Demetrios, yes both the T/S parameter Vas and enclosure volume Vb are given simply in cu.ft., not cu.ft. cubed. You've probably seen the formula for calculating the resonant frequency of a driver with a free-air resonance Fs and an "equivalent volume" Vas in a closed box of a certain internal volume. Apparently here a small closed box with a internal volume of 3 cu. ft. is being proposed(about 49Hz).

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Enjoy the music, not the equipment.