What makes a speaker sound great at low volume?

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 .

Please..it's BASS, not base...unless we're talking about footers or stands or fans...BASS. Thank you. Also, looking for low tones in audio is called Bass Fishing...they have tournaments...here's a thing, my Schiit Freya has a clicking yet interesting "128-step relay attenuater" that purports to keep levels equal in each channel at any volume and it seems to work. And that Loki...can't say enough about how well it works, although maybe I just did.

Among many many parameters, I'd say the single most important one is the speaker itself. I own several, and I find that usually, bookshelves sound the best at low volumes. If your room is not that big, I would look that way. I have 99dB (Tannoy Westminster GR), 95dB (Tannoy GRF90 GR) and 89dB (XTZ Divine Alpha) speakers. All quite different types, and the Westminster clearly being the best speaker, but the XTZ Alpha sounds far better at lower volumes, and costs 5 times less. It also sounds very very good at high volumes actually, and in my view betters many 20k to 30k speakers out there... I highly recommend that speaker. It also has tuning possibilities to suit taste and/or room.