Recommendations for speakers that sound great at lower volume levels.

I have a pair of Harbeth SHL5 Plus and they sound wonderful when I crank them up. But at moderate to low volume levels they sound disappointingly flat and unengaging - instruments are less palpable, bass has less bloom, and soundstage has less air and dimensionality. I drive my speakers with a tube integrated - a Line Magnetic 845 rated at 26 watts of power. My Harbeths are rated at 86db. Would a higher sensitivity speaker be helpful? Or how about a good quality small shoebox sized pair of speakers coupled with a subwoofer? Or not. What speakers are going to deliver music you can feel at low volume levels? What say all you wisened audiophiles?
The monitor audio platinum 100 is a very nice speaker. The persona b is very bright one of the reviewers actually hated it.
A truly great speaker in which I am saving for and heard many times. 97db efficient ,8 ohms very minimal Xover 3 parts , the Spatial Audio Labs Open Baffle X3, X5   Great Custom Beyma AMT tweeter-Midrange driver in a wave guide,from 1k to -30 khz , 12 inch midbass
From under 1k to 90 Hz then Hypex power Bass to 25 HZ 
x5 12 inch woofer, X3 -15 inch woofer 
$6995 is a steal it beats speakers 2-3x the monies. In my tri state audio club I have heard dozens of quality speakers . I didnot think 
open baffle would be good , I was very wrong ,no box colorations 
fast open and great detail , imaging microdynamics at a whisper 
to thunderous loud and even a small amp of 15-20 watts ,at 97 db 
efficient ,verygood .one highly rated upgrade , VH Audio Odam capacitors I believe 2 per speaker  msybe a $5-600 upgrade 
and worth everypenny . They even have I believe a 60 day return policy .Clayton is great to work with .I owned his original 4 open baffle these are night and day better.
Caintuck Open Baffle Lii 15 in coax. They are delicious and under a grand. Randy is the best!
As mentioned before, high efficiency speakers tend to keep a better tonal balance at lower volume levels (around 45~50  dBA  SPL). In my case, a friend who was visiting mentioned that the Tonian 12.1s I had installed in my living room sounded good at a very low levels. They are about 97db/W/m.
As mentioned before, high efficiency speakers tend to keep a better tonal balance at lower volume levels (around 45~50  dBA  SPL). 

Must be different for planar speakers, my apogee duetta 2's sound great at low SPL's.