It's been 23 years since I owned a reference level box speaker. Back then it was a pair of Revels that I had built a room around. They were very good sounding speakers but not all that revealing.
It was only after dismantling that room and changing over to panel speakers that the missing resolution returned. With Magneplanars installed, once again I was better able to hear the sonic differences in cables and equipment. I haven't been back to boxes since.
Yet it was never boxes that stopped the resolution. Panels just offered the best support for building a dipole—and dipoles have sonic characteristics that appeal to me—which is no doubt why, even with box speakers, I have always liked Arnie Nudell's penchant for rear-mounted out of phase tweeters (creating a dipole where it counts).
So, I don't want it to be said I prefer one type of speaker over another.
Speakers—both panels and boxes—are the most problematic of all components in the system. Their distortions, frequency shortcomings, phase irregularities, and sonic personalities only make worse the tough choices we all face trying to decide between panels, boxes, baffles, driver types, heights, aesthetics and practicality.
As PS Audio's new FR series of loudspeakers gets closer to becoming a reality my decades of devotion to panel speakers draws near to a happy ending. Boxes are eminently better suited to the task of enclosing drivers than are panels and I for one am happy to be getting closer to having the best of both panels and boxes.
These are exciting times for me.