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

Depends on Co and sound quality.

@simna  With 12w and 95dp  speakers and only 190 sq. ft. room you can most probably  brake your windows in the house. 

But, I have never heard these systems deliver really low bass at a high level.

+1 @larryi

High efficiency speakers are the only choice to use with flea watt amps and that’s what they are usually paired with. Since bass requires a lot of air to be moved, a significant amount of energy is required, don’t expect extended linear bass.

The low watt amps are usually tube amps favored for their seductive midrange harmonic magic.

Most high efficiency speakers tend to be colored, but I did manage to find and purchase relatively linear neutral Volti Rival 100db speakers driven by the magical sound of my 300B 8watt amps. I wanted the cleanest window into my foray into flea watt amps.

I avoid low efficiency speakers as that limits amplifier choices to considerably more power and cost.

My non-flea watt speaker choice have mainstream efficiency which I define to easily run on 100-250wpc amplifiers. This affords me the greatest choices when looking for upgrade bargains. Like my flea watt speakers, i also wanted linear neutral clean window. I have the Vimberg Mino D.

@ tannoy56

That sounds nice. I will try to leave the window glass in the window frames :) 

The question: what is high sensitivity? Yes I agree. For real high sensitivity let say 98dB and up it is an issue.

My Classic Audio Loudspeakers are 98dB and flat to 20Hz. They employ dual 15" woofers as well as field coils to reduce distortion and compression while increasing speed.

I have a standing wave in the room that prevents bass impact at the listening chair. This issue was solved by the addition of a pair of Swarm subs asymmetrically placed in the room. I didn't run 4 subs because the main speakers go as low or lower than most subs. I used the Swarm subs because they are designed to be placed directly against the wall, inside the room boundary effect. This allows them to be more compact and out of the way; they are flat to 20Hz as well but not nearly as efficient, each using a single 10" driver. No troubles in the blend department though. No troubles with the WAF either :)