Sometimes Hard to Drive Speakers are a Gimmick

@atmasphere 

Many amps can drive difficult loads but that isn’t the same as saying they are sounding their best while doing so. For one thing, distortion is higher. It may not seem like much, but since our ears are tuned to using higher ordered harmonics to sense sound pressure the slight increase in distortion is heard as a less relaxed, less authoritative and less detailed presentation. 

Put another way, if you want the most out of your amplifier dollar investment, it will be best served by using a speaker that is easy to drive and more efficient. Amps sound best when they loaf for a living rather than working hard. 

I don’t think speaker designers make speakers harder to drive on purpose so much as they just don’t know any better because they don’t also design amps. 

I agree with everything Ralph (atmasphere) said here.  The one thing to keep in mind is the first word of my post: "Sometimes."  

I agree some speakers are just.. unfortunately poor crossover choices.  Some speakers, by nature of the  physics of their construction are never going to be an easy load.  I’m also not going to whine about speakers that squeeze in a 3rd woofer in a small cabinet to get a little more bass out of a small footprint speaker.  Balancing out sensitivity and size requires tough engineering decisions and not what I'm trying to point out here. 

My article, and frustration, is about a third and very rare situation, of which in my years of looking at speakers I’ve found only 3 possible candidates. 

Evidence of what? 

Name these 3 candidates. 

Hi Erik, I think a most famous amp burner was the Infinity Kappa 9 with essentially a reactor in the woofer circuit. Huge capacitance in series and big shunt coil.

In crossover experiments, I can't escape the fact that complex crossovers have an audible penalty of truncating the decay and making each driver only carry an unnatural sounding limited range. So your ear has to stitch together the sound.

Another strange thing I had found was that wiring identical drivers in series makes the imaging drift and it was better to parallel and add resistance. Apparently the inductance of the voice coils creates perhaps a phase shift favoring one driver over the other in complex waveform.

I have never heard a 4th order I liked, the less you can get away with the better. Also each shunt element is consuming amplifier power and making back EMF to some extent. Speaker building can be the most frustrating yet most rewarding thing when it finally dials in..

@audition__audio - Seems like you actually skipped my post and the blog where the data is kept.  Maybe start there. 

Efficient impedances are generally a good thing, but it does not replace the higher goal of personal sonic preferences.  

Inefficient impedances does not “logically” lead to a conspiracy of speaker manufacturers with amplification manufacturers.  There is no proof.  There is no motive.  Rather, manufacturers simply make products to work with other products readily available in the marketplace and that includes flea watt to high powered amplifiers.  Their efficiency only needs to reach “good enough” vs “optimal” which may cost more time, expertise, and resources.  

Speaker manufacturers do not determine amplifiers wattage, it’s the market that determines what is in demand - speaker manufacturer does not have a monopoly to control anything.

The OP is looking inward to draw conclusions of the outside world rather than seeing how the outside world functions.  
I’ve been to the Magico manufacturing headquarters- they use cutting edge equipment, technology, engineering, and materials to design speakers to minimize errors.  Efficiency is only one element in their design decisions.  Some low watt amplifiers may not be able to fully drive their speakers, but that’s not their target market- there are plenty of capable amplifiers available.