PCwizard is correct, the Proacs are very listenable at low levels, particularly the older towers that can be filled with sand. You will need a low-impedance amp to drive them or the bass will be out of control.
Speakers for low level listening
I'm currently using Vandersteen 3a Signatures and am starting to think these might not be the best speaker for my needs. I predominantly listen at low to moderate levels. The Vandersteens just seem a little to polite at these levels (coincidentally someone else is selling a pair for this same reason). I'm using them in a relatively small room with not so good acoustics (which could be part of the problem and I'm working on that) and driving them with Audio Research tube electronics. I'm interested in others recommendations for a speaker that excels at low levels. Please keep this limited to $5000 new. Thanks!