if you can still return the svs i would and try to get something smaller.
The HSU 1220 is 12 inches(but really tall) and can be turned on it side. this way you can put it under a couch or something.\

i wouldnt go for the attic option. Part of the expierence of the subwoofer is being able to feel it. and if the subwoofer isnt on(or in) the ground you are losing out.

Once You Pop You Can't Stop