I don't suggest a BSC circuit for a crossover. I suggest an active crossover to handle that. It's just impossible to account for a room without an eq of some kind.
BSC circuits are often put into crossovers. They should be in all crossovers.
Although an active crossover could perform BSC, it's like using an elephant gun when a flyswatter will get the job done
. For the low cost of an extra inductor and resistor added to a cap and resistor for a Zobel circuit (which also should always be used), you get a customized circuit that corrects for the very audible diffraction loss so easily heard with narrow cabinets.
Diffraction loss is no where near as difficult to identify and correct as the bass standing waves and cancellations coming from floor, ceiling, and wall reflections.