Physics of downward firing woofers


Ok ... this question will show my complete lack of knowledge about physics ... but here goes anyway:

Every now and then I come across a speaker with a downward firing woofer. I wonder: why don't the sound waves bounce off the floor back towards the speaker, rattling the bejeezez out of it and / or messing up the woofer itself?

~Jim
128x128jimspov
Kef Reference 3~2.  I have a pair.  Two bass speakers in each cabinet.  One firing down, the other upward.  Both held together with 'force canceling rods.  An OK speaker, they have provided me many years of happy listening.  If the idea was so good I believe Kef would have continued on with the technology.
http://us.kef.com/explore-kef/kef-museum/1990s/reference-series-models-one-two-three-four

Gravity has absolutely no audible effect on a downward firing woofer's performance. None. A speaker cone is extremely light and its performance relative to the pull of gravity is meaningless unless it's a 172 inch cone, and if it wasn't, cones facing forward would also be distorted due to gravity as they'd sag ("cone sag" isn't a thing unless maybe you get a paper cone wet from something like spilled beer or groupie vomit)…or facing up…facing anywhere. Also, I own both front firing and downward firing woofers and they both sound great on the wood floors where they woof...
Downfiring is probably not a very good idea if you have carpeted floor. Unless I am terribly wrong.
I've never seen it make a difference. The Classic Audio Loudspeakers models T-1 and T-3 have down firing woofers. Somehow the bass sorts out how to get to your ears whether there is a carpet or not.

I think there is something to the height of the speaker off the floor, but my Fulton Premieres had down firing woofers and it was a lot closer to the floor than my CARs are. Overall the Fulton was less efficient, but I don't think that had anything to do with the woofers in particular.