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.