Ground level woofer?

A dumb idea,no?. Why used? i.e YG
Research Roy Allison loudspeaker designs.
Thanks! That lead to some fascinating reading. Did not get to technical details of having the bass at the bottom but fascinating history of speaker design and the persons involved. Opened my eyes and revealed much that gives a much better understanding of where today's efforts come from.
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Thanks Bob. There must be powerful reinforcement from proximity to the floor; perhaps improving sensitivity?