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?
harbeths are actually considered to be very good at low levels and nearfield

if you like the harbeth sonic palette maybe try a smaller model... c7, mon 30, p3?

of course the famous bbc ls3/5a was the original brilliant nearfield mini monitor, with bumped up midbass to fool the ear at lower volumes into thinking it is more full range than it is... of course the treble and midband are beyond reproach

excellent related or descendant speakers of small form factor for lower level or nearfield listening from atc, proac, spendor, kef, sonus faber, and so on - there are many many out there, with different sonic presentations

+ jjss49
Any Ls3/5A design would fit the bill. I’ve owned quite a few and the Harbeth P3 is still my favorite of the lot. I have also owned larger Harbeths and IMO the P3 is the pick of the litter. And I don’t use a subwoofer!
Yogiboy - I've wondered about the P3 compared to SHL5. Can you offer more detail about the p3 and why it's your pick among Harbeths? Thanks.
I have owned the Harbeth M30.1,C7 and the newer P3ESR. In my 20x15 size listening room using tube amplification the original P3 just sounded better. I always prefer a sealed speaker better than any speaker with ports. BTW, I have tried many different speakers and I always go back to the P3. I have owned five pairs so I learned my lesson not to change to other speakers just because they are pricier and bigger!
This guy likes them like I do!
I’ll give another endorsement for British mini monitors. I have small to smallish listening rooms. I also listen more times than not,at low volume. My Graham Chartwell LS3/5’s do a wonderful job at low volume. They soundstage freakishly well. I also run them with a couple low power First Watt amps. They will always be in the rotation for me. The great thing with these mini monitors,is you can flip them if you don’t like them,and probably break even at worst. 
+1 on the LS3/5a... had an 11ohm set of Rogers from the mid 80s and just loved them. Wish I still had them... playing a set of Equation "7" these days that are just incredible in my kit. Listen late night in a dead quiet room and paired with a Cary tube amp and Manley Shrimp tube pre they are incredible. Won't find much on the web and the distributor in Canada, Mutine, got beat up pretty good on here a while back but they are special. All hand made in Belgium with the finest components and internal wiring. Had no idea what to expect other then they mated well with
low powered tube gear. The "7" were the bottom end of their line and retailed for $3K in '05. Said to be perfect symetry between Equation speakers and Audiomat electronics; the Arpege integrated specifically. Have heard the Audiomat gears and sadly never got the chance to pair them togther. Anyway, fabulous at low volume - everything's there full and robust. A real treat if you can come across a set. Maybe $13-$1500 depending on condition; worth every penny. 
I owned the Harbeth SHL5 Plus and earlier versions of the SHL5 and they all sounded great at low volumes. I actually bought them for that reason. The issue is more likely to be your amplifier. Harbeth's, when used with SS amps like Ayre, Aesthetix, Naim, Musical Fidelity and many others excel at low volume. 

I've have never heard a Harbeth speaker that sounds good with any tube amplifier though many others will disagree. If you like your amp you should work with a Line Magnetic dealer to find the right speaker for your requirements. You might also find a dealer who would loan you a SS amplifier to try in your system to see if the Harbeth's might actually meet your low volume needs.

Good Luck!
I have Salk Exotica Raal monitors.  I can highly recommend them for low level listening.  I marvel at the sound every day.  I listen a good portion of the day while working.  
This afternoon I was listening to my Quad ESLs at very low volume: pure magic. BUT not bass you can feel - I think that's impossible at low volume.
you need a big subwoofer (it will add bulk, but not volume) + a good preamp ...
The best late night low volume listening I have had was with Magnepan MG-20..............but it was also a heck of a system...CJ ART, etc.  I have had Martin Logan, Advent, Vandersteen and others.  The myth about efficiency and low level listening is just that. 

Quite true @terry9. That's a result of the Fletcher-Munson characteristics of human hearing, not the Quad ESL itself. Of course, a speaker with more bass output at higher levels will have that at lower levels too, relative the Quad.

Got a pair of Cornwalls specifically for this reason. 
Also have a pair of ESL-57’s which also, as it has been stated above, sound lovely at low volume.

Big speakers that are high efficiency do help in low volume listening.

Low noise, low distortion, electrical synergy, a quiet room.  The whole signal path is relevant for engaging low level music.  Don’t just blame your speakers.
What you need cannot be achieved by ANY speaker (except a subwoofer).
What you need is an amplifier with the good old fashioned loudness control.

some thoughts- if you just came from a high-noise environment such as work or the noisy highway commute, your ears will take a good while to re-adjust their fletcher-munson loudness thresholds. just like how your eyes [when exposed to bright light] take a good while to adjust to low light, so too your hearing must similarly adapt to quiet after loud noise. so wait at least a half-hour before you listen to music after work. also if your room is too crowded/densely furnished/carpeted/upholstered, that will interfere with low level detail retrieval in my experience. you need room for your speakers to bloom. you also need to live in a quiet house in a quiet neighborhood, your kitchen needs to have a door on it [fridges and freezers generate a LOT of brown noise], you need to turn off your central heating/cooling while you are listening because they generate lots of brown noise as well. do these things and suddenly you will find that your speakers now sound as though the blankets have been removed from them. you will be amazed at the sonic fullness and details you hear. 
Cakyol, thanks!
Can't believe no one else mentioned that.
The human ear simply does not hear higher and lower frequencies as well as the mid range at lower volumes.
A speaker would have to be far from flat to sound great at low volumes and would sound awful at higher volumes because of abnormally loud lower and higher frequencies. 
Loudness controls addressed that limitation.
My Parasound has bass, treble and sub level controls on the remote, so I can adjust the levels accordingly when listening at low volumes. It also has a "flat" button....that returns bass & Treble to the proper, flat levels with a single push, when it's time to turn the volume back up. I know, many goners are rolling their eyes at such a feature, but it serves my purposes well.
I have 30.2's and drive it with a Luxman 590AXII that has a bi-passable loudness control. They sound wonderful at low volumes. Yes, I know, tone controls are looked down upon. However, as Ccakyol  stated and mwinkc chimed in, a loudness control is what is needed at low volumes. It's one reason I went with the Luxman, aside from the Class A power, as I wanted something close to tubes without the heat and tube issues. I don't think changing speakers is the answer. I am sure you'd hate to part with the Line Magnetics, but I'd say it's not a good match for Harbeth speakers. I am lucky enough to have a Stereo store close by with both the Harbeth and Line, and I did not like the combo. YMMV.
Doesn’t exist!    Have a read up on Fletcher Munson Curve.

Some will tell you XYZ speaker does it.  In my experience those guys seem to enjoy music with zero bass or dynamics.  I can’t.

My only advice for those late night listening sessions is either get yourself as near to the speakers as possible for intimate listening.
Or get yourself some decent headphones.

Biamp these speakers. Perhaps a ss amp for the woofers. They will come alive at low levels. 
As someone Else wrote. You need a amplifier that can deliver enough curent when needed and minimum 50 Watt.
I drove mine with Maek Levinson 383 integrated and they sounded superb. 

I upgrade to Quad ELS 2813 and that combo is not something i have regeret yet😉

Loudness controls are an interesting topic.
They have been universally denigrated by audiophiles.

But it is true human hearing has less acuity at frequency extremes - demonstrated by the fact most of us can hear nothing at all above 25kHz or below 12kHz.

But that is how all of us hear everything from birth to death.  So do we benefit from changing that pattern for listening to music?  An obvious response is that the hard of hearing benefit from hearing aids.  However this is not a reasonable comparison with those of us with normal hearing.

A mid-point perhaps is those who are older and suffer from natural detrioration of HF range and intensity.  There may be benefit in increasing the intensity of the HF signal.  This was achieved by the treble control, which with its LF parner has been out of fashion many years now.
Some loudness function do emphasize the high frequencies as well.  The Fletcher Munson curve did include a boost in the highs as well.  Yea, it is a shame that this has all but eliminated.  Our shop deals mainly in vintage gear.  Almost all of it still has this feature.  The most useful were the variable loudness versions used by McIntosh and Yamaha.  
Hard question to answer without knowing what kind of music you listen to and what your expectations are.  I've owned the SHL5s, but now I'm using P3s in the same room and I think they do better for low volume playing.  But, IMO, if your amp sounds good with your speakers at higher volumes, I'm not sure a more powerful amp is the answer for lower volumes.  A loudness control would be best, but alas. 
Interesting. I had no idea how much I would come to value the Loudness button on my new Luxman. One of my musician buddies called it a "guilty pleasure" the other day and I couldn’t help but laugh. I keep it on up through about 75db listening threshold, curious if that is "low volume" to many of you.....

@clearthinker I would say "had been denigrated by audiophiles" as to me it seems they are back in vogue just a bit. Look at PS audio YouTube vid on this concept.

Agree on the overall statement that Loudness + sensitive speaker is likely your best outcome.
Every single loudspeaker you will ever own will do the same thing. Actually, it is not the loudspeaker. It is your ears. Better yet , it is everyone's ears. Google Fletchur-Munson curves.
What you need is loudness compensation. Older preamps usually offered a single level loudness filter but in the "No Tone Controls" era the filter was dropped. Consequently, if you want a recording to sound right you have to play it back at the volume it was mixed at which depends entirely on the mastering engineer. Loudness compensation will give you a lower volume that the recording will sound "right" at. In the digital era this is easy to do without adding distortion and ruining the image. Those with room control can program their own loudness curve into one of their presets for times when they do not feel like shaking the shingles.
A great low volume speaker is a pair of stand mount Fritz Carerra BE Speakers.  I recently picked up a pair and they are fantastic.
I listen to some Altec Lansing A-7 500's that are 16 ohm, driven by Decware, 6 watts/channel.  Very sensitive speakers that sound unbelievably great at all volume levels.  I have found some things that have the sensitivity is 95 and as high as 115 db.  Whatever it is, wow, they sound great.  I have tried Caintuck's open baffle and found them very pleasing at low volumes and Blumenstein's.   That said, I had some Maggie's in 3.5R's that were similar to your Harbeth's, it was like they were asleep and not nearly as dynamic until you cranked some heat to them.  Then everything woke up and it was incredible.  I believe that both Nelson Pass and Steve Deckert would say about their products, "good from the first watt".  Might try to find something more sensitive for speakers.  I had a long discussion with Steve Deckert when buying the amp and as he said, "nothing beats a single ended triode for sound, unless you are drinking some beers and want to really crank it".  Another option, as those are very nice speakers, I have had some good luck with a high current amp (not watts), driving some Linn LS35A's.  Another option is to reach out to Harbeth and explain your issue, see what they recommend.  I am a collector and not a seller.  If you do something, I would keep what you have and add to it.  It is so much fun to play new combinations of speakers with different power and input.  Good luck. 
I have also noticed great low level, balanced sound with my Salk Songtowers. It's as if I have a subtle loudness switch on all the time. This is regardless of the room they're in and the electronics.

My system has outgrown the Songtowers so I'm looking to upgrade along the Salk line for that reason.  
I would think the more efficient the better.

I wonder why no one mentions Focal.  I tried to like the Aria 948’s and even those were weak on bass.  I did think the tweeters sounded good.
(Pardon me if someone mentioned an idea below first.)

emrofsemanon:  I'd say you are right about pretty much everything you mentioned. I have an extension cord between my fridge and the wall so I can unplug it (a tiny reminder light goes on when I do) for evening low level sessions (even 40 feet away). It is so true how brown noise wrecks low level (or moderate level music, or high level with intricate details). Thank heaven I no longer have force air heat; ugh on that fan.

cakyol, mwinkc: I agree with the ability to use a loudness or other bass control when listening at lower volumes. Bass does disappear. I used to be a purist before I realized it got in the way of enjoying the hobby...  The DSPeaker Anti-Mode 2.0 easily enables a bit of bass or treble boost that is easily defeated as well.

mtbiker:  I'd call avgs in mid-70s 'low volume' (for me). I'm more in the mid-80s I guess (unless real happy about some music I'm playing :-)

+1 on the headphones or just use the loudness control. That’s what it’s for. 
A great low volume speaker is a pair of stand mount Fritz Carerra BE Speakers. I recently picked up a pair and they are fantastic.
i agree 100%, low medium high volumes... fritz’s are superb standmounts

Every single loudspeaker you will ever own will do the same thing. Actually, it is not the loudspeaker. It is your ears. Better yet , it is everyone’s ears. Google Fletchur-Munson curves.
not so simple, nor absolute

while fletcher munson always applies in a technical sense, in the real world, some speakers are at their best when playing at somewhat louder volumes, based on their design... for example, buchardt s400’s have a rear mounted passive radiator that really works well at medium to higher volumes, the bass then becomes full, powerful, room filling, all around terrific... at lower volumes, not so much... contrast, a terrific smaller monitor like a ls3/5a has very limited absolute volume capability, and is best listened nearfield, semi nearfield, and at lower to medium volumes
Matching amp with speaker is, perhaps, the most difficult and central issue in Audio.
It is clear that the 26 watts from the LM is not enough power for the Harbeths. However, I imagine you love that amp.
+1 on Quad 57s. That amp is a beautiful match for Quads!
And the SQ of 57s is still about the best midrange you can get.
And the rebuilt ESS Quads are said to do bass and treble unlike any 57. Harbeths are lovely but cannot compare with the beauty and enjoy ability of 57s. After 64 years, still one of the best.
I have a pair of Tekton 2-10 Perfect Sets which I drive with a pair of Schiit Aegirs - 80 watts each heavily biased to Class A.

They are amazingly good at low volumes.

About $2k/pair for the Tektons.  Great dynamics, detail and when you sit down to listen, it’s very hard to leave - even at low volumes.

If you’re not bothered by big heavy speakers, get the Tekton Moabs-even better.
quad esl57’s, wonderful as they are, have their issues too, which are manifold

there is no perfect speaker, perfect component
My Dynaudio Heritage Specials powered by my Naim Supernait 3 integrated amplifier sound full and extended at 70 to 75db's sitting about 10' away. When I was looking to upgrade my speakers this was one of the most important criteria in my search.
What you need is an amplifier with the good old fashioned loudness control.

Those old fashioned loudness on/off controls where at best only correct at a specific volume. Audyssey has a terrific loudness control that follows the Fletcher Munson curve (Dynamic EQ) and is adjusted according to volume below the reference level. It can be adjusted by setting an offset below the reference level.

I have found Audyssey can at times introduce a ringing around 2k, so I keep its curve filters set to operate below 500Hz. I believe the response filters are independent of Dynamic EQ as I have never had an issue with ringing.

Here's an interesting discussion: