2x mono to 2x RCA is perfect.
 
For short distance (10 meters or less) some believe unbalanced is superior to balanced, even when you have the choice between both. Not sure why but from what I understood it takes the balancing process out of the way, so less parts in the circuits, so "cleaner". Google this if you have to. Hell even google "mastering audio unbalanced".
 
Pretty sure Gary is having a nice experience even if he is unbalanced.
 
The sub connectors accept unbalanced connections so no problems about conversion or whatever here. 
 
For short signal path, balanced is not automatically the best choice. Ground loops are easier to cure but a well built unbalanced system will perform as well as a balanced one.