Yes, it is air movement. But a 12" cone moves more air, does it not, than an 8" cone? The air from a bottom firing sub has to make a 90 degree change in axis before it reaches your ear. Plus, the air most likely disperses in a radius after hitting the floor or floor plate, which means it is hitting rear and side walls directly rather than hitting a far wall and bouncing back as a front-throw speaker would do. A speaker with a throw of 3" must have different air motion than a speaker with 2.5" of throw. I think there are more variables than we might be accounting for offhand here.

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