (the Maggie LRS comes to mind - I love them) needs 100 (yes, one hundred!) times the power for the same loudness.  If you music is cruising along at four watts, the 94 db speaker will need 40 watts, and the 84 db speaker will need 400 watts (!) for the same lloudness. Efficiency is a wonderful thing. Think aboout amplifier headroom. My maggies are driven by a 400 wpc amp. They sit atop a pair of high efficiency speakers driven by a 9 wpc 300B tube amp.

There is very little difference in the sound. Why use more electricity than necessary? Why heat up the parts in the amp and shorten their life? Get the picture? I very much admire Nelson Pass. I have two of his amps. They sound great. And they heat up my TV dinners. Ouch! Environmentally . . . ?  Happy Listening!

 If you music is cruising along at four watts, the 94 db speaker will need 40 watts, and the 84 db speaker will need 40 watts 

For many listeners typical/average listening volumes fall in the 70-80 db (C-weighted) range. A 104 db sensitivity speaker is probably using 1/100 of a watt. The 94 db speaker roughly 1/10 watt. Either way, minuscule power draw from amplifier at very reasonable listening SPL.

Charles

The beliefs around speaker efficiency is sometimes silly. All those numbers mean is how loud a speaker is when driven with 1 watt of power. A 3 watt "flea" power amp putting out 2 watts with any speaker, will produce the same level as a 400 wpc monoblock delivering 2 watts into the same speaker. 

Then again, some people have the erroneous belief that more power sounds better. If that was the case, the very low powered amps would sound terrible. 

My take on this is, that if you are not stuck with worrying about keeping efficiency then you can use components and crossovers that may provide a flatter frequency response without compromise. Often you have to compromise the response to keep the high efficiency. Having said that I think there are good loudspeakers in both camps.  

y’all understand distortion counts as output..in the overly simplistic efficiency measurement…. right ?