If you have the manual take a look at page 10 figure 3. That is how you can hook up the two subs, use the y-splitter at the receiver and have the single RCA cable run to each sub.
Here is the page for the sub in case you don't have the manual.
http://www.klipsch.com/na-en/products/ksw-10-overview/
James
Got stopped at the mall the other day
Heard a call from the other way
that I just came from, some ni**a was sayin somethin
talkin bout "Hey man, you remember me from school?" smoke some
Naw not really but he kept smilin like a clown
facial expression lookin silly
And he kept askin me, what kind of car you drive, I know you paid
I know y'all got buku of h**s from all them songs that y'all done made
And I replied that I had been goin through tha same thing that he had
True I got more fans than the average man but not enough loot to last me
to the end of the week, I live by the beat like you live check to check
If you don't move yo' feet then I don't eat, so we like neck to neck
Yes we done come a long way like them Slim a** cigarettes
from Virginia, this ain't gon stop so we just gonna continue