What makes a speaker sound great at low volume?

The problem with Maggies is they have weak bass at low volumes. 

Mid base is great with my 1.7s, even at low volume, but do need to run a sub to get any impact below 50 Hz. Setting the filter on the sub down to 50 or 60 Hz and getting the volume and polarity right, makes a good and seamless interface with the Maggies - at least in my room.....Jim

If you are going to listen at low volumes, you will require a quiet listening space.  Plus, all the comments about Fletcher-Munson and loudness controls are correct.  The ear is progressively less sensitive to certain frequencies as the volume is reduced.  It's somewhat misleading when people say they hear more detail at low volume levels.  They are actually hearing a very upper midrange dominated frequency response which they interpret as more detail.  A well designed loudness control addresses this problem.

What makes a speaker sound great at low volume?

1) Not sure what you mean by sounds great, in what way?
2) The equipment makes the speaker sound great.

Happy Listening.

The one thing that helped my system in low level listening was the use of a autoformer or a transformer volume control . Check out the Dave Slagle Intact Audio site .