I never used folded horn in a bass rig but I did use them in P.A.
From what I had to deal with they tend to take some rooms really badly, so badly that it is outside of the power of a EQ to tame them. Very powerful and they might sound great in some setting. But drag them elsewhere and you can't reproduce it.
I mean they were OK for starved clubs and bands in the 1980s when lack of power was a serious problem (they had very good efficiency). But now I would rate them more as pets that bite.