great dynamics at a med-low volume?

Most Studio monitors have what you are looking for . Passive or active . Seek them out and give a listen. If you go passive it is harder to find the right amp to go with them . I would personally go with the actives . They are already set up for optimal sound. You will be amazed at the low level detail . Even at the beginning starting price of a few hundred dollars .

one other point on the active monitors is .At any volume they are hard to get to distort. they do not turn to crap when volume is raised .