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
Chayro gave you very good advice. I listen at low volumes because my ears are sensitive. It's been Magnepan or Quad for nearly 50 years (2905's for a dozen years now, and no thoughts of, or lusts for, change).

Magnepan or Quad. Nothing else comes close.
High efficiency (high nominal impedance and sensitivity). Other parts of the chain can have an influence but efficiency is the primary factor.


What makes a good speaker sound good at low volumes ?
 "" A good Speaker"" and listen to it !
From my understanding Frequency Response changes with Volume.
This is  why you see Loudness contour Switches.
i remember Yamaha amps had adjustable Contour Control.
I remember reading The Fletcher-Munson equal Loudness curves.
https://www.teachmeaudio.com/recording/sound-reproduction/fletcher-munson-curves/