What is the benefit of low efficiency speakers?


I know 8 ohm speakers are easier to drive than 4 ohm speakers, and most decent amps can drive nearly anything, but why are some speakers made with loads that drop down to two or one ohms?

Are they designed to cause, or allow some certain aspect of the sound to come through that would not otherwise be heard? What's the point of making a very difficult to drive speaker? Did that sentence make sense?
uppermidfi
First of all, the resistance (ohms) of a speaker have nothing to do with sensativity.

Sensativity is usually stated in how much volume (in db's) is produced with one watt of input.

I think you should buy Robert Harley's book on high end audio. It may answer many of your questions.

Richard
Yes I agree, I can also think of none. That is unless you like Set low watt tube amps. My friend has a 300B Set amp with $6K high sensitive speakers, the Sonatas I believe, rated at 93 db, they are great on some things, jazz, vocals, but they do "bark" on male vocals at a certain fq, it is a 3 way, has a midrange, which I never in 30 yrs listening like the sound of a midrange driver. NEVER.
I have the Seas Thor's a MTM, W18+T25+W18, rated 4ohms, 86db!!, but very very nice in all areas. Take a look at Tyler's MTM, same as mine, I have the kit Thor from Madisound. I'm driving them with the little Jadis Orch Refer, has 4 KT90's. I use it with the tone controls up 98% for the extra dynamics in the bass and especially the highs.
So yes, a 87db speaker does reqire some good wattage to bring forth the dynamics. But to answer your question, NO it does not matter whatsoever, low sensitivity, high sensitivity. What matters MOST is how does the drivers voice the music. Get it. How does the music come forth from the speaker. Natural? No bark in vocals? Soundstage? Does it sound lifelike? Does the sound have fatigue? (all the above is the same question posed in various ways)
My Thors have zero fatigue. The Danish have been working on the Seas drivers for 50 years. I guess they got it right with the Excel line.