Not really, as long as the sub is sitting directly on the floor the enclosure will couple to the floor and the floor will act like a low frequency sound board. If you havn't purchased a sub yet I would get a front firing sub, it might put a little less energy into floor and I like bass transients like drum strokes to be directed at me rather than the floor. I havn't noticed a difference between the two designs on synth or organ music which have sustained continuous tone characteristics.
Scotty
