I'm not sure about the Black Widows. My gut feeling is that they may be a bit midbass-heavy in this design. Please see my post to Steve on this matter; You might want to check out your options, ideally model its performance before building or maybe try out a borrowed driver that can be swapped if it doesn't work.It is good to have a selection of suitable second-source drivers, so please post back a report of what you find if you try alternate parts.