I've never owned a pair, but I auditioned the DBLs with active filters ten years ago, and I still remember them because I had one of the best audiophile Sundays of my life! We were a group of audiophile freaks invited by a rich audiophile buddy to eat, drink a listen to music all day long! The guy lived close to Marble Arch (London, UK)... what a Sunday for an (Italian) student like me! Ok, let me finish with pure nostalgia, and let me talk about the sound of the DBL.
They produce a massive sound stage, with accurate tone, and good (but not excellent) dynamic (see below). Despite their large size, they can adapt to most rooms due to the large baffle. However, if you want highly detailed 3D imaging, you need to listen to them at a distance (not less than 4mt) which means you need a lot of power to reach truly studio-type SPL peaks.
I am not sure it makes sense to buy a pair of DBL in 2022. Their strong limit is the "true" dynamic that any statement top speaker should be able to do. The dynamic limit is not because they are bad speakers but because their drivers are now old. As for most speakers of that age, they do not come to life if not pushed hard, but if you push them hard, distortion becomes an issue. You would expect to be able to run those beasts very hot at concert levels. If you do it, you will be disappointed by the compression. I know that nobody really listen to music at concert levels at home, but I believe that a statement speaker should be able to do it. I won't pay 100K for a beautiful car that is not able to do 250Kmh although I rarely do 120Kmh. Of course, I am not talking about reproducing simple soft music like those crappy audiophile recordings played at hifi shows, I am talking about playing demanding music from large orchestras, rock, electronic, etc.
From time to time, I have the idea to clone the DBL philosophy and build a modern version. But I don't have the tech skills. That's why I spotted this post, because I google for some DBL-clone projects from time to time.
Regards
Pierre
PS: by the way, if some DBL owner read this post, can you tell me what is the vertical distance of Tweeter, Mid, and Woofer? I mean the vertical distance between the floor and the center of the driver.