For those who are pumping huge amounts of power into their centre and are concerned about dynamic compression below some frequency. Axiom has never defined "huge" nor the frequency. When crossing over at 80Hz, you absolutely don't need an HP driver. But for anyone crossing over at 40Hz, they might want to check with Axiom.

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated