Originally Posted by TJElite

For rap, a properly designed single reflex is hard to beat. With the right design and driver, you can also sometimes get a wide enough band to play other stuff, as well. For real accurate sound, though, they still usually have too much group delay (bass doesn't 'line up' with the rest of the music).

I'd still go with an active xover, though...the bandpass design does acoutically taper on both ends, but the amp is still wasting energy sending frequencies to the sub that you aren't using, and the sub is wasting energy trying to reproduce them.