What makes a speaker sound great at low volume?


Most of the time I hear music at a low volume (wifey, apartment, ....). 

I am looking to upgrade my current speakers, but in my market scanning I would like to understand, if there are certain “metrics” to look for, before I start going to stores for listening. 

Any advice? 
mtraesbo
I am thinking of getting the Luxman 509x for my office and one of the big reasons for it is the Loudness switch. It would help big time when I am working in my office at 3AM.
I use the tone controls on my McIntosh C2500 preamp at low volumes.  Does wonders.
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"What makes a speaker sound great at low volume?"

The "Loudness" switch on my McIntosh C22 preamp...
@mrdecibel I agree . Hi end vintage gears was equipped tone control
loudness control etc, so this is problem with all hi end which you
see on the market now. Is very rare to see all new amp, with any
tone adjustment,  so this issue is depend from speakers . Sensitivity is
absolutely no important. take a look on the freq . responce---
if it is go  slightly up in midbass or bass   it will be play good on the
low volume,
Properly designed loudness controls, Schitt Loki, or another eq ( in the tape monitor loop ), would answer your concern. Headphones are another route to take. I am not a scientist, but been in this hobby for so long, these are my experiences. Speakers load a room differently at various volume levels, no matter what equipment you have, and our ears are quite unique instruments. Happy Fathers Day to all the pops out there ! Enjoy ! MrD.
My former Krell 600 - Dynaudio Consequence combo was hopeless on low volume. It would have been better to listen to a small bookshelf system. It was only on higher volume that the wolf came out of the lair, so to speak. Music started sounding great, and even glorious, but only at very high volume. My present Atmasphere MA-1 - Audiokinesis Dream Maker combination offers better sound at lower volume. Even though I could have asked for even more, in this respect. Here also - even if these amps run fairly "flat" in class A - I find that to get the sound right, I need to turn up the volume. I think that getting more sensitive speakers is the way to go, but it is not the only answer.
You should go listen to any LS3/5A type of speaker. Spendor, Harbeth, Stirling , etc., etc. make this design!
I love the sound of my Ref 3A de Capos at low volume detailed

using with a 4wpc decware amp
Buy a pair of Quad 57's! Either in good working condition or refurbished. They will provide all the air and detail at low volume that you could desire! You will be very happy! I own two pairs! And a good amp match for them would be a Quad 303 (I have one, along with a 405 and a rare pair of the 50 Mono's).
kalali is correct, omega speakers have 98db sensitivity, like my rs8 supercone, high output alnico 96db ? Then get a nice tube  power amp.
Crossovers are the most ignored, but most important consideration, IMHO. I recently went through the same process you’re going through now. I ended up with the 2 way Joseph Audio Pulsars, which provide everything I need ... great crossover (a Modafferi based and JA modified infinite slope), fabulous sound at low and high volumes, low distortion, and great looks. Couple them with a good sub and you’re good to go. BTW, I went from full range B&Ws to the 2 way Pulsars, and can say that I much prefer the more coherent sound of the 2 way with a sub than the full range speakers. 2 way speakers can "disappear" in a way that full range can’t. Of course, your room size will have a major impact on which way to go as far as speaker size is concerned.
In terms of what metrics to look for, in my experience the speakers with very high sensitivity, >96dB, combined with high load impedance, >10ohms, tend to sound more detailed and full at lower listening volumes. I have a pair of single-driver full range horn loaded speakers in my upstairs converted listening room paired with a 10wpc integrated amplifier and its perfect for (almost) near field low volume late night listening.
One thing I'd say you likely Don't need (necessarily) are expensive, overdesigned drivers. Even ordinary paper cones are quite competent and capable of very nice combinations of musicality and detail/resolution. An exception in your case might be planar/electrostatic/ribbon designs. These, if they fit your budget, can offer even more separation/clarity/transparency and so forth.

Where I think the most design money must be spent in your case might be on the crossovers and it will be a challenge for you perhaps to find an example with nice, ordinary drivers combined with excellent (expensive) crossovers at an affordable, or entry-level price. Of all the design components in a speaker, I'd say generally that the crossover is the single biggest obstacle to good sound. But this is only because most manufacturers end up giving it short shrift - they likely could do better, but they simply don't. Most people don't realize just how important crossovers are to the kind of sound they are looking for and most makers seem content to let that sleeping dog lie, if you will, rather than try to educate the buyer. But for you, crossoverless designs are at least something to consider and to go and hear, if you have the opportunity. Single-driver designs stand to save you some big bucks and a long time looking by doing away with the crossovers altogether. The only real catch to look for might be the relatively rolled-off highs since no single driver is truly considered full-range.Crossovers may take the single biggest hit to sound quality in the overall resolution/clarity/transparency/coherency package - perhaps especially the coherency - whether it be dynamic, tonal, vocal intelligibility or spatial coherency.

All that I'd add is that while you'd want speaker sensitivity to be modestly high, you certainly don't want it too, too high, or you might be dealing with a system hum that is most annoying at low volume levels and that you then can't get rid of without swapping out gear. In the low 90's might be ok, but 100+, almost certainly not.
Yes - look for a speaker that sounds good at low volumes. I’m not being sarcastic. One of the many mistakes I found that people make is doing demos at loud volumes and then deadening their ears. I think ears react to sound like pupils to light. If you go into a dark room - the eyes open up and then you can see. If you start listening at a volume that’s a bit too soft, your ears open up and the volume gets more normal. Then if you kick up the volume just a smidge, it sounds dynamic and full. If you listen at low volumes you also might consider an amplifier with tone controls to allow you to add a bit of bottom and top to the mix when you’re listening softly. I’ve worked pretty hard at putting together a low-volume system and there’s no real secret, IMO. Demo the speaker in your home and see if it sounds good at low volumes. That’s pretty much it.
In fact - try the low-volume experiment with your current system.  Start a little too soft, listen for a few minutes until it feels comfortable and then turn it up just 1 notch.  Maybe you're ok as is and it's just your listening technique.  That saves a few bucks.  Good luck.