Insights
The octave that is missing.
The deepest bass is a job of its own. Why it pays to entrust it to a dedicated piece.
The hardest octave
The lowest notes call for a great deal of air and energy: they are the most demanding part to reproduce. Asking them of a slender loudspeaker too means setting it after something that is not its own.
Freeing the others
A dedicated subwoofer takes the deep bass upon itself and leaves the other loudspeakers only what they do best. It is not a third speaker: it is what frees the first two.
Where it is not seen
Deep bass is almost impossible to locate: the subwoofer can stand out of the way. In stone, it remains an object all the same — never a black box to hide.