Small-ish Speakers That Come Alive At Low Volume

domestic situation requires a smallish (monitor or bookshelf) speaker with most listening being done at low to moderate levels.

hoping to hear some recommendations for speakers that aren't too large and don't need to be played loud to really come alive.

preamp is Aesthetix Calypso; amp is Spectron Musician 3 mk2

many thanks,
Many Triangle's starting with the tiny Titus XS are exceptional in this area.

Frankly, I would expect most speakers to do very well at all volumes with an amp like that, but the Triangles are exceptional in this area if that is what you are looking for.
I'm listening to my Coincident monitors which are very efficient and resolve at low volumes.
thanks Mapman and Celtic66... i'll check into those. should also mention that the speakers are going to have to be relatively close to the rear wall, so rear ported would not be my first choice.

i know that uses spectron amps to show his speakers, so am also interested in the Strada, as it's the new ref 3.5 minus the large driver. not too much on a'gon about them yet.

i've got a JLAudio sub that i can use to augment bass, so full range isn't an absolute requirement.
With a good sub to blend, the very small, front ported Triangle Titus XS if you find a pair used (<$500) could be just the ticket.

Second the Triangle recommendation.
I have Comete ES's in bedroom system for this exact purpose - clear low-level listening. The front-porting also helps a lot with room placement.
The French have it - in addition to the Titus, I suggest the Focal Chorus 805V or 806V, although I don't recall if their ports fire to the front. I also like the Rega RS1 for this application (which, of course, is not French).
i'll second the rega rs1; a step up from there would be the pardigm sig s1 or s2, which also work very well near the wall.
I had the Cometes and got some 3A De Capos and found they do even better at low volumes than the Cometes especially with dynamics.
Hmm, those De Capos are interesting, 92db efficient and 9 ohm.

Apparently a bit pricier but very interesting at least on paper.
x3 Rega RS1
wow, lots of great suggestions here... thanks, all. i've got some research to do! i should have mentioned - budget is up to $2500 used.
I am a representative of a speaker line called "Role Audio"
One of the best small effective loudspeakers in the World. I highly recommend Role Audio FTL monitors. You will not be dissapointed, excellent in low vol.level listening with detail and the price is great - email for more info.
If you can find the old Red Rose Ribbon Monitor (version where the ribbon tweeter extends upward above the front baffle and cabinet), it's a good choice. Small, with great dynamics and real bass punch, although true bass extension is (understandably) limited and they're not entirely neutral in tonal balance. Overall, very convincing for a shoebox sized speaker.

I also love the Triangle speakers for top to bottom coherence and low level listening. I have the Celius ES in the livingroom and the Comete ES in the bedroom. The Cometes sound great at any sound level but are wonderful speakers to fall asleep listening to at low volumes without worrying about hearing loss. I have not heard the 3A De Capos.
I'm using Gallo Strada's in a nearfield setup with the TR-3 Sub in a small condo. Despite not being particularly efficient, they sound wonderful at low volumes. The presentation is very strong in detail and some might find it bright. They work well without the sub for some acoustic music, but are flat only to about 70 hz in my room.
Given your budget, I might suggest a few other choices:

Aerial Acoustics 5B
Harbeth HL-P3ES2
Joseph Audio RM7XL
Refernce 3A Dulcet
Spender SA1
I would also look at the PSB Platinum M2 which can be purchased new for about $1200 right now.
You should audition the Merlin TSM's. Fabulous sound, all that you are seeking, and compact. I have had many speakers of all shapes and sizes and Merlin's are a keeper for me.
Happy Listening!
Fritz Carbon 7's, simply amazing, only $1750 but better than any monitors I've heard under $4k, and i've heard a lot. I would seriously take a look into it and contact Fritz for advice. No affiliation here, just want to spread the word on a gem of a monitor.
What is the room like? Are there a lot of ambient noises that will interfere with listenig at low levels?

Since a small-ish form factor is important, that rules out electrostats. I would stay away from multi-driver speakers and maybe focus on high efficiency speakers like Spendor. Your amp would be overkill, though.

A little lower on the sensitivity scale, consider a pair of JM Reynaud Twin MK IIIs...if you can find them: A most excellent speaker that does well at lower volumes.
I'll second the Joseph Audio rm7xl