How important is the efficiency of a speaker to you?

Dependency and "seems to be" - as a technical observation I don't see how it holds an absolute correlation with regard the sonic outcome of SS amps in each and every case and high efficiency speaker combination, and to which degree?

@phusis Rising distortion with frequency can cause an amp to sound harsh and bright. A typical example would be if the distortion begins to rise at 1KHz which is quite common; the 7th harmonic is at the upper end of the Fletcher Munson curve, so due to the extra sensitivity of the ear at this frequency, the fact that the ear uses higher orders to sense sound pressure, and the emphasis added by the rise in distortion, you get brightness and harshness. As you know, harmonics are what the ear uses to distinguish the difference between a trumpet and a clarinet; if harmonics are added with emphasis in this manner it causes instruments to sound harsher and brighter. The degree to which this occurs has nothing to do with the speaker and everything to do with at what frequency the distortion begins to rise (the point where the loop gain exceeds the GBP).

Wouldn't the design of high efficiency drivers reflect more than a limited range of amp designs of their day?

For vintage speakers, no. For speakers made since the Voltage rules were adapted, yes. But you'll find, if you look, that most producers of higher efficiency speakers tend to use tube amps. At any rate the kind of amp used has nothing to do with the phenomena of thermal compression. My speakers were designed for amps of higher output impedance, but owing to level controls for the mids and highs (which are there even on vintage designs to allow the speaker to be adjusted to the Voltage response of the amplifier) they work fine with my class D amps.

Interesting, and informative article. Offering technical insight it must also come to acknowledge that what is advocated here can as well be counteracted perceptively, if nothing else by the myriad intricacies of a context:

What are you trying say here? If we didn't have ears, its unlikely that we would be playing around with audio equipment :)

Amazing how complex and convoluted this discussion is.  I don't think there's a good answer here.

Except, having a Quality tube or solid state amplifier with plenty of power is undisputably a good thing. Yes there are speakers that can run off of 10 W of tube power.  Although this confuses the hell out of me.

Sensitivity of speakers is really confusing to me except that more sensitive speakers can be played with low power tube amplifiers and there may be some value in pursuing this because there are plenty of really good tube amplifiers running off of low wattage this can be a good thing. And we all know tube amplifiers are better than solid-state.

It's also good to buy a dog rather than a cat because the cat could care less about you.

It is extremely important to acquire a speaker that has a good synergy with the amp that powers it.

Tube gear is likely to be noisier than ss gear

@daveyf agreed. However, one can get the speaker first then get the matching amp subsequently - this has been my current strategy.

I have 2 speaker types.

Efficiency doesn’t matter - I purchased a full range herculean braced full range medium sensitivity speaker from a AXPONA demo that "resonated" with me. For this audio chain, I’m interested in transparency and dropping the noise floor.  I use highly regarded SS electronics

Efficiency matters - I wanted a "neutral", affordable, reasonable sized, speaker that can handle flea watt amps and other low powered tube amps. Purchased a 100db speaker specifically to explore tube amps including flea watt. I didn’t think much about synergy as I plan to experiment hearing different tube amps starting with the 300B, and the manufacturer confirmed I can also try a 45 tube amp.

Good luck with your speaker search

@kennyc The only thing that I think also needs to be added, or considered, when one goes and just buys a speaker that is requiring a monster amp upstream, is this…. That particular amp will most likely ( I can think of maybe one tube amp that might work, and it too is very expensive) be a very expensive ss high powered amp.The problem is that many of these very inefficient speaker designs, which can sound excellent, are also typically very pricey by themselves. So, not only is one now digging deep to just buy the speaker, but also one has to consider the potential for in many cases doubling the cost to acquire the amp,unless of course we are talking about Parasound’s…@rauliruegas

@atmasphere 

Im going to depart with your thinking when you say things like

"There are attempts to get around the thermal compression problem with lower efficiency speakers, such as vented pole pieces and the like. The incentive is high because lower efficiency speakers are a lot cheaper to make."

This is simply not true.  As mentioned before and elsewhere, lower efficiency drivers may sacrifice some efficiency to gain other features that improve performance such as lower distortion, better linearity, better low frequency extension etc.   The idea that lower efficiency is always done as a cost saving excercise is clearly not true.   

Brad