Speaker sensitivity vs SQ

Hmm, I recently bought a new set of floor standers that are rated only 2 to 3dB lower efficiency than my existing floor standers.  This is in a 5.0 surround setup and the floor standers are used for the front L/R channels.  I have a very powerful amp powering the front L/R speakers, which should be able to deliver plenty of power to either of these sets.  Now, when watching movies with the new set, it just seems like the sound from the front L/R speakers is a bit anemic compared to the other set. 

I did use a sound meter to raise the sound levels in the new set to match my center channel speaker sound level.  Thus, both the old speakers and the new ones were set up to match the center speaker level. 

@mijostyn wrote:

"Duke, your friend has more work to do. There are so many factors involved that I doubt you can make a blanket statement that high efficiency speakers are ALL more dynamic than low efficiency speakers of various types given appropriate power. "

I don’t think I made a blanket statement. Here is what I actually wrote:

"My friend finds a STRONG CORRELATION between efficiency and freedom from compression on peaks... IN GENERAL high efficiency and large-diameter voice coils translate to freedom from compression on peaks."

Emphasis mine in both quotes.

In my opinion "strong correlation" and "in general" are not blanket assertions, whereas "all" would have been. 

Duke

Everything that I’ve ever read about dynamic speakers agrees with Duke’s friend's observations.

Bigger voice coil, more ventilation, lower power dissipation result in lower dynamic compression. Of course, all things are not ever equal, but the difference in engineering speakers for professional, continuous high power use vs. consumer speakers is all out there to read. If you want to maintain high output you must control the heat, weather by reducing power dissipated or increasing ventilation or both.


@audiokinesis

First, thanks to @b_limo for posting the DeVore video. I hadn’t seen that before and it is the best explanation of the relationship between sensitivity and impedance I’ve ever seen.

Several good answers to the original OP question but I wanted to add my own experience. For some reason I’ve been attracted to the sound of low sensitivity speakers for as long as I’ve had this hobby. It goes back to a pair of Large Advents that I bought in the 70’s after I heard a friends AR speakers. In a trend that has lasted my whole audiophile life, I invested in amplifiers that would drive difficult speakers. After I got my Advents I bought the biggest Marantz receiver they made (2325). Then I upgraded to an Adcom GFA 555.

When I upgraded the Advents in the early 90’s I listened to over a dozen models and I definitely preferred the less sensitive candidates. I settled on a pair of Mirage M3si which have an 87 db sensitivity. Then I upgraded my amp to a Krell KSA 300S. A few years ago I snapped up a pair of Thiel CS6 that a friend had for sale. These speakers driven by my monster Krell make some of the best sound I have ever heard anywhere.

When I went to AXPONA and the Tampa Show in 2018 I realized that I seemed to prefer speakers with lower sensitivity over those that were very sensitive. I didn’t hear a setup using a single ended tube amp that I lusted after. And I concluded that horn speakers aren’t my thing. They do some things very well but overall they just didn’t light my fire. But I can completely understand why some people love them.

My point here is that the sound resulting from the tradeoffs that low sensitivity speakers incorporate appeals to me for some reason. For the last 40 years I have been willing to invest in the amplification to drive these speakers and I’ve never regretted my decisions. Bottom line, high sensitivity or low sensitivity is not better or worse, it’s one of the many design decisions that speaker engineers make. Once they go a certain direction they optimize their design for the sound they want and sometimes that leads to low sensitivity and low impedance. I happen to be one of those audiophiles who is willing to suffer the cost and back problems of having an amp that will drive these things.

@erik_squires , thank you very much for that information on Siegfried Linkwitz's tone burst tests!    

I was aware of the article in Stereophile years ago which "debunked" short-term thermal compression, but the methodology in the test was flawed because it looked at the average compression over time, rather than the rapid-onset compression that Linkwitz's test reveals.    

"Bigger voice coil, more ventilation, lower power dissipation result in lower dynamic compression."    

That's my understanding as well, but JBL went a step further in their M2 studio monitor:  They use an alloy in the woofer's voice coil whose resistance stays essentially constant as it heats up.  I'm not sure whether they did this for the compression drivers' dual voice coils as well.  Anyway that seems to me like a brilliant idea which would be especially welcome in high-end audio speakers where efficiencies are lower and therefore voice coils are smaller.  

For the record, my own priorities are much more focused on speaker/room interaction, and the types of drivers which do what I want in that area just happen to be fairly high efficiency.  

Duke