Open Baffle loudspeakers.

+1 @grannyring on Nola.  In my experience, open-baffle cone drivers are a great compromise between completely closed-box speakers and planar or electrostatic designs.  Done well, I find open-baffle dynamic cone speakers in general to be more open sounding than box speakers but with greater tonal density and "oompf" than flat panel designs along with fewer bass production and integration issues.  Nola in particular has got me rethinking what my own end-game speakers may end up being precisely because of this issue.  Hearing their Grand Reference towers at a show in NYC years ago continues to be the single most impressive audio reproduction experience I've had. 

Spatial is another brand not mentioned previously that embraces an open-baffle architecture. 

I have a pair of Spatial Audio X1 Turbos.  They're wonderful, with tight, solid bass and a good presentation all the way up through the high end.

Then, last Christmas, I decided that I deserved a pair of Spatial X2s.  Even more wonderful, with fabulous bass down to 18Hz, and an air motion transformer handling the high end.  They image like crazy, and are utterly non fatiguing.  I listen to them for hours at a time.

I put the old Spatials in my system in my finished basement apartment.  They, and I, like their new home.