Linkwitz on bass reflex:
In a vented box you add a second resonant structure, which is formed by the compliance of Vb and the air mass in the vent. The driver&Vb resonator and the Vb&vent resonator are coupled acoustically. Energy is transferred between them and used to extend the low frequency response, but at a steeper cut-off rate. The large amount of stored energy for the vented box is indicated by the group delay. It leads to ringing in the time domain and a characteristic bass sound.
Probably 90% of all consumer and professional loudspeakers are vented. Thus this type of bass coloration has become the accepted norm and just because for a given box size the -3 dB corner can be pushed down further (increasing the group delay even more), than when a box is sealed. Bass quantity sells over quality. It's a male thing.