I have a serious Bass addiction...

The range of human hearing is approximately 16Hz to 20kHz. 16Hz is approximately the lowest note a pipe organ will produce. Sub-16 Hz bass is good too, but you feel it rather than hear it. Generally speaking, most floor standing loudspeakers will reproduce from the upper 30 Hz range up to the audible limit. Bookshelf speakers will not plumb as deep, perhap only going as low as 50 Hz, depending on the loudspeaker. If you want explosions to sound like your room is coming apart, if you want to feel the action onscreen, if you want ultra low bass to slam you in the chest, we need a sub that is flat down to around 20Hz.