It's a great cab, I like BF.
I'm just warning @Al Krow to be careful about how much stock he puts into manufacturers claims. Yes, even BF. A cab with significant output at 30Hz would either be huge, or suffer severely reduced efficiency in the rest of the frequency spectrum, in general, depending on number and type of drivers.
Acme B1/B2/B4 cabs, for example, do have reasonable output at 30Hz, and suffer hugely from reduced efficency as a result. I think they sound great. But you have to carry twice the amount of drivers compared to other manufacturers to get a similar volume because of that huuuge extended low end. And then often you have to HPF that low end out in real world spaces....